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4 Safety INTRODUCTION From the perspective of conventional industrial safety, all the DOE nuclear facilities have excellent safety records. There are, however, other less conventional hazards at the weapons facilities, stemming from the handling of radioactive and fissionable materials, and these hazards are difficult to evaluate by the usual criteria of industrial safety. The most important of these is the exposure of personnel to radiation, both internally and externally. With few exceptions~ne being nuclear medicine~he hazards of handling radioactive materials are unique to the nuclear industry. Another unique hazard of fissile materials is the possibility of a criticality accident, i.e., the attainment of a self-sustaining nuclear reaction because of the inadvertent accumulation of too much plutonium or uranium-235 in an unfavorable configuration (see Appendix C). Criticality control has received strong emphasis at most sites, to good effect. Considering the large quantities of fissile material handled, the number of criticality incidents at processing facilities has been low (see Appendix C). The Department has adopted and seeks to apply all the safety and heals standards of the Occupational Safety and Health Administration (OSHA). In addressing radiation hazards, DOE has generally adopted the recommendations of the International Council on Radiation Protection (ICRP). However, DOE's enforcement of compliance with standards, from whatever source, is not consistent across the complex, and appears in some cases to be left largely up to the contractors. 54
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SAFEn 55 This chapter includes a variety of observations and recommendations concerning the diversity of hazards arising from the operation of the complex. Clearly, some conditions are more serious than others. The committee believes that a particular sense of urgency Is warranted in connection win fire safety, the handling of cyanide solutions, and the overreliance on respirators. We recommend prompt attention to these matters by DOE and its contractors. INDUSTRIAL SAFETY The weapons complex engages in many traditional industrial operations, such as metal fabrication, chemical processing, and electronic assembly. These operations can be evaluated by standards of conventional industrial safety. In 1986 the number of lost workday cases because of injury per 200,000 man-hours was 2.9 for all industry and 1.1 for the chemical ~ndus~y, but only 1.0 for the DOE plants (National Safety Council 1987~. This exemplary performance can be attributed to the strong emphasis placed on industrial safety by the DOE contractors. The safety performance for radiation protection of personnel is well within the standards established by DOE Order 5480.11 and the ICRP guidelines. Radiation safety performance has improved considerably over He past 20 years, as indicated by the substantial reduction in the total dose received by employees with an exposure greater than 1 rem (see Figure 4.1~. During this period, the number of employees in the complex has been relatively stable. As would be expected, the highest average exposures, within all DOE operations, are in the fields of fuel fabrication, reactor operations, fuel processing, nuclear components fabrication, and waste handling. For employees with a measurable exposure working in these areas, the average dose in 1987 ranged from 155 to 267 mrem, depending on the area (Pacific Northwest Laboratory 1989~. Analogous exposure averages are slightly higher in the commercial nuclear electric power industry, but the comparison is complicated by the different operations and opportunities for exposure (e.g., steam generators) in the private sector. In the following pages we note some examples of hazards that in our view deserve increased attention. Inhalation of Radioactive Materials Conclusion Some facilities in the complex are contaminated. As a result, production workers need to wear respirators routinely as a means to prevent inhalation of radioactive contaminants. Plutonium, when inhaled, is an extremely toxic substance. Consequently, a central objective of industrial hygiene in the nuclear weapons complex is the prevention of exposure to respirable plutonium. Ideally, this objective is met by
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56 z llJ J TIC in ~ O O ~ ~ 0 LL > ~ — O ~ — o THE NUCl~:AR WEAPONS COMPLEX 15 14 13 12 11 10 8 6 5 4 3 2 tlL-n - ~ 1 ~,n,u,tI,n,u,I,I,t,~1 I ~ F10 j] ~ ~ ~ ~ ~ O ~ ~ ~ ~ ~ ~ ~ ~ O (D co CO CD (80 ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ 0 ~ as as 0 as a) a) car as a) ~ a) or ~ as a) a) as a) ~ a) as a) O5 (* a) as YEAR 1~ Figure 4.1 Total collective dose equivalent for all DOE-DOE contractor employees who received an exposure greater than 1 rem, 1965-1987. adopting operating practices and contamination controls to avoid the need for breathing apparatus, such as respirators or supplied air, during routine production activities and most maintenance procedures. Most sites within the complex have reasonably effective control programs, so that the use of respirators is reserved for emergency situations only, and supplied air is required only during certain maintenance procedures. In the event of an emergency, workers don respirators for protection while they leave an area. In some exceptionally well run facilities, such as Building TA-55 at LANL, it is deemed unnecessary for visitors to carry respirators. At two sites that we visited, however, respirators were improperly used. In the plutonium production areas at the SRS, production workers are required to wear respirators whenever they are working in glove boxes as a precaution against pinhole leaks in gloves or other minor leaks. In our view, the mandatory use of respirators purely as a precautionary measure is unnecessary and counterproductive. Pinhole glove leaks can be Neatly reduced, if not completely eliminated, by frequent inspection and radiation monitoring and by establishing a routine replacement schedule. Respirators are uncomfortable and impair employee alertness, efficiency, verbal communication, and morale. The risks from their routine use appear to us to outweigh the marginal protection they offer against potential minor radiation leaks.
