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4 Transuranic Waste Characterization Program This chapter describes the current (2003) contact-handled transuranic (CH-TRU) waste characterization program as approved by the New Mexico Environment Department (NMED) and the U.S. Environmental Protection Agency (EPA), and implemented at the five U.S. Department of Energy (DOE) waste generator sites shipping waste to the Waste Isolation Pilot Plant (WIPP). Emphasis is given to the concept of "Acceptable Knowledge" (AK), a central feature of the characterization program. Lessons from experience and future opportunities to take advantage of, in the context of waste characterization, are presented at the end of this chapter (Section 4.6~. 4.1 Overview of the Current Waste Characterization Program The committee describes the CH-TRU waste characterization program as a suite of characterization activities that are performed at generator sites before shipping waste to WIPP (see Figure 4.~. These activities address requirements set forth by Congress (through the Land Withdrawal Act), EPA, NMED, and the U.S. Nuclear Regulatory Commission (USNRC). Regardless of the time of generation (i.e., existing or to-be- generated), TRU waste is divided into three categories for characterization purposes: homogeneous waste, debris waste, and debris waste that needs repackaging. All waste being characterized is solid waste because liquids are prohibited in WIPP. Homogeneous solids are solid residues such as inorganic sludge, salt wastes, or pyrochemical salt wastes that are expected to contain TRU radionuclides, toxic metals, and solvents. Homogeneous solids range from de-watered sludge with the consistency of paste to solid cement. Debris waste, as its name suggests, consists of heterogeneous solids. Debris waste includes such items as protective clothing, gloves, rags, laboratory instruments, and parts of equipment such as gloveboxes. Some debris waste inventory has to be repackaged in a form suitable for shipment (see below). Characterization activities vary depending on the category of solid waste. Wastes are characterized following the same set of activities independent of their time of generation (i.e., existing waste and to-be- generated waste are characterized in the same fashion if they belong to the same waste category). According to DOE, there are approximately 750,000 drums of CH-TRU waste remaining to be characterized (DOE-CABE, 2003~. Waste characterization activities for CH-TRU waste, including recent changes, are described in the following sections based on information provided by DOE (DOE- CBFO, 2002), the Center for Acquisition and Business Excellence (DOE-CABE, 2003), and the New Mexico Environmental Evaluation Group (EEG, 2003b). A detailed description of the characterization activities is presented in the Waste Acceptance Criteria (DOE-WAC, 2003) and in Attachment B of the HWFP (HWFP, 2003~. 4.~1 Acceptable Knowledge AK is a term that encompasses historical process knowledge and information from previous testing, sampling, and analyses of waste. DOE coined this term based on - ~ ~ , . . . . · . . .. . . . 39
40 i Improving the Characterization Program for Contact-Handled Transuranic Waste - Debris Waste At= Homogeneous Waste - Debris Waste (to be Repackaged) AK 1 | RTR l | Segre ration/ | L Rework NDA [: ~ | Gas Generation | L Testing | | Statistical VE | , Data Management Audit 1 - ...... Shipment , AK 1 RTR NDA 1 DAC/HSG 1 ; Gas Generation Testing L StatisticalCoring I , 1 | Analyses , Statistical VE | Do Ita l Management | Audit l ~ v Shipment - 1 , ~ , AK | Segregation/ | I Rework l ~3 NDA 1 | DAC;HSG l ~ , Gas Generation Testing Data Management Audit l __ Shipment FIGURE 4.1 Summary of typical characterization activities in the current contact- handled transuranic waste characterization program. Characterization activities may vary among generator sites. NOTE: AK = Acceptable Knowledge; DAC = drum age criterion; HSG = headspace gas sampling and analysis; NDA = Non-destructive assay; RTR = real-time radiography; and VE = visual examination. =
Transuranic Waste Characterization Program 41 EPA's similar concept of process knowledge; EPA has recently adopted the term "Acceptable Knowledge" when referring to WIPP processes to be consistent with DOE terminology (see further discussion in Section 4.4~. 4.~2 Real-time racliography and visual examination Real-time radiography is a non-destructive examination technique usually involving X-ray imaging technology. Visual examination is an invasive process that involves opening a TRU waste container to inspect its contents. Radiography, visual examination, or a combination of both are used on every waste container to verify its physical form, confirm the absence or presence of prohibited items, and evaluate the masses of various fractions of materials important to the performance of WIPP, such as ferrous metals, non-ferrous metals, cellulose, or plastics and rubber. With recent changes to the HWFP, generator sites have the choice to characterize to-be-generated waste with visual examination or radiography, the latter to be verified through visual examination on a statistical fraction of containers as a quality control check. Sites may elect to use visual examination before or radiography after packaging, either separately or together, as long as 100 percent of the containers undergo confirmation of AK. The visual examination process can be performed in two ways: 1) two certified operators perform the visual examination process; or 2) a certified operator examines a videotape of the waste removal and sorting process. In addition, approximately 1.2 percent of the containers ultimately disposed of at WIPP (or approximately 9,000 drums) must undergo a quality control check of radiography results by visual examination. Containers found to have prohibited items are also visually examined and reworked (i.e., the container is opened in a gIovebox and prohibited items are removed, see below). 4.~.3 Non-clestructive assay Non-destructive assay is a general term for a number of non-invasive techniques, such as gamma spectroscopy and passive-active neutron measurement. These techniques provide information about the radionuclide content of waste and whether waste is TRU without destroying the waste or waste form. 4~.4 Drum age criterion and heacispace gas sampling and analysis Both the NMED and the USNRC have requirements for headspace gas (HSG), which is the gas clevelopecl in the void volume of waste containers (e.g., 55-gallon drums). The NMED requirements are to support hazardous waste determination. The USNRC requirements are to determine that only non-flammable gases are present. Both requirements are satisfied by a single procedure, called headspace gas sampling and analysis. Headspace gas sampling and analysis is used to: identify and quantify volatile organic compounds (VOCs4), confirm AK for hazardous waste identification, and identify and quantify flammable gases (hydrogen and methane) for transportation purposes. There are 29 VOC species that are required to be characterized quantitatively in the WIPP HWFP permit. The amounts of VOCs in the waste shipped to WIPP to date have been small (about 5 ounces summed over the 40,000 drums emplaced in Panel 1~. The predominant species found (more than 90 percent by mass) are acetone, 1,1,1-trichloroethane, toluene, methylene chloride, and carbon tetrachloride.
