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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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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
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O ~
~ 0
LL
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— O
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THE NUCl~:AR WEAPONS COMPLEX
15
14
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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
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z
o
In
CC
60
40
20
THE NUCl~:AR WEAPONS COMPLEX
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1.2 <1 <1
1983 1984 1985
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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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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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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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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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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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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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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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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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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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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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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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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:
wear respirators