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SAFETY 57 The attitude toward radioactive contamination control at Rocky Flats is unique in the DOE complex. Some work areas are perpetually contaminated, and some production operations are conducted In a manner that makes contamination control virtually impossible. For many years there has existed et Rocky Fiats a"respirator culture" a feeling that as long as workers wear respirators, it is unnecessary to seek to maintain a contamination-free work area. The approach has led to sloppy operating practices. The biggest problems at Rocky Flats are in Building 771. The high contamination levels there are not attributable solely to age, because the facility has been extensively refurbished over the past 6 years. One of the difficulties is the practice of conducting maintenance and production operations simultaneously; as a result, production workers frequently have to wear respirators for as much as 4 hours per shift Even in the absence of maintenance activities, contamination is prevalent, and workers have to wear respirators for 2 or more hours per shift. The overreliance on respirators has several negative consequences in addition to those listed above. Respirators place a strain on the lungs and increase fatigue. But perhaps their most serious disadvantage is that they engender a false sense of security a feeling that, so long as a respirator is wom, there will be no radioactive inhalation problems. The fallacy of this conclusion is demons~a~d by the experience at the ICPP at the INEL. In 1983 and 1984, the committed lung dose for workers at ICPP was more than 100 man-rem (see Figure 4.2), even though the wearing of full-face respirators in the contaminated work areas was required. In 1985 the lung dose dropped to 1.1 man-rem as a result of changes in work practices and by requiring the use of supplied air in place of respirators in certain operations. In our view, the pattern of use of respirators at Rocky Flats is an indication of the failure of production, maintenance, and housekeeping procedures. Maintaining an uncontaminated working environment is a more effective strategy than protecting workers in a contaminated environment. Recommendation The Department of Energy should discourage routine reliance on respirators in favor of engineered controls and operating practices that prevent contamination of the workplace. Respirators should be necessary only in emergency situations. Contamination in Ductwork Conclusion Sizable accusations of plutonium exist in the exhaust ducts at some buildings that process the metal. An estimated 11 kg of plutonium has accumulated in the EN exhaust system, the 26-in. process vacuum piping system, and the stack manifold at Hanford's Plutonium Finishing Plant (Scientech Inc. 1989a). Some of the contamination is downstream of the high-efficiency particulate air (HEPA) filters, so that if the material were upset or dislodged, it could be released to the atmosphere. Kilogram
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58 100 80 a: z o In CC 60 40 20 THE NUCl~:AR WEAPONS COMPLEX o 1.2 <1 <1 1983 1984 1985 I_. 1986 1987 1988 YEAR FIGURE 4.2 Committed lung dose equivalent; SO-year collective dose equivalent assigned to year of intake. quantities of plutonium have also accumulated downstream of the HERA prefilters in an exhaust duct of Building 771 at Rocky Flats (Scientech Inc. 1989b). The hazards of accumulation are many, since any number of circumstances could cause a breach in integrity of the ducts. Earthquakes are an obvious dislodgment mechanism, as are releases resulting from corrosion, improperly performed maintenance operations, carelessness, or fire. Moreover, undesirable exposures of workers to neutrons may result even in the absence of a release, particularly if the ducts contain significant quantities of plutonium fluorides. Also, the threat of a criticality event makes it unwise to have accumulations of unknown quantities of plutonium in unknown configurations. At Hanford an action plan has been developed, that calls for removal or cleanout of portions of the vacuum and exhaust systems in a pilot program commencing in FY 1989 and continuing through FY 1993. The program, which is expected to remove art estimated 6 kg of this plutonium, should be implemented soon and accelerated if possible. The cleanup should then be extended to the rest of the ventilation system. The same problem may exist at other facilities as well. Even PAPA filters do not provide absolute barriers, and in any event, downstream contamination may occur when filters are changed. It thus seems prudent to assume that the ventilation