1 42 Improving the Characterization Program for Contact-Handled Transuranic Waste Heacispace gas sampling and analysis uses gas chromatography/mass spectrometry, flame-ionization gas chromatography, or Fourier-transformation infrared spectroscopy to analyze headspace gases. This characterization activity also involves aging the drum for a prescribed number of days (up to 242) to allow equilibration of gases in the headspace prior to sampling and analysis. The required waiting time prior to headspace gas sampling is referred to as the drum age criterion. All waste is verified by ~ 00 percent headspace gas sampling, except homogeneous solids without VOC-related hazardous waste codes, or thermally treated wastes (see Section 4.2~. A small portion of the containers (approximately 1.8 percent) requires new vents prior to shipping,2 and over two-thirds of the containers (68.7 percent) require documentation to show compliance with the drum age criterion. 4.~.5 Gas generation testing Gas generation testing at elevated temperatures is performed for transportation requirement purposes although it is not part of the WIPP Waste Acceptance Criteria or the waste analysis plan in the Hazardous Waste Facility Permit (HWFP). This test is used to measure gas generation rates for wastes whose historical information suggests that flammable gases might exceed the limits for transportation. In the test, waste drums suspected to contain higher-than-normal concentrations of hydrogen-bearing or organic compounds are heated to an elevated temperature to measure the amount of gas generated. This method accounts for both radiolytic hydrogen or methane generation (the predominant source of flammable gases) and any VOCs (if present) that might be driven out of the waste into the headspace gas by elevated temperatures during shipping in the summer months. If the test shows that the container would not generate enough flammable gas during shipping to produce an explosive mixture in the transportation package, the container may be shipped. Approximately 9 percent of the remaining legacy waste population of containers, i.e., 41,000 drums (S,550 cubic meters), is expected to require elevated-temperature gas generation testing (DOE-CABE, 2003~. 4~.6 Homogeneous waste coring and analysis Homogeneous waste forms can be sampled in a way that is representative of the bulk of the waste. These wastes undergo statistical coring and analysis, which determine the chemical composition and concentrations of hazardous waste constituents and the toxicity characteristics of waste in containers (see Section 4.2~. "Coring" is a process wherein a container of solids is opened, and a hollow drill bit is used to obtain a core that reaches from the top of the waste to a depth near the bottom of the container. The core is taken from the bit and "sampled" by removing either one or three thin sections from along its length. These sections become the sample. For retrievably stored wastes, the HWFP states that homogeneous sampling and analysis is used to determine the toxicity "characteristic" in the waste; that is, the hazardous compounds that are considered toxic only if present above the threshold concentrations listed in 40 CFR 261.24, or if the "listed" wastes under Subpart D of 40 CFR 261 are present. The HWFP requires analysis of homogeneous samples for total 2Most but not all retrievable stored drums have filter vents installed at the time of generation. When a drum is exhumed or retrieved and does not have a vent, usually the site safety procedures require immediate venting (installation of a filter). AISO, there are some waste streams that have shown filter degradation over times, and those streams have a routine filter replacement schedule. Finally, at certain sites, the headspace gas sample is collected through the filter; in this case too, the filter must be replaced.
Transuranic Waste Characterization Program 43 VOCs, semivolatile organic compounds (SVOCs), and analysis for metals. Tables in the HWFP list over 30 chemicals for the VOC analysis, ~ ~ for the SVOC analysis, and 14 metals that are the primary targets, but other hazardous constituents may be added to the list for a waste stream if they are found in more than 25 percent of the samples from that waste stream (EEG, 2003b). 4.~.7 Segregation or rework Segregation or rework are the activities required when a container is found to be out of compliance with the Waste Acceptance Criteria (e.g., if real-time radiography or visual examination finds a prohibited item in a container, that container is segregated from the others, the prohibited item is removed, and the waste is repackaged). 4.~.8 Repackaging Repackaging involves removing all contents from the original waste container, sorting, size-reducing, compacting,3 and putting them into new containers. During repackaging, waste that is not suitable for shipment and does not meet the hydrogen generation limits for transportation is removed from the containers. 4.~.9 Data management Data management includes the data-gathering operations and quality assurance activities that the waste generator and the Department of Energy (DOE) perform to assemble, record, and certify the information on each container and to assist in managing each transportation payload container. DOE uses a quality assurance process based on that used by nuclear power plants (NQA-~ ) on all TRU waste characterization and certification activities. The quality assurance process that is now described in the HWFP requires, among other activities, the review, validation, and verification of all analytical data; reconciliation of analytical results with data quality objectives (DQOs); satisfying data reporting requirements; and identification, documentation, and reporting of all non-conformances. Data review determines whether raw data have been collected properly and ensures that raw data are properly "reduced" to an acceptable format. Data validation confirms that the data reported satisfy the requirements of the waste analysis plan and are accompanied by the approval of an authorizing official. Data verification authenticates that data as presented represent the sampling and analysis activities as performed and have been subjected to the appropriate levels of data review. Other quality assurance activities, such as statistical calculations for random sampling, confidence levels from analyses, evidence of independent technical review, supervisor review, quality assurance review, chain-of-custody and sample preservation are also described in Attachment B5 of the HWFP (HWFP, 2003~. As part of data management activities, sites transmit required characterization, certification, and shipping data to WIPP prior to shipping using the WIPP Waste Information System. This system consists of an electronic database equipped with edit- limit checks to ensure that the clata representing the waste payload containers comply with the Waste Acceptance Criteria. Only DOE, EPA, NMED, the New Mexico Environmental Evaluation Group, and corridor state authorities have access to information in the database. 3Size reducing and compacting are performed only at certain sites, such as the future Advanced Mixed Waste Treatment Facility at the Idaho National Engineering and Environmental Laboratory.
