[Federal Register Volume 62, Number 103 (Thursday, May 29, 1997)]
[Notices]
[Pages 29118-29120]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-13977]


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DEFENSE NUCLEAR FACILITIES SAFETY BOARD

[Recommendation 97-2]


Continuation of Criticality Safety at Defense Nuclear Facilities 
in the Department of Energy (DOE) Complex

AGENCY: Defense Nuclear Facilities Safety Board.

ACTION: Notice; recommendation.

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SUMMARY: The Defense Nuclear Facilities Safety Board has made a 
recommendation to the Secretary of Energy pursuant to 42 U.S.C. 2286a 
concerning continuation of critically safety at defense nuclear 
facilities in the Department of Energy (DOE) complex.

DATES: Comments, data, views, or arguments concerning this 
recommendation are due on or before June 30, 1997.

ADDRESSES: Send comments, data, views, or arguments concerning this 
recommendation to: Defense Nuclear Facilities Safety Board, 625 Indiana 
Avenue, NW, Suite 700, Washington, DC 20004-2901.

FOR FURTHER INFORMATION CONTACT:
Kenneth M. Pusateri or Andrew L. Thibadeau at the address above or 
telephone (202) 208-6400.

    Dated: May 21, 1997.
John T. Conway,
Chairman.

Continuation of Criticality Safety at Defense Nuclear Facilities in the 
Department of Energy (DOE) Complex

May 19, 1997.
    In the first two or three decades following the Manhattan Project, 
nearly every laboratory of the Atomic Energy Commission (AEC) had an 
active program addressing some phase of the physics of neutron chain-
reacting systems. Each such study included a balance of experiment and 
theoretical analysis, as in common in engineering research. Some of the 
programs supported the design of nuclear weapons, some were directed at 
the design of nuclear reactors, and some were conducted simply as basic 
engineering research.
    As a result of these programs, expertise in neutron chain-reacting 
systems was widespread; there was an abundance of individuals skilled 
in achieving and controlling neutron chain reactions. These individuals 
usually became expert as well in methods of avoiding a chain reaction 
when this is not desired. The state of a self-sustaining chain reaction 
is commonly called ``criticality.'' Guidance by these knowledgeable 
individuals helped establish an admirable record of criticality safety 
in the many programs the AEC conducted with fissionable material. While 
occasional accidental criticality did occur at the peace of AEC 
activity, it seldom caused injury to workers, and never led to 
radiation affecting individuals off site. Furthermore, the last such 
instance of inadvertent criticality in the United States occurred about 
20 years ago.
    Some criticality research continued to replenish the supply of 
these experts through the era of the Energy Research and Development 
Administration (ERDA) and into the period of the Department of Energy 
(DOE), though at a steadily reduced rate. Today there is almost no 
theoretical research in criticality being conducted, although 
university courses continue to instruct students in the theoretical 
expertise that has already been developed. However, most of the early 
experts in criticality safety control were drawn from experimental 
research programs. For a number of years, the DOE complex placed its 
reliance for criticality safety on the diminishing number of such 
criticality control experts developed in earlier years. Recently, 
however, DOE has been forced to supplement that group with engineers 
trained on the job in the conduct of criticality calculations. The 
latter group contains few individuals who have conducted critical mass 
experiments. Thus collectively they have little practical experience

[[Page 29119]]

pertinent to avoiding chain reactions in nonreactor environments.
    In 1993, the Defense Nuclear Facilities Safety Board (Board) sensed 
that the source of experimental competence in prevention of inadvertent 
criticality was in danger of being lost entirely as a result of DOE's 
impending closure of this last critical mass facility in the country. 
That closure would have ended the hands-on education of new generations 
of scientists and engineers in the properties and behavior of critical 
systems. However, expertise in criticality safety will continue to be 
needed as long as fissionable material is used and stored. The Board 
viewed the end of experimental criticality studies as a threat to 
criticality safety in future DOE activities, and issued Recommendations 
93-2, which advised against such action. As stated in that 
Recommendation,

    The Board believes it is important to maintain a good base of 
information for criticality control, covering the physical 
situations that will be encountered in handling and storing 
fissionable material in the future, and to ensure retaining a 
community of individuals competent in practicing the control.