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SAFEn' s9 systems In other plutonium processing buildings the FB line at SRS, Building 332 at LLNL, and Building TA-SS at LANL, for exampl~may also contain plutonium in varying amounts. In addition, exhaust ducts in buildings processing uranium and beryllium could well contain unacceptable concentrations of these hazardous materials. A strategy for dealing with this potential contamination is needed. Recommendation The Department should develop and implement a plan to assess accumulations of plutonium, americium, uranium, and beryllium in the ventilation systems of relevantfacilities and, in cases where significant quantities are found, institute cleanup or removal programs. Convendonal Industrial Safety Practices Conclusion Some DOE contractors have indicated that criticality is their primary safety concern, awl nuclear safety has been greatly emphasized. There are indications, however, of lack of adequate attention to conventional industrial safety practices. Some sites have a strong nuclear safety program, and the results are commendable. Most processing equipment is geometrically safe and physical constraints are provided to maintain safe spacing of fissionable material during transport and storage. Such stringent controls are lacking, however, in some areas involving conventional herds. For instance, we observed the following conditions and practices at the Y-12 Plant. These observations, some of which are anecdotal, are based on circumstances perhaps transient that existed at the time of our visit. They are not intended as a condemnation of this site in particular, but rather as examples of the types of conditions that could exist and should be eliminated— at all facilities. · Cyanide solutions are handled in a cavalier manner in the Plating Shop. Gold plating operations with an acid cyanide bath are performed not in a full enclosure, but using only a fume hood or a horizontal duct just above the plating bath. This practice appears to be inadequate because cyanide salts in acid solutions are converted to hydrogen cyanide (HCN), a very toxic gas. In fact, because it is chemically such a weak acid, HCN is the primary cyanide species even in mildly alkaline solutions (up to pH 9~. Its high solubility in water precludes a massive release of HCN gas into the atmosphere from the acid solutions commonly used in weapons production, but it is unwise ~ conclude that this reduces the need for adequate ventilation. · There are no high-efficiency particulate air filters on the exhaust system from the incinerator in the enriched uranium recovery facility (Building 92061.
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60 THE NUCLEAR WEAPONS COMPLEX Instead, the exhaust system is fitted with bag filters. Regardless of whether the uranium release is within regulatory guidelines, this practice is contrary to the "as low as reasonably achievable" (ALARA) concept; emissions could be reduced by replacing the bag filters with HEPA fetters. Less serious were several observations indicative of poor housekeeping. · Storage practices were poor. Cartons and bags of chemicals, some toxic and some leaking onto the floor, were stored on pallets in work areas and near high-trafD~c routes. In the loading area, large arrays of gas cylinders were stored without adequate anchoring, and some SS-gallon drums were stacked precariously. · some Moors were oily. In the pressing area of the lithium facility, the footing was excessively slippery, particularly when shoe covers are worn. In the beryllium and depleted uranium machining areas, lathe coolant was spilling onto the floor. Rigid plastic housings similar to those on the enriched uranium lathes are needed. Recommendation While maintaining its commendable emphasis on nuclear safety, DOE and its contractors should reassess conventional safety programs and institute an upgrade to bring them on a par with nuclear safety. Sitewide Emergency Control Centers and Local Monitoring of Safety Systems Conclusion Sitewide emergency response plans do not electively make use of knowledgeable personnel working within the various buildings. Monitoring of safety systems in buildings where a serious emergency roughs occur is inadequate. A number of sites have sitewide emergency control centers designed to respond to plant emergencies: the Rocky Flats Plant and ICPP at MEL are two examples. Such centers are necessary, but in some cases they are inadequate. For example, the ICPP center has the disadvantage of being near and downwind of an HE storage tank, so that it would be uninhabitable in the event of a major rupture or spill at the tank. In general it is not possible for the staff of a sitewide emergency control center to have specialized knowledge of the operations and hazards in all the buildings at the site. Only persons permanently assigned to a building are likely to possess the necessary detailed information, such as current configurations and inventories. Therefore, in any building where an emergency might have serious immediate or long-term consequences, the emergency response team should be made up of people who work in that building. The teams should be linked to the site emergency control centers through procedures clearly understood by all concerned as laid down in the emergency response plan.