44 Improving the Characterization Program for Contact-Handled Transuranic Waste The HWFP data management process is comprised of seven layers of review; some of the reviews are performed at generator sites and some at the DOE-CarIsbad Field Office. There are also quality assurance activities for transportation purposes, as described in Appendix D. According to DOE, it takes about two months for a waste container to go through the entire data management process (Powell, 2003~.4 4.~10 Audits Audits are the operations conducted by DOE's auditing branch at generator sites to ensure that waste characterization sites conduct waste characterization activities in accordance with the HWFP Waste Analysis Plan, and that the information supplied by each site is managed properly. EPA, NMED, and the New Mexico Environmental Evaluation Group participate in these audits as observers and confirm that characterization requirements are addressed. They may request corrective actions to a site's characterization process if they believe it does not comply with the regulations. 4.2 Statistical Sampling or 100 Percent Confirmation? , _ Some characterization activities are performed on all containers (e.g., non- destructive assays, headspace gas analyses, development of AK, and data management), whereas others apply to only a selected portion of the inventory (see Table 4.1 in Section 4.6~. For example, homogeneous solids, soils, or grave! without VOC-related hazardous waste codes, or thermally treated waste may qualify for reduced headspace gas sampling. Debris waste does not undergo homogeneous sampling and analysis, and only a statistical fraction of homogeneous solids, soils, or grave! undergoes homogeneous sampling and analysis. An example of statistical sampling is illustrated in the case of homogeneous waste solids. In this case, there are hNo levels of statistical significance. The first is the statistical significance of the samples collected from a container. The second is the statistical significance of samples collected across a waste stream. The first part of statistical significance refers to sampling a container in a statistically representative way (more accurately called aliquoting); this can be done in several ways. One of these ways is coring and aliquoting from different layers (at least three are required in the HWFP). If the waste is in a cement matrix, coring involves drilling into the solid waste to collect aliquots. If the waste form allows it, sample gridding (i.e., pouring the powder into gricis and then randomly aliquoting from the celIs) can also be used to minimize entrainment of particulates. The second part of statistical significance refers to how accurately a subset of samples from a waste stream represents the true mean of a parameter (e.g., the average lead metal concentration). In this case, the population variance must be known before deciding how many samples to collect. The greater the variance, the more samples are needed to achieve a given accuracy (as specified in the HWFP). For instance, the HWFP specifies how many waste containers from a determined waste stream must be sampled. From the results of the analysis of this first set of containers, the variance of the population is estimated, and a new calculation of the number of samples from that waste stream is made to achieve the required confidence level on the mean. If necessary, more containers are sampled until the required accuracy is achieved. Of course, if the first subset sampling results in the required accuracy, there is no need to continue sample collection. According to DOE-CABE, approximately 0.5 4DoE submitted a data management permit modification request to NMED on June 28, 2002 to implement automating data processes that would eliminate four of the seven levels of review. NMED has not issued a decision to date.
,: : ~ Transuranic Waste Characterization Program 45 percent of the remaining containers, or 375 drums, will undergo statistical coring and analysis for hazardous constituents (see Table 4.1 in Section 4.6~. 4.3 Site-Specific Characterization Activities Characterization activities may vary somewhat from one generator site to another, depending on the type of waste to be characterized and on terms negotiated between the state in which the waste is generated and DOE. For example, the characterization activities at the future Advanced Mixed Waste Treatment Facility in Idaho and at the Savannah River Site are somewhat different. The Advanced Mixed Waste Treatment Facility has the capability to "supercompact" waste for volume reduction and more efficient operations.5 Therefore, real-time radiography and/or visual examination are performed prior to compaction ancl/or final waste packaging. This facility also has the capability to size-reduce and repackage wastes from oversized waste boxes. EPA and NMED must approve the suite of characterization activities at each site before allowing waste to be shipped to WIPP. To date (December 2003), the Advanced Mixed Waste Treatment facility has not been certified. The Savannah River Site has adopted a "fast-scan" approach to real-time racliography, which consists of performing a quick radiography scan of the waste containers during the weekend to identify prohibited items. Containers with prohibited items are set aside to be segregated or reworked at a later date, while those that do not appear to contain prohibited items follow the "quality-assured" characterization activities during the week. This approach is not part of the Waste Acceptance Criteria or the HWFP and was introduced by DOE to increase the efficiency of characterization activities (see also Section E.3~. A further example of site-specific changes to the characterization program is the headspace gas sampling and analysis process. At the Savannah River Site, the container is placed into a sampling chamber after it has met the required drum age criterion. A remotely controlled drill places a sampling port in the lid. First, a sample of headspace gas is drawn into a flame ionization detector, which quickly provides hydrogen and methane concentrations to determine if the headspace gas is below flammability limits for transportation purposes. Then, a second sample is drawn and injected into a gas chromatograph-mass spectrometer to analyze for 29 VOC species specified in the HWFP. During the 3100 Project at the Idaho National Engineering and Environmental Laboratory, each container was sampled using a filter vent with a septum entry. A needle was inserted into each drum (manually) and a headspace gas sample was drawn into a canister to be combined with other canisters. These were shipped in drums (1 0 at a time-one canister per drum) to an analytical laboratory at some distance from the drum sampling area. First, ten aliquots (one from each canister) were taken. The aliquots were combined and a sample was injected into a flame ionization detector for flammability (hydrogen and methane). A second sample of the combined aliquots was injected into a gas chromatograph-mass spectrometer for VOC analysis. The difference between the Savannah River Site and the Idaho National Engineering and Environmental Laboratory 3100 Project analytical methods is primarily in the lower limit of detection. With the Idaho National Engineering and Environmental Laboratory aliquots combined, the minimum detection limits are significantly increased. 5A recent report by DOE's Inspector General noted that there would be a 6 percent volume reduction for the 65,000 cubic meters of TRU waste from Idaho instead of the 35 percent initially estimated (DOE-IO, 2003~.
