|Person / Time|
|From:||Schaaf R G|
Tennessee Valley Authority
Division of Operating Reactor Licensing
|Schaaf R G|
|Download: ML17340B063 (13)|
Watts Bar Nuclear Plant Pre-Submittal Teleconference for Proposed License Amendment Request Regarding Technical Specification 3.6.3, "Containment Isolation Valves," Surveillance Requirement 126.96.36.199 December 7, 2017
Agenda *Opening Remarks and Purpose of the Proposed License Amendment Request (LAR)
- Proposed Surveillance Requirement (SR) 188.8.131.52 Changes
- Technical Analysis of the Proposed LAR
- Regulatory Precedent
- Schedule for Submittal
- Summary and Closing Remarks
l 2 Opening Remarks and Purpose of the Proposed LAR
- The proposed Technical Specification (TS) amendment revises the Watts Bar Nuclear Plant (WBN) Units 1 and 2 TS 3.6.3, "Containment Isolation Valves," SR 184.108.40.206 and associated Bases to change the frequency to "In accordance with the Containment Leakage Rate Testing Program
." *The WBN Containment Leakage Rate Testing (CLRT) Program is described in TS 220.127.116.11, "Containment Leakage Rate Testing Program," and implemented in accordance with 10 CFR Part 50, Appendix J, Option B, and Regulatory Guide (RG) 1.163, "Performance-Based Containment Leak
- RG 1.163 allows a nominal test interval of 30 months for containment purge and vent valves.
- Each WBN Unit 1 and 2 Containment Purge System contains ten containment penetrations (i.e., X
-4, X-5, X-6, X-7, X-9A, X-9B, X-10A, X-10B, X-11, and X-80). *Each penetration contains redundant containment isolation valves (total of 20 valves per unit).
- The valves are pneumatically-operated POSI-SEAL butterfly valves with resilient seals.
- During normal plant operations, these valves are normally closed except containment penetration X
-80 (containment vent penetration), which is normally open. l 7 Technical Analysis of the Proposed LAR
l 8 *Table 1 of the LAR provides a table of the last ten years of as-found leak rate history of the WBN Unit 1 Containment Purge System valves. *Table 2 of the LAR provides a similar table for the WBN Unit 2 Containment Purge System valves. -Two years of as
-found leak rate history is provided due to the limited operating experience of WBN Unit 2. -The long term leakage performance of the WBN Unit 2 valves is expected to be similar to their WBN Unit 1 counterparts, because the valves are the same design including manufacturer and model number.
Technical Analysis of the Proposed LAR
l 9 *The administrative limit for the Containment Purge System valve leakage rate is 12.32 standard cubic feet per hour (scfh). *Since the initial startup for Unit 1 (1996) and Unit 2 (2016), the administrative limit has never been exceeded. *The largest leakage rate over the past ten years for Unit 1 was 3.18 scfh for penetration X
-7 on 10/17/2008. *The largest leak rate for Unit 2 was 8.84 scfh for penetration X
-10A on 8/8/2016.
- The as-found leak rate history of these valves supports extending the test interval beyond the current frequency of 184 days and within 92 days of any opening, to the NRC Regulatory Guide 1.163 recommended frequency of once every 30 months.
- The proposed TS change is similar to those approved by NRC for the following nuclear power plants that also revised their SR frequency for the containment purge valves to be in accordance with the Containment Leakage Rate Testing Program:
-McGuire Nuclear Station, Units 1and 2 (ML022540102)
- 12/7/17 - Pre-submittal teleconference with NRC
- 1/31/18 - Submit LAR to NRC
- Request NRC approval by 1/31/19 with a 30
-day implementation dat e *March 2018 - Telecon or meeting to discuss any NRC questions (if needed)
l 11 Closing Remarks
- Proposed LAR reflects the operating experience of the WBN Containment Purge System valves. *Proposed LAR w ill result in decreased radiological exposure to personnel and reduces the safety risk associated with performing this SR in the WBN Unit1 and Unit 2 Annulus. *Proposed LAR is consistent with industry precedence.