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SAFEnr 61 A related issue is the close monitoring of safety systems within each building to assure prompt response to abnormal conditions. In addition, operations should be contingent on Be operational status of all essential safety systems. These systems might be measuring parameters such as ventilation flows and vacuum levels, the integrity of HERA filters, air contamination, steam pressure, or temperature stability. Centralized monitoring is warranted to assure that all safety systems are operational. Within each building the personnel responsible for the localized monitoring of safety systems would be valuable additions deco He in- building emergency response tens described above e Recommendation Any building where an emergency might have serious consequences should have an emergency response team that includes employees who are knowledgeable about that building. In addition, all essential safety systems within each building should be continually monitored to ensure that they are operating correctly. [IRE SAFETY The fire protection program within the complex is multifaceted. It encompasses the following elements: safe operating procedures and administrative controls to minimize fire hazards; the design of structures and production systems to mitigate the effects of foe; the testing and maintenance of fire protection systems to assure their performance; and the organizing, equipping, and Wining of site fire departments to assure a prompt and effective response to any fires. Written guidance covering many aspects of this program is contained in DOE orders and other criteria supplemented by industry standards and the practices of contractors. The individuals responsible for implementing the program are a diverse group of knowledgeable and experienced fire protection specialists. Conclusion Fire protection within the complex is, to a significant degree, addressed on a site-specific basis, and decisions concerning individual issues are made by the local representatives of DOE or its contractors. Little coordination among sites was apparent, and an insignificant [ever of headquarters oversight to ensure consistency was evident. The inconsistency has resulted in a number of instances of fire safety issues being unevenly addressed across the complex or not addressed at all. This tendency has been aggravated in some cases by a lack of clear, explicit criteria from DOE concerning the design of fire protection features or the implementation of procedures to deal with fire protection issues unique to the weapons complex and not adequately encompassed by industry standards, such as the National Fire Protection Association (NFPA) Fire Codes. Despite these limitations, DOE and its contractors ha Ye achieved a number of noteworthy accomplishments. Among them are well-equipped site fire departments with a fleet of modern mobile apparatus and highly trained fire fighters. In addition DOE property losses due to f res are low.
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62 THE NUCI~AR WEAPONS COMPLY The Deparunent's fire protection program criteria, as delineated in the venous orders and other internal documents, provide acceptable statements of overall fire safety philosophy within the weapons complex. This general guidance is supplemented by reference to industry standards such as the NF-PA Fire Codes. Unfortunately, industry codes do not adequately address several special requirements of the weapons complex that are not found in private industry. It is especially important that hazardous materials not be transported by f~e-generated flow fields; carefully designed ventilation systems can help minimize this threat. Other special requirements include glove box fire protection, fire-safe ventilation in a radiation environment, emergency egress from secure areas, and the need for mobile fire apparatus at individual sites. The lack of special criteria has resulted in ad hoc approaches to fire protection across the complex. The Deparunent's fire protection program criteria require that fire suppression systems be installed in locations where a fire could cause damage to equipment that would interrupt process operations for longer than 6 months. At the Rocky Flats and Y-12 plants such "single-failure" areas were routinely protected by automatic or (on a limited basis) manual sprinkler systems. At the remaining sites we visited, there were locations of this type that were vulnerable to fire drainage and not adequately protected. We were also concerned about locations where a single fire could damage systems necessary for the safe operation of the production facility. There was no evidence that DOE or contractor fire protection criteria comprehensively address the provision of adequate fire protection for these locations. Moreover, there was no evidence that a systematic effort was being undertaken to identify such locations for future safety enhancements. Fire protection design for ventilation systems within materials processing facilities varied widely among the sites we visited. The specific focus of our efforts was on filter plenum design. At Rocky Flats, the contractor has applied internally developed fire protection design criteria that are both explicit and conservative, featuring multiple stages of fire safety features. At other sites, more limited protection was observed. In some instances, only fire detectors were installed in return air plenums, in accordance with NFPA Standard No. 90 A. At other sites, fixed manual or automatic fire suppression systems were provided within filter plenums, depending on the size of the plenum. With the exception of several recently constructed buildings, most of the structures and mechanical systems observed within the complex were erected and installed many years ago, and they were not designed to withstand the effects of the more severe earthquakes that might occur in their regions. Consequentlv' passive and active fire protection features may not be operable following a seismic event. Manual fire-fitihung efforts would be hampered by the unavailability of water for hose streams and the distinct possibility of simultaneous multiple alarms from malfunctioning automatic systems. However, no contingency plans had been formulated by DOE or its contractors at any site we visited to respond to . . .. . postse~smlc conditions.