46 Improving the Characterization Program for Contact-Handled Transuranic Waste However, only one gas chromatograph-mass spectrometer analysis per batch is needed, so some time is saved. The Rocky Flats Environmental Technology Site obtained an exemption from the NMED requirement to perform headspace gas sampling and analyses on thermally treated waste (see also Sections 3.3.2.1 and E.4~. DOE also submitted a request for HWFP modification to obtain an exemption from headspace gas sampling and analysis for the seated sources stored at Los Alamos National Laboratory (see Section 2.3~. NMED denied this permit modification request because DOE did not provide sufficient evidence that sealed sources do not contain hazardous waste (NMED, 2003b). The use of AK alone to determine the flammability of headspace gas is allowed by the USNRC, but DOE elected to measure flammable gas concentrations in each container. According to DOE, the quality assurance requirements for the headspace gas analysis are more demanding than those for the flammability test for transportation purposes. First, headspace gas sampling and analysis requirements in the HWFP are linked with the SW-846 (EPA's Methods Manual), which introduces precision, accuracy, representativeness, completeness, and comparability criteria. Second, all of the headspace gas sampling and analysis requirements are subjected to scrutiny during the audit process. Third, other quality protocols come into play such as: 1) calibration standards at the ppm level, 2) instrument controls, and 3) follow-up analyses for "Tentatively Identified Compounds" at concentrations above the "Program Required Quantitation Level" for all 29 VOC species in the WIPP Part A Permit list. While the actual analyses and setup for flammable gases and VOCs require similar technical efforts and costs, meeting the HWFP requirements to determine the VOC concentrations requires a greater data management effort because of the number of analyses, associated calibrations, and quality assurance requirements (Nelson, 2003~. ~ , _ _ , _ _ , 4.4 Acceptable Knowlec~ge The first step in the characterization process is the compilation of all relevant information available on the waste into an auditable record. This information is called AK. The AK record must include information that describes the amount and how the waste was generated and managed, as well as the physical, chemical, and radiological properties. AK also includes information regarding the raw materials used in a process or operation, process description, products, and associated wastes. AK documentation includes the site history and mission, site-specific processes or operations, administrative building controls, and all previous and current activities that generate a specific waste (DOE-SAR, 2003~.6 According to the EPA's definition, AK may consist of a variety of information, such as the following (EPA, ~994~: detailed waste analyses at the time of generation, if performed in accordance with an acceptable quality assurance program; studies of the waste generating processin addition to information about the process flowsheet and its goals, these may include data from the generator's process, or from similar generation processes undertaken elsewhere, and from experiments involving surrogate waste processes or products; waste characterization data obtained from facilities that send wastes off-site for treatment, storage, or disposal; 6EPA is currently in the final stages of a rulemaking to change 40 CFR 194.8 to streamle its certification process of confirmation at generator sites. EPA has indicated that it will provide a more focused definition of AK in that rulemaking.
Transuranic Waste Characterization Program i 47 the generator's records of analyses performed before the effective date of the Resource Conservation and Recovery Act (RCRA) regulations; or other historical data relevant to characterization of the waste (e.g., procurement records). Acceptable Knowledge is developed on a waste stream basis. Once a generator site determines that a particular waste stream is suitable for disposal in WIPP, the generator begins collecting all relevant information available (i.e., the AK) for the waste stream. The collected AK is then reviewed and released by the generator site, following the regulators' procedures. This preliminary AK report contains the generator's assignment of a waste matrix code and a summary category group.7 The lager specifies the physical form of the waste (homogeneous, soils or gravel, or debris) and hence the sampling and characterization regimen for the waste streams. The generator then submits to WIPP a Waste Stream Profile Form (brief summary of the AK report, with citations) and the AK Summary Report, which is approved by WIPP prior to shipment of any containers of waste from the waste stream in question. The EPA recognized that under certain circumstances, the use of existing knowledge of a waste stream might be preferable to performing a detailed characterization. As acknowledged in joint USNRC/EPA guidance, mixed wastes constitute one of those circumstances because of the potential for personnel exposure inherent in radioactive waste characterization (USNRC/EPA, 1997~. Although written for commercial mixed waste generators, the guidance states that it could apply to transuranic waste. Therefore, this guidance may also be useful for federal facilities that generate mixed waste, such as WIPP waste generator sites. The concept and use of AK is central to the characterization program for TRU waste because it determines the sampling and characterization regimen for the waste. _ A e ~ ~ en ~ ·e The AK process delineates the waste stream. If the required elements cannot be documented in the AK summary, the waste must be treated as "newly generated waste," according to DOE's terminology. AK forms the basis against which the results of other characterization methods are compared. This process is termed "confirmation of AK." The characterization methods used to confirm AK include non-destructive assay, headspace gas sampling and analysis, radiography and visual examination, and homogeneous solids sampling and analysis (DOE-CABE, 2003~. 4.4.1 Uses of Acceptable Knowlec4e The EPA allowed the use of AK to determine whether a waste stream was "characteristically" hazardous, to comply with the RCRA requirement to analyze a representative sample of the waste and determine its disposability. AK is used to address several characterization requirements set forth by different regulatory agencies. Uses of AK in the characterization program are the following: determine that waste is defense-related and TRU; assign waste to one of the ~ ~ waste matrix code groups (see Chapter 3~; assess the presence of toxic material; assess the presence of listed RCRA waste; determine the absence of non-radionuclide pyrophoric materials; determine the absence of liquids; determine the absence of incompatible wastes; 7For a definition of waste matrix code and summary category group, see the Glossary.
