ML22024A042
| ML22024A042 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 01/19/2022 |
| From: | Angela Wu NRC/NRR/DNRL/NLRP |
| To: | |
| Wu A, 301-415-2995 | |
| Shared Package | |
| ML22024A002 | List:
|
| References | |
| Download: ML22024A042 (3) | |
Text
Oconee Nuclear Station (ONS) SLRA: Breakout Questions SLRA TLAA Section: Section 4.1, Identification of Time-Limited Aging Analyses TRP: 141
Question SLRA SLRA Background / Issue Discussion Question / Request Number Section(s), Page (As applicable/needed)
Table(s)
A. Discussion Topics or Questions for SLRA TLAA Identification Methodology and Results -
Main Audit Portal Reference Document: ONS Calculation No. OSC-2077-03-SLR-0500, Revision 1 A.1 4.1.1, 4 No questions at this time on those analyses No Questions at this time. Bases for all analyses evaluated in 4,1,2 4-10 identified as TLAAs in the SLRA versus those the ONS calculation as meeting or not meeting the definition of analyses that were identified either in the a TLAA in 10 CFR 54.3(a) are well explained, along with the Tables SLRA or the ONS calculation as not meeting criterion not met if the analysis is 4.1.4-1, one or more of the six criteria for TLAAs not a TLAA.
4.1.4-2, in 10 CFR 54.3(a).
and 4.1.4-3 For the SLRA, the staff confirmed the UFSAR bases for the HELB assessment do not involve time-dependent parameters defined by the current operating term (i.e., the ONS HELB basis in the CLB is different from that approved by the staff for many other NRC-licensed US PWRs)
B. Discussion Topics or Questions for Regulatory Exemption Identification Methodology and Results -
Main Audit Portal Reference Document: ONS Calculation No. OSC-2077-03-SLR-0500, Revision 1 B.1 4.1.3 4-3 Topics and Regulatory Exemptions of In SLRA Section 4.2.4 and in SLRA Tables 4.1.4-1 and 4.1.4-2, Reference. the applicant clearly identifies that the P-T limits calculated in accordance with the methods in 10 CFR Part 50, Appendix G a) 10 CFR 50.60(b) Exemption Requested are TLAAs for the ONS SLRA. In the staffs March 1999 safety October 15, 1998 (ADAMS ML15112A279) evaluation approving the exemption, the staff granted the and Approved on March 29, 1999 (ADAMS exemption in accordance with ML012050426) Under the Requirements of 10 CFR 50.12 and stated that the calculation of the LTOP 10 CFR 50.12 - Exemption Request for use of system pressure lift setpoint is based on the specified P-T limit ASME Code Cases N-514. curve (it is in reference to the plant P-T limit cooldown curve) at a level less than or equal to 110 percent of the pressure limit set b) 10 CFR 50.60(b) Exemption Requested in the P-T curve (i.e., for the temperature associated with the May 11, 1999 and Approved on July 29, 1999 arming temperature for the LTOP system in the P-T limit (ADAMS ML012050097) Under the cooldown curve).
Requirements of 10 CFR 50.12 - Exemption Request for use of ASME Code Cases N-514, In regard to the Exemption of July 29, 1999 (for the request of N-588, and Draft N-626 (currently N-640). May 11, 1999), which granted approval for the use of Code Cases N-588 and Draft N-626 (N-640), the staff agrees that the In the Table located on Page 11 of Appendix exemptions are not based on a TLAA. The staff also confirmed B of the referenced ONS calculations, the that, in the safety evaluation for the exemption request of May applicant evaluates whether the regulatory 11, 1999, the staff indicated that the exemption for use of Code exemption of March 29, 1999 for using ASME Case N-514 was not necessary because the definition of the Code Case N-514 (i.e., for LTOP system enable temperature as RTNDT = 90 ºF is found only in an NRC pressure lift and system arming temperature Branch Technical Position.
setpoints) is a 10 CFR 50.12-granted exemption that remains in effect and is based Thus, the staff has noted that two entirely different bases in on a TLAA. The applicant clearly states in the regard to whether an exemption for use of Code Case N-514 table that the exemption allowing use of Code exists in the CLBs for ONS Units 1, 2, and 3. The applicant Case N-514 for calculation of the LTOP should be prepared to discuss whether the Regulatory system setpoints is based on the results of the Exemption for use of ASME Code Case N-514 is still part of the P-T limits that are established and calculated CLB record (i.e., remains in effect), and if so, whether the in accordance with the methodologies for P-T exemption is based on a TLAA.
limit calculations in 10 CFR part 50, Appendix G. The applicant then states that the granted regulatory exemption for Code Case N-514 is not based on the results of a TLAA.
In the Table located on Page 12 of Appendix B of the referenced ONS calculations, the applicant evaluates whether the regulatory exemption of July 29, 1999 for using ASME Code Cases N-514 (a second request for using the code case), N-588, or Draft N-626 (now N-640) are based on TLAAs and remains in effect. On page 12 of the ONS calculation, the applicant quotes the following statement in the safety evaluation regarding the need for an exemption of Code Case N514: Since the prior definition of the enable temperature as RTNDT = 90 ºF is found only in an NRC Branch Technical Position, an exemption is not required.