ML26027A344
| ML26027A344 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 01/27/2026 |
| From: | Ameren Missouri, Union Electric Co |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML26027A333 | List: |
| References | |
| ULNRC-06970, LDCN 25-0022, TSTF-599-A, Rev 1 | |
| Download: ML26027A344 (0) | |
Text
Enclosure to ULNRC-06970 Page 1 of 4 Evaluation of the Proposed Change DESCRIPTION AND ASSESSMENT OF THE PROPOSED CHANGE 1.
SUMMARY
DESCRIPTION Page 2 2.
DETAILED DESCRIPTION Page 2 2.1 Applicability of Safety Evaluation Page 2 2.2 Variations Page 2 3.
REGULATORY ANALYSIS Page 3 3.1 No Significant Hazards Consideration Determination Page 3 3.2 Conclusions Page 4 4.
ENVIRONMENTAL EVALUATION Page 4
Enclosure to ULNRC-06970 Page 2 of 4 DESCRIPTION AND ASSESSMENT OF THE PROPOSED CHANGE 1.0
SUMMARY
DESCRIPTION Ameren Missouri requests adoption of TSTF-599, "Eliminate Periodic Surveillance Test of Simultaneous Start of Redundant Diesel Generators," which is an approved change to the Standard Technical Specifications (STS), into the Callaway TS. The proposed change eliminates the periodic Surveillance Requirement (SR) to verify that all required diesel generators (DGs) achieve rated frequency and voltage within the specified time period when started simultaneously.
2.0 DETAILED DESCRIPTION 2.1 Applicability of Safety Evaluation Ameren Missouri has reviewed the safety evaluation for TSTF-599 provided to the Technical Specifications Task Force in a letter dated May 5, 2025. This review included the NRC staffs evaluation, as well as the information provided in TSTF-599. Ameren Missouri has concluded that the justifications presented in TSTF-599 and the safety evaluation prepared by the NRC staff are applicable to Callaway, Unit 1 and justify the requested license amendment for incorporation of the changes to the Callaway TS.
2.2 Variations The Callaway Technical Specifications contain requirements that differ from the Standard Technical Specifications (STS) (i.e., Westinghouse, NUREG-1431) on which TSTF-599 was based but are encompassed in the TSTF-599 justification. There are two variations, which are minor in nature, as follows.
- 1. Per the STS and the TS mark-ups included in TSTF-599, SR 3.8.1.20 is the last SR listed in TS 3.8.1. Thus, the mark-ups in the TSTF-599 package show this SR being removed entirely at the end of the TS 3.8.1-listed SRs (including the SR number itself). However, the Callaway Technical Specifications contain an additional SR, i.e., SR 3.8.1.21 (related to the load shedder and emergency load sequencer (LSELS) trains at Callaway) which is unaffected by TSTF-599. To eliminate SR 3.8.1.20 from the Callaway Technical Specifications, it is appropriate to reflect its elimination by deleting the SR text but keeping the SR number and inserting "Not Used." (with a period) in place of the SR text. This eliminates the need to renumber Callaway SR 3.8.1.21, thus keeping SR 3.8.1.21 in its place and preserving the existing SR numbering/order.
- 2. The TS mark-ups in the TSTF-599 package include a mark-up of SR 3.8.2.1, which is applicable during shutdown conditions (Modes 5 and 6). This SR specifies what SRs under TS 3.8.1 (which is applicable in Modes 1, 2, 3 and 4) are applicable to SR 3.8.2.1, except for certain SRs (that are specifically identified as exceptions, i.e., as not applicable). Since SR 3.8.1.20 is included in the list of excepted SRs, the TSTF-599 mark-up to SR 3.8.2.1 includes deleting "SR 3.8.1.20" based on its elimination from TS 3.8.1. For Callaway, however, SR 3.8.1.20 is not referred to at all in
Enclosure to ULNRC-06970 Page 3 of 4 SR 3.8.2.1. Consequently, the TS mark-ups for Callaway do not include the change proposed for SR 3.8.2.1 per TSTF-599 (since the change is not applicable or needed).
As noted above, these variations do not change the effect or purpose of TSTF-599 as it applies to the Callaway Technical Specifications. The removal of SR 3.8.1.20 is still being proposed consistent with and as justified by TSTF-599.
3.0 REGULATORY ANALYSIS
3.1 No Significant Hazards Consideration Determination Ameren Missouri requests adoption of TSTF-599, "Eliminate Periodic Surveillance Test of Simultaneous Start of Redundant Diesel Generators," which is an approved change to the Standard Technical Specifications (STS), into the Callaway, Unit 1 TS. The proposed change eliminates the periodic Surveillance Requirement (SR) to verify that all required diesel generators (DGs) achieve rated frequency and voltage within the specified time period when started simultaneously.
Ameren Missouri has evaluated if a significant hazards consideration is involved with the proposed amendment by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:
1.
Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No The proposed change eliminates a periodic Surveillance test which verifies that all required diesel generators (DGs) achieve rated frequency and voltage within the specified time period when started simultaneously. Simultaneous start of the redundant DGs is not an initiator of any accident previously evaluated. The fast start of the DGs is verified by other Surveillance tests, and historical performance of the simultaneous test has always been successful. As a result, the DG reliability and the attendant effect on the consequences of any accident previously evaluated are not affected.
Therefore, the proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
2.
Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated?
Response: No The proposed change eliminates a periodic Surveillance test which verifies that all required diesel generators (DGs) achieve rated frequency and voltage within the specified time period when started simultaneously. No new or different accidents result from the proposed change.
Enclosure to ULNRC-06970 Page 4 of 4 The changes do not involve a physical alteration of the plant (i.e., no new or different type of equipment will be installed) or a change in the methods governing normal plant operation. In addition, the changes do not impose any new or different requirements. The changes do not alter assumptions made in the safety analysis. The proposed changes are consistent with the safety analysis assumptions and current plant operating practice.
Therefore, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
3.
Does the proposed amendment involve a significant reduction in a margin of safety?
Response: No The proposed change eliminates a periodic Surveillance test which verifies that all required diesel generators (DGs) achieve rated frequency and voltage within the specified time period when started simultaneously. The proposed change does not adversely affect existing plant safety margins or the reliability of the equipment assumed to operate in the safety analysis. As such, there are no changes being made to safety analysis assumptions, safety limits or limiting safety system settings that would adversely affect plant safety because of the proposed change.
Therefore, the proposed change does not involve a significant reduction in a margin of safety.
Based on the above, Ameren Missouri concludes that the proposed change presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of no significant hazards consideration is justified.
3.2 Conclusions Based on the considerations discussed above, 1) there is a reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, 2) such activities will be conducted in compliance with the Commission's regulations, and 3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
4.0 ENVIRONMENTAL EVALUATION The proposed change would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or a significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed change.