48 Improving the Characterization Program for Contact-Handled Transuranic Waste determine the absence of containerized gas or explosives; determine the absence of reactive, corrosive, or ignitable waste characteristics; track the presence of polychIorinated biphenyIs;8 determine the absence of sealed containers greater than 4 liters; and · determine the fissile material content. If the waste was generated after the implementation of RCRA (1 976), many of the above physical and chemical characteristics of waste are gathered from the hazardous waste codes assigned to the waste at the time of generation. 4~4.2 Qualification of Acceptable Knowledge Based on EPA's requirements set forth in 40 CFR ~ 94.22(b), historical information cofIected before an approved quality assurance program is in place must be qualified before it is used as AK. Title 40 CFR 194.22(b) lists four methods that may be used individually or in combination to qualify such data: 1. Peer review. In general, the use of peer review requires a structured and documented review process. 2. Use of corroborating evidence. This may include other data generated prior to approval of the quality assurance program or data on other waste streams that should be able to represent the one being considered. 3. Confirmation by measurements. These confirmatory tests must be performed in accordance with an approved quality-assurance program. 4. Qualification of quality assurance program. In practice, this means demonstrating that the quality assurance program in effect when the AK was generated was equivalent to a quality assurance program approved by WIPP.9 Currently, confirmation by measurements is the only method used to qualify existing information, as negotiated between DOE and its regulators. All information about existing waste collected before the establishment of a quality assurance program must currently be confirmed by some type of measurement to become AK. The types and frequency of confirmatory measurements vary depending on the particular waste and the site. For example, for debris waste, information is confirmed by using either real- time radiography or visual examination. 4.4.3 Accuracy of historical information A key question is how to verify the accuracy of historical information about waste. The accuracy of AK is, according to the Waste Acceptance Criteria, to be verified on a waste stream basis, although AK is also used to define waste streams. How accuracy should be determined is not specified in the Waste Acceptance Criteria. However, DOE has established Data Quality Objectives for AK as required by the HWFP (2003; Attachment Bat. The following is an excerpt from the State of New Mexico HWFP (2003; Attachment B3, Section B3-9~: ~Polychlorinated biphenyls are no longer listed in the HWFP as prohibited items; however, DOE is required to track their presence according to EPA's authorization for WIPP operation as a chemical waste landfill. 91n the case of newly generated wastes, it is likely that the generators' quality assurance programs will be approved by WIPP prior to generation of the waste.
Transuranic Waste Characterization Program To ensure that the acceptable knowledge process is consistently applied, the Permittees shall require sites to use the following definitions when complying with the data quality requirements for acceptable knowledge documentation: Precision- Precision is the agreement among a set of replicate measurements without assumption of the knowledge of a true value. [..] · Accuracy Accuracy is the degree of agreement between an observed sample result and the "true" value. The percentage of waste containers, which require reassignment to a new waste matrix code, and/or designation of different hazardous waste codes based on the reevaluation of acceptable knowledge and sampling and analysis data will be reported as a measure of acceptable knowledge accuracy. [..] Completeness Completeness is an assessment of the number of waste streams or number of samples collected to the number of samples determined to be useab~e through the data validation process. t...] · Comparability Data are considered comparable when one set of data can be compared to another set of data. Comparability is ensured through sites meeting the training requirements and complying with the minimum standards outlined for procedures that are used to implement the acceptable knowledge process. [...] . Representativeness- Representativeness expresses the degree to which sample data accurately and precisely represent characteristics of a population. 49 There is great variability in AK accuracy (degree of agreement between observed measurements and the "true" valuer among sites. AK accuracy is calculated by comparing the EPA hazardous waste identification numbers (see the Glossary) determined by confirmation activities to those predicted by historical information. A recent DOE report documents AK accuracy results for waste from the Rocky Flats Environmental Technology Site and Idaho Engineering and Environmental Laboratory. This report shows high AK accuracy when compared to the data acquired through tests with some slight differences among sites (Kehrman and Most, 2003~.~° According to DOE, differences in AK accuracy are the outcome of the implementation of inadequate procedures rather than erroneous historical information. Therefore, it is unclear how AK accuracy varies among different waste streams and among different waste sites. 4~5 Characterization Costs DOE provided the following characterization cost information at the committee's request. According to a 2000 estimate in DOE's National TRU Waste Management Plan, the total cost of waste management beginning in 2001 for the generator sites is $6.2 billion (DOE-NTP, 2000~. These estimates do not include costs for work done prior to 2001. The predicted cost from 2001 of characterization and certification of both CH-TRU and remote-handled TRU waste is about $3.1 billion, or approximately 50 percent of the total budget for all sites. Waste characterization at the current level represents 16 percent of the estimated total WIPP costs of $19 billion (DOE- FSElS, ~ 997~. Table 4. ~ shows characterization activities, the percentage of containers to undergo these activities, and average cost estimates per container in the current CH- 4°NMED observed that AK accuracy results are based primarily on waste from Rocky Flats Environmental Technology Site, part of which was sent to Idaho (NMED, 2003c).
50 Improving the Characterization Program for Contact-Handled Transuranic Waste TRU waste characterization plan. The "life-cycle cost" of an activity is the product of the "average unit cost," the total number of containers, and the fraction of containers that require the activity. Most costs of characterization activities are self-explanatory and refer to Figure 4.~. Waste certification costs include data management and audit activities. Characterization support costs correspond to site activities related primarily to container handling during characterization. The Savannah River Site was able to account for this activity separately; other sites included container handling in the characterization costs. i The table shows that, by far, the most costly procedures in the characterization program are those that involve breaching or penetration of the container (e.g., solids analysis, visual examination of reirievably stored waste, and homogeneous solids coring and sampling). The cost of TRU waste characterization to date averages approximately $3,900 per container. This estimate is based on an assessment at those generator sites that are currently characterizing and shipping waste to WIPP. There is uncertainty and a great variability in costs of characterization activities among sites depending on the nature of waste streams and the volume (DOE-CABE, 2003~. Characterization of the waste that has been shipped to WIPP has cost $160 million so far. If the cost of characterization remains the same, then characterization of all of the remaining CH-TRU waste destined for WIPP (approximately 750,000 drums) may cost up to $3 billion. According to the cost analysis provided by DOE (DOE-CABE, 2003; page 23), tarn area where costs could greatly be reduced pertains to the number of times a drum is actually moved prior to shipment to WIPP. [..] It is estimated that as the characterization program matures at each site and the number of waste streams approved for disposal increases, the number of drum movements could be reduced by up to 50°/O. The committee discusses below the CH-TRU characterization program and proposes some opportunities for improving its effectiveness. This discussion is reflected in the findings and recommendations in Chapter 6. 4.6 Discussion: Lessons from Experience and Future Opportunities Shipment to and emplacement of more than 40,000 drums of TRU waste in WIPP after four years of operations is evidence of the acceptability to the regulators of the waste characterization program thus far. The opening and operation of the WIPP facility would not have been possible if DOE had not provided its regulators with sufficient information of acceptable quality, including waste characterization information. However, after four years of operations, there are lessons to be learned and, with the experience base steadily increasing as WIPP operations continue, opportunities for identifying characterization activities that are not necessary to protect human health and safety and the environment. Determining whether there are inefficiencies in the characterization program and what improvements can be made is a complex task. To perform this task, a structured and quantitative analysis of characterization activities, coupled with operational experience, can be used to identify which, if any, characterization activity produces information that is not used in decisions concerning waste handling, transportation, or disposal and if alternatives that are more cost-effective and result in the same, or greater, level of protection of human health and the environment exist.