    The Secretary accepted Recommendations 93-2 on May 12, 1993, noting 
the importance of (1) improving and maintaining a criticality control 
information base, especially to support future operations in handling, 
processing, and storage or disposal of fissionable material; (2) 
retaining a cadre of individuals competent in practicing criticality 
control and safety; (3) continuing an experimental program; (4) 
continuing an education program for criticality safety professionals; 
(5) coordinating the criticality program among various users; (6) 
performing a criticality assessment with respect to defense nuclear 
facilities to determine the scope of current and future requirements 
for criticality experiments, predictability, and training, and (7) 
investigating the mission requirements, program funding, and landlord 
issues.
    Since Recommendation 93-2 was issued, DOE has made substantial 
progress in coordination and implementation of the criticality 
experiments program. Funding for the program has stabilized, albeit at 
a low level, and work has been initiated on a prioritized list of 
experiments. However, a basic set of problems continues to exist 
throughout the DOE complex with regard to criticality control. Among 
the problems are the following:
    1. In the past, it was found that only a few experienced 
criticality engineers were needed to guide criticality safety at even 
the most complex facilities. However, at the majority of DOE facilities 
where accidental criticality is currently a potential issue, the number 
of engineers assigned to criticality control is surprisingly large. The 
Typical criticality safety staff consists mainly of individuals who 
have no prior first-hand experience in criticality, and who have been 
trained on the job in analytical aspects of criticality control after 
being hire. They lack background in neutron physics on a fundamental 
level, and are not familiar with work on assemblies near the critical 
state, activities that would foster intuitive approaches to criticality 
control. Therefore, when faced with the need to determine what must be 
done to avoid a chain reaction, they most frequently fall back on 
complex multidimensional Monte Carlo calculations. Their use of 
simplified methods and their reliance on published data are minimal. 
The Board points out that complex analysis may be needed for some 
cases, such as those with difficult geometry, but such analysis is 
time-consuming and may dramatically slow preparation for the activities 
being evaluated.
    2. Operational practices at some DOE facilities place criticality 
control in a central position in operations, with the criticality 
engineer establishing certain aspects of operation for safety reasons. 
Effectively, the criticality engineer, with all the shortcomings 
described in 1 above, becomes the critical path for line management. 
This causes delays in the ability of the line management to develop 
overall safety requirements.
    3. In the past, most of the criticality safety data in guidance 
documents has been directed to activities involving production of 
nuclear weapons. The guidance has incorporated data from several 
experimental programs established to ensure avoidance of unintentional 
criticality in weapons programs. The experimental data has often been 
generalized by analysis of the experimental results and by theory 
benchmarked against experiments. The missions of DOE have changed 
substantially, however, and guidance for other types of activities is 
not needed. It is particularly important that guidance be developed to 
help in analyzing the safety of cleanup operations and the handling, 
storage, and shipping of miscellaneous containers that include 
fissionable material mixed with other material.
    The above problems have had a significant effect on the 
productivity of several DOE operations. They have adversely affected 
safety by extending the period of time required for meeting safety 
commitments, such as those responding to Board Recommendation 94-1. In 
so doing, they have absorbed resources potentially needed for other 
safety-related activities at DOE's defense nuclear facilities. In this 
light, the Board believes action should be taken to eliminate these 
problems and to ensure that criticality safety can continue to be 
achieved efficiently in DOE's future operations.
    Therefore the Board recommends that DOE:
    1. Restructure the program of experimental research in criticality 
established under the Implementation Plan for Recommendation 93-2 to 
emphasize determination of bounding values for criticality of systems 
most important in the current programs at DOE facilities.
    2. Organize the records of calculations and experiments conducted 
to ensure the criticality safety of DOE's past operations so as to 
provide guidance for criticality safety in similar situations in the 
future and avoid repetition of past problems.
    3. Establish a program to interpolate and extrapolate such existing 
calculations and data as a function of physical circumstances that may 
be encountered in the future, so that useful guidance and bounding 
curves will result.
    4. Collect and issue the experimental and theoretical data from the 
above in a publications as guidance for future activities.
    5. Clarify in guidance that simple, bounding methods of analysis 
can be used in place of specific theoretical analysis in setting 
criticality limits for processes, and that limits derived in this 
manner are even preferable where they serve the purpose. The decreasing 
order of preference should be experimental data, theory benchmarked 
against experimental data, and nonbenchmarked criticality analysis with 
an adequate safety margin.
    6. Develop and institute a short but intensive course of 
instruction in criticality and criticality safety at DOE's criticality 
experiments facility to serve as the foundation for a program of formal 
qualification of criticality engineers. This course should instill in 
students a familiarity with the factors contributing to criticality, 
the physical behavior of systems at and near criticality, and a 
theoretical understanding of neutron multiplication processes in 
critical and subcritical systems. A goal would be for reliance for 
criticality safety at any DOE facilities to rest in a group of 
individuals endowed with such experience.
    7. Where not already done, assign criticality safety as a staff 
function

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assisting line management, with safety responsibility residing in line 
management.
    8. Identify a core group of criticality experts experienced in the 
theoretical experimental aspects of neutron chain reactions to advise 
on the above steps and assist in resolving future technical issues.
    9. Organize funding of the criticality research and instruction 
program to improve its stability and to recognize the cross-cutting 
importance of this activity.
John T. Conway,
Chairman.
[FR Doc. 97-13977 Filed 5-28-97; 8:45 am]
BILLING CODE 3670-01-M