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SAFEn 63 At three sites~he Y-12 Plant, INEL, and SRS we investigated the adequacy of fire department radio communications and found that, at all three, structural interference to communications was acla~owledged as a problem. Specifically, within certain areas of some of the larger facilities the f~re-fighting attack teams would not be able to communicate with each other or with supporting personnel because of the steel structural elements. At SRS, telephones were offered as a compensatory feature, but their viability in a smoke-filled environment could not be confided. A related issue is the availability of a dedicated radio frequency for fire department use, which offers the advantage of no nonessential conversational "clutter" during a fire or medical response. The fire department at MEL has such a radio frequency, but at the Y-12 Plant, the fire department has to share its radio communications capacity with other site organizations. Variations in Operational Approach Fire protection systems designed to mitigate the consequences of a fore are not comprehensively or uniformly covered by operational safety requirements (OSRs) throughout the weapons complex. OSRs are facility-specific procedural requirements covering many different systems. For some critical mechanical and electrical fire safety systems, they mandate that alternative compensatory actions be available if those systems become inoperable. Based on interviews conducted with the fee protection staffs, it appeared that the Hanford Site has the most fire protection systems covered by OSRs. Most active fire protection features, such as fire detection and suppression systems, are covered at Hanford by OSRs. However, fire barriers, including fire doors and dampers necessary to restrict the spread of fire within a facility, are not covered by these requirements. The applicability of OSRs to fire protection features at other sites within the complex varies considerably; indeed, at the Y-12 Plant we were informed that no fire protection systems are covered by OSRs. Based on interviews with DOE and contractor staff, we concluded that the fire protection organization's involvement (including that of the fire department) with emergency planning and preparedness at both Rocky Flats and SRS was well handled. The involvement included off-site organizations, DOE and contractor personnel, and the Frequency of drills and simulation of accident conditions. At the Y-12 Plant, although drills were conducted, realistic conditions were not simulated and the drill frequency was lower than those at other sites. Fire Protection Audits The Department's contractors are responsible for performing periodic fire protection audits. Local DOE fire safety professionals also audit the performance of contractors. DOE headquarters appears to have a minimal role in this process. We investigated the adequacy of contractor fire protection audits, looking at
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64 THE NUC' FAR WEAPONS COMPLY frequency, comprehensiveness, report format, and the use of DOE criteria. We concluded that at most sites the audits were adequate, except for the coverage of critical single-failure points discussed above. At the Y-12 Plant, however, there was evidence that existing DOE fire protection criteria were not being used in the evaluation of site facilities. At Rocky Flats, in part because of the personnel shortage, audits were significantly less frequent and less detailed than those at other sites. Personnel and Equipment The organization, staffing, training, and equipment of the site fire deparunents were, with few exceptions, superior. Each site benefited from a fleet of modem mobile apparatus, including support vehicles equipped to deal with most contingencies. The fire fighters appeared to be motivated, and they had undergone extensive training. Our only criticisms concern the absence of criteria governing the selection of vehicle types, the siting of fire stations, and the determination of minimum personnel levels. Personnel levels, for both fire protection engineers and fire fighters, are adequate for current needs at Hanford and the Y-12 Plant. At INEL and SRS, some vacancies in the contractor fire protection engineering staff have had an adverse impact on the few protection program, reducing the frequency of periodic audits. Personnel shortfalls are most severe at Rocky Flats. No DOE fire protection engineer is available, and