Transuranic Waste Characterization Program 51 Table 4.1 Characterization Activities, Percentage of Containers Ultimately Emplaced in the Waste Isolation Pilot Plant Requiring Such Activity, and Average Cost Estimates Characterization Activity Percentage of Average Unita Average Cost Containers Cost (U.S. Containera Activity Dollars) (U.S. Dears Non-Destructive Assay ~ 00 840 840 Headspace Gas Analysis ~ 00 620 620 Real-Time Radiography 32.8 730 240 Visual Examination/Retrievably Stored 1.2 22,500 270 -' .' Visual Examination/Newly Generated 67.2 540 360 Solids Coring and Sampling 0.5 24,000 120 Solids Analysis 0.5 63,000 310 Acceptable Knowledge 100 87 87 Drum Venting 1.8 120 2 Level I! Data Management ~ 00 ~ 60 ~ 60 - i i- Gas Generation Testing for Transportation 9 670 60 Drum Age Criterion 68.7 46 32 Segregation or Rework 30 1,400 420 Waste Certification ~ 00 330 330 Characterization Support Activities ~ 648 52 Average Cost of Characterization per Container aThe average unit cost is the cost to characterize a single container. The average cost per container is the unit cost averaged on the number of containers undergoing a particular characterization activity. SOURCE: DOE-CABE, 2003. 3,900 This structured and quantitative analysis is the subject of Chapter 5 and leads to the committee's main recommendation (Recommendation 1~. In addition to supporting the proposed analytical framework, operational experience can be used to identify opportunities to improve the characterization program that are operational in nature, some of which can be instituted without regulatory approval, as discussed below. 4.6.1 Uses of operational experience While characterization information gathered to date at four sites cannot be directly extrapolated to other sites and to waste yet to be characterized, the operational experience accumulated during these first four years of WIPP activities provides a basis on which to evaluate whether improvements in efficiency and costs can be realized while continuing to protect human health and safety and the environment (see Finding and Recommendation 2~. Examples of uses of operational experience to evaluate and improve the effectiveness of the characterization program are the following: Experience can be used to estimate the value and extent to which each characterization activity provides information that is: ~ ~ essential to protect health and safety, 2) reclundant with other activities or with historical knowledge of the waste, and 3) used to make decisions about waste handling, transportation, or disposal at WIPP. This information would be of use in the structured and quantitative analysis of the characterization program described in Chapter 5.
52 Improving the Characterization Program for Contact-Handled Transuranic Waste . . Analysis of the characterization data acquired to date along with continuing the characterization of increasingly diverse waste streams could identify new opportunities to use statistical sampling (rather than 100 percent of the waste stream) or different methods to confirm AK to provide information that would be as protective of health and the environment as the current measurements (see Sections 4.6.2 and 4.6.3~. Experience provides a basis for "know-how" transfer from one generator site to others. The application and sharing of improvements in management methods acquired at generator sites thus far can achieve cost, schedule, and worker dose reduction across the DOE weapons complex (see Section 4.6. ~ . ~ ). Experience allows a better understanding of cost variability across the waste inventory and generator sites as well as a better understanding of the relative value of different characterization methods providing similar information (i.e., radiography versus visual examination). Understanding why characterization costs differ significantly from waste stream to waste stream and from site to site could also lead to better cost estimates for future waste streams (see Chapter 5~. Only the second of these four examples potentially leads to changes requiring regulatory approval. 4. 6. 1. ~ Operational experience has a/ready produced improvements in waste handling The first four years of operational experience have already benefited waste handling operations. Characterization activities involve significant handling and intermediate storage (staging) of waste containers. Each container is subjected to multiple analyses, most of which can be the basis for rejecting a container which then has to be set aside waiting to be reworked. Some analyses require temperature control and aging of waste, and most require special equipment with limited throughput, such as headspace gas sampling and analysis. These activities require moving waste containers from one characterization operation to another or the staging of waste containers in the proximity of characterization areas. DOE refers to this handling of containers during characterization as the "dance of the drums" (DOE-CABE, 2003; page 23~: Drums are moved multiple times for characterization for many reasons (e.g., when the drum needs to be separated from the batch because something is amiss with the data package, when a cirum fails a certification test, or when the assay is problematic). The drum then needs to be set aside until the issue is resolved, or the drum is reworked. Costs at [the Idaho Engineering and Environmental Laboratory] are $~.33 per movement. Costs at [the Savannah River Site] are $21.60 per movement. Both [sites; have independently estimated that drums were moved approximately thirty (30) times in the characterization process. At some sites, limited storage capacity and storage times (under current limitations of the generator sites' permits) result in further waste handling to and from storage areas between characterization operations. The Rocky Flats Environmental Technology Site has demonstrated that the system for handling containers throughout the characterization process can be streamlined as workers and management gained experience. Improvements in operations developed at this site have led to improvements in cost, schedule, and worker protection (Spears, 2003~. Such an improvement process might be applied advantageously at the other generator sites.
