Nuclear Criticality Safety Evaluations

DOE-STD-1135-99

DOE G 421.1-1, Criticality Safety Good Practices Program Guide for DOE

Non-Reactor Nuclear Facilities.

DOE G 450.4, Integrated Safety Management System Guide.

DOE/NCT-04, A Review of Criticality Accidents, March 1989.

DOE Order 420.1, FACILITY SAFETY, Section 4.3, Nuclear Criticality Safety

(supersedes DOE Order 5480.24)

DOE Order 5480.21, Unreviewed Safety Questions.

DOE Order 5480.22, Technical Safety Requirements.

DOE Order 5480.23, Nuclear Safety Analysis Reports.

DOE Order 5480.31/425.1, Start-up and Restart of Nuclear Facilities.

DOE Policy 450.4, Safety Management System Policy.

DOE-STD-3007-93 (Change Notice No. 1, September, 1998), Guidelines for

Preparing Criticality Safety Evaluations at Department of Energy Non-

Reactor Nuclear Facilities.

DOE-STD-3009-94, Preparation Guide for U.S. Department of Energy

Nonreactor Nuclear Facility Safety Analysis Reports.

DOE-STD-3011-94, Guidance for Preparation of DOE Order 5480.22 (TSR)

and DOE Order 5480.23 (SAR) Implementation Plans.

LA-10860-MS, Critical Dimensions of Systems Containing U235, Pu239, and

U233, 1986.

Reg Guide 3.71, Nuclear Criticality Safety Standards for Fuels and Material

Facilities.

TID-7016, The Nuclear Safety Guide, June 1978.

Training on these documents should be obtained by OJT combined with mentoring

from a qualified NCS Engineer. However, the various Criticality Safety Short

Courses offer sessions on review and use of these documents. See Appendix A for

recommended standards, guides and handbooks.

5.0 Nuclear Criticality Safety Evaluations

An important function of a criticality safety engineer is effective preparation of NCS

Evaluations. NCS Evaluations are performed to technically demonstrate the

subcriticality of fissionable material processes, operations, and situation for

transportation and storage under all normal and credible abnormal conditions.

Evaluators should use configuration controlled, verified, and validated software and

data sets; handbook techniques and data shown to be valid; or direct comparisons

with critical and subcritical experiment data. The NCS Engineer shall prepare

Nuclear Criticality Safety Evaluation in accordance with the guidance in DOE-STD-

3007-93.

The results from the evaluations will be categorized as passive-engineered (i.e.,

geometry), active-engineered, or administrative controls (i.e., procedures). The

preferred method of control is by passive engineered equipment design features.

When engineered methods of control are not practical, administrative control

methods may be used. When establishing NCS controls, the NCS Engineer shall