only one contractor fire protection engineering position is currently filled. Several additional positions are required to fully staff the site fire department. Funding for modifications related to fire safety was adequate at most sites. Fire protection line items are in the budgets at the Y-12 Plant, INEL, and SRS, but not at Hanford or Rocky Flats, where some needed safety improvements were delayed because of insufficient funding. Recommendation DOE should develop specific engineering design criteria and administrative guidelinesforfire safe tyfor application to the special problems of the complex. These criteria and guidelines should benefit from input from the individual sitefire protection steps and allowfor diversity of application depending on local conditions. DOE headquarters should more actively audit the sites to assure that criteria are being implemented in an effective manner to achieve a consistent level offire safety throughout the complex. CRITICALITY SAFETY Conclusion Department of Energy contractors are generally providing effective criticality controls for operations with fissile materials. A shortage of criticality
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SAFEn' 65 safety personnel exists, and the future of the one remaining facility available for training in cnacaliry safety is uncertain. Current criticality safety practices in the venous DOE contractor organizations are generally outgrowths of the control systems established in the 1960s, following the series of criticality accidents between 1958 and 1964. Details have evolved somewhat differently for each contractor, as is probably appropriate; but in these organizations, the basic criticality safety standards are being met. These standards were developed by the American Nuclear Society Standards Subcommittee ~ and through Consensus Committee N-16 (American Nuclear Society, 1975-85~. These documents also provide the bases for the Regulatory Guides of the Nuclear Regulatory Commission Hat address criticality safety concerns. The Nuclear Regulatory Commission relies more heavily on these standards than does DOE.) Morover, under the sponsorship of the Nuclear Criticality Technology and Safety Project funded by DOE, annual conferences provide opportunities for discussions of problems that have been encountered, current practices, and changes that have been proposed in standards and DOE orders related to criticality safety. A concern recognized at most facilities was the difficulty of finding and training people for criticality safety assignments. Even to sustain the current efforts in ensuring criticality safety, DOE and its contractors will have to recruit and train personnel to produce experts in this highly specialized field. Training programs and facilities are obviously key to success in this area. Many of those who have served in this activity over the past 25 years gained their experience through work in the several facilities Rat were conducting measurements on critical assemblies. Today only two facilities of this sort exist, and the one at Rocky Flats is dedicated to the solution of problems related to production at Rocky Flats. The Los Alamos Critical Assembly Facility (LACAF) is the only remaining general purpose facility, and its assembly machines provide measurements in support of other contractors, in addition to serving Los Alamos' needs. The facility is also used for giving hands-on experience to students attending the 2- and 5-day classes in criticality safety conducted by the Los Alamos Criticality Safety Group. One other contractor, Martin Manetta, is sending new and less experienced criticality safety personnel to LACAF to gain the perspective provided by work in such a facility. Criticality safety practices today make great use of the large computer capabilities available in the complex. But such modeling efforts have their limits. Computer models must be carefully verified by experimental data. For example, it is important that statistical information arising from the experiments be correctly treated in the computer model. Moreover, wherever possible, computer~eveloped designs should be evaluated with experimental data. A revised broadly applicable set of such data has recently been published (fax ton and Provost, 1986) through the support of the DOE Office of Nuclear Safeness, now defunct. These data are predominantly related to aqueous systems containing enriched uranium or plutonium, although such other data as exist are included.