Transuranic Waste Characterization Program 53 4.6.2 Different approaches for different waste streams Transuranic wastes are generated at different times, in different ways, and have different properties and compositions. The quality of information available on each waste stream is particularly important because this information becomes part of AK and determines the extent of characterization activities necessary to confirm this knowledge. Some CH-TRU waste streams, by the nature of their generation, their physical and chemical properties, and other special circumstances can be shown not to require the entire suite of characterization activities that are currently being carried out. Experience has shown that, in some cases, it is possible to tailor the characterization program to specific waste streams thereby adjusting the extent of confirmation activities to the quality and type of the information available (see Finding and Recommendation 3~. For example, DOE has obtained an exemption from headspace gas sampling and analysis for thermally treated wastes at the Rocky Flats Environmental Technology Site. To obtain regulatory relief from NMED, DOE provided a technically defensible case that showed how this particular waste stream could not contain any volatile organic compound. Opportunities for tailoring waste characterization to waste streams may be greater with to-be-generated waste. To-be-generated waste may be better characterized than existing waste because the characterization information can be collected at the time of waste generation under an approved quality assurance program. Future improvements in management methods, processes, and record keeping will also lead to better characterization information. Therefore, some to-be-generated waste may not require any, or as much, confirmation of the information collected about the waste. On the other hand, existing waste streams may have less detailed information available and require extensive characterization. As more waste is characterized, it may be found that current characterization methods or technologies may be unsuitable for certain waste streams. For instance, some existing wastes may pose characterization challenges and may need a stream-specific characterization process (see for instance Sections 2.3 and 2.4~. Special characterization techniques may be needed for non-destructive examination and assay to measure gas concentrations in the storage container, to handle large pieces of equipment (e.g., gIoveboxes with unique designs), or to address problems not yet encountered. Specialized operator training, new or improved equipment and facilities, special material handling and record keeping, and additional funding requirements are potential challenges that may have to be addressed. Changes to tailor the characterization program to different waste streams require regulatory approval. , 4.6.3 Different qualification methods for different waste information The confirmation-by-measurement method is applied systematically by DOE to qualify information to be used as AK, regardless of the extent of the information available or the origin of the waste. As experience continues to be gained, there may be future opportunities to take advantage of: 1) a statistical sampling program rather than 100 percent confirmation activities, or 2) the three other methods allowed to qualify AK (i.e., peer review, corroborative evidence, and qualification of another quality assurance program; see Section 4.4.2~. Applying statistical sampling rather than 100 percent confirmation to certain waste streams has already led to increases in program efficiencies. For example, as noted in Section 3.3.2, DOE has already successfully obtained a change to the HWFP that reduced the number of waste containers to undergo visual examination as a quality control check on radiography results, thereby saving more than $19 million.
54 Improving the Characterization Program for Contact-Handled Transuranic Waste The larger the number of containers included in a particular waste population to be sampled, the greater the potential increase in the program efficiency. As noted in Section 3.4, in the Certificate of Compliance application for WIPP, DOE identified 569 waste streams, while EPA sorted WIPP waste inventory by volume into 10 classes. In the HWFP. NMED identified ~ ~ Eves of waste streams decendina on the main matrix ,, ~ _ e ~ ~ ~ ~ . · ~ ~ I d · d · d ~ I do- d component. It too many streams are defined, the opportunities to use and benet~t from a statistical approach are diminished because the population to be sampled within each stream is smaller. At the limit, if each container is its own waste class, no statistical method for that class can be used. However, defining the population loosely to be all-inclusive could also be misleading. For instance, if a population to be sampled is defined to include both to-be- generated and existing waste (assuming the lager has poor historical information available), then statistical sampling methods would hardly represent the population. To ensure representativeness, the statistical sampling approach could apply to increasingly inclusive waste populations possibly followed by either decreasing sampling rates as experience is gained (and appropriate performance is documented) or increasing sampling rates if information is found to be inaccurate. Future experience with to-be-generated waste may show that it is possible to use AK for selected wastes without the need for confirmation. This can be done by managing and recording what is put into the containers in compliance with the approved CH-TRU waste characterization plan and by following an approved quality assurance program (see Findings and Recommendations 3 and 4~. Similarly, for existing waste that needs to be repackaged, if the appropriate characterization activities are performed during packaging under a regulator-approved program, they shouIcl provide AK-qualifiecl information without the need to open containers for visual examination or headspace gas measurement. Previous attempts by DOE to use qualification methods other than confirmatory measurements were not successful. DOE adempled to demonstrate that non-destructive assay measurements coffected for safeguard reasons on a particular waste stream at the Rocky Flats Environmental Technology Site could be used as corroborating evidence or as a qualified quality assurance program in lieu of WIPP-certified non- destructive assay data. About 4,000 drums had already been measured individually with a non- destructive assay system, which collects information on plutonium, americium, and uranium-235 for safeguard purposes. The Rocky Flats Environmental Technology Site measured the same population with a WIPP-certified system and made a statistical argument (based on the first 1,000 drums) that the total plutonium in the waste stream as predicted from the safeguards non-destructive assay was within ~ percent of that predicted by the WIPP-certified system. EPA dicl not accept safeguard data as a qualifying method because the data did not provide information on all 10 radionuclides listed in the Compliance Certification Application (see Appendix C). EPA also rejected this qualifying method for containers with less than 0.5 grams of plutonium, the lower detection limit for safeguard data. Also, the New Mexico Environmental Evaluation Group notes that several measurements accepted by the DOE's internal safeguards program were found to be significantly in error when containers were re-measured using WIPP-certified instruments (EEG, 2003b). DOE is currently evaluating opportunities for using peer review as a qualification method for existing information. For example, DOE has proposed to EPA that staff of the Los Alamos National Laboratory conduct a peer review on the seated sources stored at this site, for which, according to DOE, extensive documentation is available. These
