Document: NUREG-0800
Document ID: 723c7d66-7b0b-443a-af9b-ec3026461a0c
Document Type: srp
Title: - 12.4
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1130/ML113081427.pdf
Revision Date: 2023-06
Chapter: 12
Section ID: 12.3
CFR Part: 
CFR Title: 

Content:
.2 of NUREG-0737. The analysis should consider access to, stay time in, and egress from these vital areas. 2. Shielding The staff will evaluate the shielding design in terms of the assumptions used to calculate shield thickness, the calculational methods used, and the parameters chosen. A number of acceptable shielding calculational codes are available that are effective for determining the necessary shield thickness for gamma ray and combination neutron-gamma sources. The code description file of the Radiation Safety Information Computational Center (formerly the Radiation Shielding Information Center) at Oak Ridge National Laboratory includes most of the codes used by shield designers, which means that the codes have been tested and authenticated for operation, but not for reliability and accuracy. Radiation shielding codes vary in complexity and accuracy from the relatively simple point-kernel methods, to the more complex discrete ordinates methods, to the still more rigorous Monte Carlo methods. The staff may use these codes, as necessary, to calculate dose rates for given shield designs and source strengths as a confirmation of the applicant’s method. The applicant’s shielding design is acceptable if the methods are comparable to commonly accepted shielding calculations and if assumptions regarding source terms, cross sections, shield and source geometries, and transport methods are realistic. Labyrinth shielded access ways and penetrations should be used to minimize radiation steaming and scatter around shields. Composition of the shielding material should be selected to minimize, to the extent practicable, the potential for the shield itself to become a radiation source (either from activation of the shield material or production of secondary radiation resulting from interactions with the primary radiation). Effective shield design is essential to meeting the criterion that ORE will be ALARA. In addition, RG 1.69 and ANSI/ANS-6.4-1997 provide guidance on