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66 THE NUC' FAR WEAPONS COMPLY For innovative designs and procedures, cnt~cality safety evaluations must rely either on newly acquired data or on large and uneconomic safety margins. As an example, pyrochemical operations, such as the direct induction of plutonium oxide to metal, are currently undertaken using small batches of fissile material. If the operation were to be scaled up, further experimental measurements on systems containing the fissile material and salts would facilitate process designs that are both safe and efficient. A capability to malce the necessary measurements must be maintained, or the ability to achieve process efficiencies with new technology will be reduced. In the absence of an or'~anizanon like the former Office of Nuclear Safety, DOE has no focus for conducting criticality safety measurements important to all nuclear facilities. DOE policies state that criticality accidents must be prevented, but the concomitant support is not always provided. In the distant past, contractors had the flexibility to assign resources to needed activities, and it was during these times that most of the data regarding criticality that we rely on today were generated. The number of critical experiments performed today is only a small fraction of the number earned out 25 to 30 years ago. This is partially due to the wealth of accumulated data, but it is also attributable to the increased complexity of regulatory requirements, limited funding, lack of a clear assignment of responsibility within DOE, and the fact that most of the "easy" experiments have been done. One of the working groups of the Nuclear Criticality Technology and Safety Project has developed a prioritized list of criticality measurements to be performed (Brown 1987~. The Department of Energy has recently char~red the Nuclear Criticality Safety Program Committee, composed of program officers involved with criticality. DOE has done well to form such a committee to study the questions of where responsibility for criticality safety should be assigned and what criticality experiments are needed. This is a good start toward rationalizing the organization and program for criticality safety in the weapons complex. Recommendation The Department should continue its effort to develop and implement a coherent criticality safety program. DOE must alleviate the serious shortage of technical personnel in criticality safety through an enhanced training program. SEISMIC SAFETY Conclusion Over the past decade, seismic design criterinfor new DOEfacilities have been consistent with state-of-the-art seismic requirements. But much of the construction of the DOE complex is old and predates a modern understanding of earthquake ground motion. Current DOE policies are not clear regarding the standards to which the older facilities should be heldfor the purposes of seismic
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SAFEn' 67 safety. The effort to improve the seismic capability of older structures is uneven across the complex. There is little or no communication between facilities concerning common problems. The linkage to the outside world is also highly variable, with some sites actively participating with the professional community and others remaining isolated. Among the safety issues that must be considered in the design and operation of weapons facilities is the response to ground shaking that may occur because of earthquakes. Modern building codes in the United States reflect the different earthquake probabilities in different parts of the country. For normal construction this practice is a successful one, producing buildings that, for the most part, perform extremely well during earthquakes. For buildings built before the formal adoption of earthquake zoning considerations, such as many of the DOE production facilities, good engineering practices provide a certain amount of earthquake resistance through general specifications and wind loading requirements. Nevertheless, older structures in which hazardous operations take place need to be carefully examined to assess effects of possible earthquake ground motion. DOE Practice Although the DOE facilities have not been subject to the same regulatory environment as the commercial nuclear industry, DOE has in fact followed nuclear industry practices for assuring seismic safety as they have evolved, particularly during the past decade. Thus recent construction by DOE reflects standards and practices that are consistent with developments in the commercial nuclear sector. A comparison with He criteria and analyses at nearby commercial nuclear power plants licensed by the Nuclear Regulatory Commission serves to demonstrate that DOE's recent approach conforms to standard modern practices. A major problem, recognized by all, is that many of the facilities in the complex are old and predate modern earthquake engineering practices. The performance of these structures must be evaluated in the light of modern understanding of earthquake ground motion. With such an evaluation in hand, needed modifications can be made to strengthen the structures or otherwise improve their performance, and strategies can be developed to minimize risk in the event of failure. Changes in other practices, such as anchoring and shelving, may also be indicated. Earthquake Criteria Each of the DOE facilities we visited seemed to have an adequate criterion for its "design basis earthquake." The criteria have resulted from a variety of studies, largely probabilistic, that have been sponsored by DOE over the past decade. In addition' some local DOE contractors have undertaken such studies independently.
