ML21053A039
| ML21053A039 | |
| Person / Time | |
|---|---|
| Site: | National Bureau of Standards Reactor |
| Issue date: | 10/11/2020 |
| From: | US Dept of Commerce, National Institute of Standards & Technology (NIST) |
| To: | Office of Nuclear Reactor Regulation |
| Torres P | |
| Shared Package | |
| ML21053A037 | List: |
| References | |
| Download: ML21053A039 (1) | |
Text
1 October 11, 2020
Subject:
Statement of no significant hazards resulting from license amendment request dated October 11, 2020
Reference:
NBSR Facility License TR-5, Docket 50-184 The NIST Center for Neutron Research (NCNR) is requesting an amendment to the facility license related to installation of a liquid deuterium cold source. As required by 10 CFR 50.91(a),
the following analysis is presented to show the proposed amendment does not create a significant hazard using the criteria of 10 CFR 50.92(c).
- 1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?
No, the proposed amendment would not increase the probability or consequences of an accident previously evaluated, as the proposed amendment a) does not increase the probability of an accident as the design of the proposed cold source has an identical mitigative design as the existing cold source and b) the consequences are not increased, as the total public total effective dose equivalent under the worst case accident scenario is more than a factor of four less than the analyzed maximum hypothetical accident. There is no credible accident scenario that could adversely affect the safety of the reactor.
- 2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?
No. Although NRC has published no 10 CFR50.92(c)-related guidance for test reactors to make such a determination, we are proposing to use the ICRP-66 gaseous tritium dose conversion factor to analyze the consequences of an uncontrolled release of deuterium gas. Calculations using this factor show that public doses will be well below 10 CFR 20 limits under all accident scenarios and is easily bounded by the NBSR maximum hypothetical accident calculated doses.
Such a release is thus not a different kind of accident, and poses no threat to public health and safety as stated by NRC as a criterion for a postulated accident.
- 3. Does the proposed amendment involve a significant reduction in a margin of safety?
No, the proposed amendment would not involve a significant reduction in a margin of safety. As discussed in the amendment request and above, there is no credible accident scenario that could adversely affect the safety of the reactor and the external tritium release scenario dose consequences are well below that of the NBSR maximum hypothetical accident and 10 CFR 20 limits for public doses.