Transuranic Waste Characterization Program 55 sources also need to be repackaged before shipment; therefore, the information collectecl during repackaging, along with peer review of historical knowledge, may not need any confirmation by measurement. Changes to confirmation activities require regulatory approval. 4.6.4 Importance of effective communication Experience shows that stakeholders,44 not only in New Mexico, but also in states generating waste and in corridor states, have concerns about WIPP-related operations. Since 1971, when focal officials in CarIsbad began advocating the development of the nation's first underground waste disposal facility in their area, local and state officials, citizens, and organizations have been involved in policy making about the WIPP site (Fleck, 2002~. As plans for a repository acivancecl, interest in WIPP expandecl to include officials and citizens along potential waste transportation routes in other regions of New Mexico, in states where DOE production facilities are located, and along transportation corridors. Although there has been broader public acceptance of the WIPP facility over time,42 there continue to be concerns about characterization-related activities and transportation (SRIC, 2001a; UNM, 2001; Daniels, 2003~. Members of the public are concerned about DOE's reliability in adequately protecting human health and safely, particularly in the event of an accident. Concerns about transportation include the use of uncertified characterization procedures; the safely of shipping containers; and the safely of transportation routes. A transportation protocol agreement has been signed between DOE and some of the corridor states reflecting the desire to ensure safe and uneventful shipments of waste to WIPP (see Sidebar 3. ~ ). During open meetings in CarIsbad and Santa Fe, the committee heard concerns about waste characterization from members of stakeholders organizations43 including the following:44 Rationale for proposed permit modifications is lacking (Nuclear Watch of New Mexico, 2003~. DOE permit modification requests are frequent and of poor quality (SRIC, 2002; Petrie, 2003~. There is a lack of transparency in the clecision-making process (SRIC, 2001b; Arends, 2003; Hancock, 2003; Peirie, 2003; Reade, 2003~. Internal drivers for DOE's cleanup program may lead to a reduction in characterization activities necessary for protecting public and worker health in order to save money (Petrie, 2003~. Less stringent characterization activities could increase potential radiation doses received by the public (Reade, 2003~. 44The term "stakeholders" indicates local officials and interested and affected members of the public in New Mexico, waste generator states, and corridor states. 42The University of New Mexico has been tracking public opinion since 1990 (UNM, 2001 ). 43As others have noted, most people who comment publicly about WIPP in New Mexico are members of existing stakeholder groups (Phoenix Environmental and Envirolssues, 2001; Drew et al., 2003~. 44The committee's understanding of the concerns of citizens and officials about characterization activities is based on presentations to the committee and on published documents (e.g., public comments on HWFP modification requests), not on an independent study conducted by the committee.
56 Improving the Characterization Program for Contact-Handled Transuranic Waste Changes to the waste characterization program may result in a decrease of regulatory authority by EPA and NMED (Peirie, 2003~. Communities near generator sites are concerned about risks to site workers; risks of storing waste at the sites; costs; and delays in moving waste out of their sites. Representatives of Citizen Advisory Boards from nine DOE sites prepared the following recommendations for DOE during a recent conference on TRU wastes (CAB, 2003~: ~ . . Characterize TRU waste as required to reduce risk and minimize transportation and handling of the waste, while making the process cost-effective. Streamline TRU waste management by accepting demonstrated process knowledge for TRU waste characterization. Evaluate the concept of one or more locations to characterize TRU waste for WIPP disposal. Finish the analyses and make a decision with adequate public involvement regarding where to characterize TRU waste for disposal. Several law suits against DOE involving generator or corridor states on matters related to WIPP were filed in 2003, reflecting focal group's concerns with the shipment and storage of out-of-state wastes to their site (Ashton, 2003; Mulick and Stang, 2003~. For example, in Washington State, there was concern about the Hanford Site receiving TRU wastes from the Badelle Columbus Laboratories site in Ohio for characterization before being shipped to WIPP (Mulick and Stang, 2003; Stang, 2003~. The state filed a lawsuit against DOE to reach an agreement on an accelerated shipping schedule for Hanford waste to WIPP, in exchange for storing and characterizing waste from other sites. Experience has shown that effective, transparent communication and the use of the established regulatory processes to make changes to the characterization program can help build cooperation and confidence among all parties (see Finding and Recommendation 5 and 6~. The lack of public accessibility to characterization records and the WIPP Waste Information System database is a frequently-expressed concern among stakehofJers. WIPP stakeholders have also publicly commented on the lack of information on proposed changes to the characterization program. Records of changes to the WIPP program show that regulators granted modifications to the authorization documents only after extensive communications and data exchanges with DOE staff, and after DOE provided a defensible technical analyses to show that proposed changes do not weaken protection of the human health and safety and the environment (see Section 3.3~. The New Mexico Environmental Evaluation Group's independent evaluations have contributed in building effective communication and transparency. This group provides technical input and oversight to DOE about WIPP issues, including transportation, and helps in conveying technical information to stakeholders and the general public. The quarterly meetings between DOE, NMED, the New Mexico Environmental Evaluation Group, the New Mexico Office of the Attorney General, and interested members of the public are an example of DOE's efforts to maintain communications and address concerns. Changes in the communication and outreach efforts of the program do not require regulatory approval. Experience in other waste 45An agreement was reached in October 2003 by establishing a legally binding schedule for the removal of TRU waste from the Hanford Site in exchange for accepting TRU waste shipments from Ohio.
Transuranic Waste Characterization Program 57 disposal programs has shown that effective communication with stakeholders and regulators as well as transparency can help to reduce or mitigate the lack of trust, avoid charges of secrecy, and possibly lead to greater tolerance of changes, where warranted (NRC, 2003 and references therein). Using operational experience is only one of the keys to improving the program. The uniqueness of certain sites or waste streams does not always allow taking acivantage of past experience. Moreover, changes to the characterization program may have policy or societal impacts that need to be considered prior to submitting a permit modification request. A structured and quantitative analysis of the linkages between risks, benefits, and impacts of characterization activities along with analyses of past and future waste inventory characteristics is needed to arrive at a flexible waste characterization plan program that can take into account the variability of sites and waste streams, allowing for more efficient and effective waste characterization operations as well as communication among all parties (see Findings and Recommendations).