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68 THE NUCl=AR WEAPONS COMPLEX The studies depend heavily on subcontractors for technical input to augment the small number of internal staff with earthquake engineering expertise. The Deparanent's weapons complex spans the entire United States and thus encounters the full range of earthquake possibilities. For example, the Savannah River and Oak Ridge sites are in the stable eastern seaboard region, which is characterized by infrequent earthquakes. Although infrequent, earthquakes in this region can be large, as evidenced by the Charleston, South Carolina, earthquake of 1886. A special problem with earthquakes in the eastern United States is that their association with faults is uncertain, making it impossible to predict with any certainty where they are going to occur. A good deal of research is being done in this area, however, and it was encouraging to see the Savannah River staff actively involved in it. SRS also has an active advisory committee, made up of university researchers, helping with local investigations, and there is a special budget allocation for such research. As a result, SRS appears to be following closely all recent technical developments related to earthquake phenomena in this region. Rocky Flats, Pantex, Sandia (Albuquerque), and Los Alamos lie in relatively stable regions. Earthquakes are infrequent, and their relation to geologically mapped faults is more predictable, permitting the use of conventional methods for specifying design earthquakes and ground motion. INEL and Hanford are located in the intermountain west, a region characterized by large earthquakes that occur with a frequency exceeded in the United States only in California. As a result, great attention is paid to earthquake phenomena, and there is an ongoing effort to learn more about the seismic potential of faults in the region. These facilities have established internal programs that use site contractor staff, as well as specialized investigations conducted by outside consulting firms. As in the case of SRS, at both INEL and Hanford outside advisory panels or other mechanisms are in place to ensure contact with the professional community. Lawrence Liverrnore National Laboratory is located in a highly active seismic region and has an outstanding internal capability in all facets of the science of seismology and of earthquake engineering. Upgrading Old Facilities Oak Ridge provides an example of the process being used for seismic review throughout the complex. The specific criterion for the design basis earthquake at Oalc Ridge is, of course, different from those at other facilities. Nonetheless, the analysis is typical of that used elsewhere. All major process facilities at the Y-12 Plant were built in the 1940s or early 1950s before seismic design of facilities became a requirement (see Figure 4.3~. For purposes of evaluation, two ground acceleration criteria were established: 0.08 g for facilities with a remaining life of 25 years and 0.12 g for those with 50
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SAFETY 6 — 5 — - ~ 4- a In o 3 3- 2- 69 10 Years > 10 Years old - > 30 Years old 1 l > 40 Years old 0 4 ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,~ 40 45 50 55 60 65 70 75 80 85 88 YEAR ACQUIRED FIGURE 4.3 Y-12 facility base: the age factor. years remaining. If a new major process facility were to be constructed in Oak Ridge today, it would most likely be designed for something between 0.15 g and 0.18 g. For companson, the design basis for He Clinch River Breeder Reactor, proposed to be located near Oak Ridge, was 0.25 ge This difference in criteria for plants in the same geologic province, with the same exposure to earthquakes, is not surprising; it reflects the fact that the consequences of an earthquake-induced accident enter into ground-acceleration specifications. Nonetheless, the use of an acceleration criterion as low as 0.08 g may be questionable. Without a detailed examination of the analysis of the consequences of failure of these older structures, it is not possible to determine whether the approach is sufficiently conservative. Further work is needed to justify this criterion. Given the great range in consequences and the variation in geologic conditions at the different sites, the committee is not in a position to recommend a general priority for seismic upgrading. The Department and its contractors have focused on seismic threats to buildings.
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70 THE NUCLEAR WEAPONS COMPLY The current effort is largely performed on ~ building-by-building basis. Insufficient attention is paid to seismic issues affecting systemic safety over the site as a whole, such as earthquake damage to emergency systems, communications, and fire-fighting capabilities. There appears to be a commitment from management to provide the resources necessary to identify problems. Where reviews identify minor modifications that can be made to improve earthquake resistance, they are implemented rapidDy. However, should major renovation be called for as a result of these reanalyses, it is not clear how priorities would be assigned. Currently, the emphasis is on safety of operation. That is, the analyses seek to assure that the damage will be sufficiently limited to prevent a major release of radioactive material. But even damage at an `'allowed', level could terminate operations indefinitely. In the future it may be necessary to add to the evaluations some cost-benefit considerations concerning the possible loss of production capability in the event of an earthquake. Recommendation The Department of Energy should develop improved guidelines for seismic review of older structures housing hazardous facilities. A uniform policy should be established that takes into account realistic estimates of remaining useful life and costs and benefits so that sensible assignment of priorities for seismic upgrading of older structures can be made.
Representative terms from entire chapter: