ML20302A123
| ML20302A123 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 10/28/2020 |
| From: | Kimberly Green Plant Licensing Branch II |
| To: | Jim Barstow Tennessee Valley Authority |
| Green K, NRR/DORL/LPL2-2, 415-1627 | |
| References | |
| EPIDS L-2020-LRM-0090 | |
| Download: ML20302A123 (11) | |
Text
Watts Bar Nuclear Plant (WBN)
Non-Voluntary Application to Modify WBN Unit 1 and Unit 2 Technical Specification (TS) Surveillance Requirement (SR) 3.6.15.4, Shield Building" October 28, 2020
Agenda l 2 Opening Remarks
Background
Proposed Technical Specification (TS) Changes Basis for Proposed TS Changes Regulatory Precedent Schedule Milestones Closing Remarks
Opening Remarks The proposed non-voluntary license amendment request (LAR) revises WBN Unit 1 and 2 SR 3.6.15.4 to:
Resolve a non-conservatism regarding the potential to allow more shield building inleakage than analyzed in the safety analysis Align SR 3.6.15.4 with Revision 4 to the Westinghouse Standard TS (STS) (NUREG-1431)
Currently plant operations are administratively controlled as described in AL 98-10. In accordance with the guidance in AL 98-10, this LAR is required to resolve a non-conservative TS and is not a voluntary request from a licensee to change its licensing basis.
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Background===
Current SR 3.6.15.4 was initially based on EGTS (SR 3.6.5.5) when TVA issued the proposed TS for WBN Unit 1 based on the Restructured Standard Technical Specifications (RSTS) (ML073520334 and ML073610028)
Demonstrate each EGTS train produces a pressure equal to or more negative than [-0.5] inches water gauge in the annulus relative to the Mechanical Equipment Room El. 772 within [ ] minute after a start signal with an inleakage of
< [500] cfm.
Subsequently, on August 27, 1992, TVA revised and updated the draft TS to be in accordance with the latest draft of NUREG-1431, Revision 0. EGTS SR 3.6.5.5 was renumbered as SR 3.6.9.4 (ML073600872 and ML073200281)
Verify each EGTS train produces an annulus pressure equal to or more negative than -0.5 inch water gauge with respect to the El. 772 mechanical equipment-room with an inleakage of < 250 cfm at a system flow of 4000 + 10% cfm.
September 1992, NUREG-1431, Revision 0, published. New STS 3.6.19, Shield Building (Dual and Ice Condenser), SR 3.6.19.4 states:
Verify each Shield Building Air Cleanup System train with final flow ~ [ ] cfm produces a pressure equal to or more negative than [-0.5] inch water gauge in the annulus within [22] seconds after a start signal.
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Background (continued)
On April 2, 1993 (ML073230276), the NRC transmitted the proof and review version of the WBN Unit 1 TS for TVAs review and comment.
SR 3.6.9.4 for the EGTS revised as follows: Verify each EGTS train flow rate is 3600 and < 4400 cfm.
SR 3.6.15.4 created Verify each Emergency Gas Treatment System train with final flow > 3600 and < 4400 cfm produces an annulus pressure equal to or more negative than -0.5 inch water gauge with respect to EL. 772 mechanical equipment room and with an inleakage of < 250 cfm within [TDB] seconds after a start signal.
WBN Unit 1 operating license (OL) was issued on February 7, 1996 (ML073460319 and ML080290360). Time requirement in SR 3.6.15.4 moved to SR 3.6.9.4 as follows:
SR 3.6.9.4 for the EGTS revised as follows: Verify each EGTS train flow rate is 3600 and < 4400 cfm within 20 seconds from the initiation of a Containment Isolation Phase A signal.
SR 3.6.15.4 revised to state Verify each Emergency Gas Treatment System train with final flow > 3600 and < 4400 cfm produces an annulus pressure equal to or more negative than -0.61 inch water gauge at elevation 783 with respect to the atmosphere and with an inleakage of < 250 cfm.
This is the current verbiage for SRs 3.6.9.4 and 3.6.15.4 The WBN Unit 2 OL was issued on October 22, 2015 (ML15251A587) and mirrored the WBN Unit 1 TS l 5
l 6 Proposed Change to WBN Unit 1 and 2 SR 3.6.15.4, Shield Building Current WBN Unit 1 and 2 SR 3.6.15.4, Shield Building STS SR 3.6.8.4, Shield Building (Dual and Ice Condenser)
SR 3.6.8.4 Verify the shield building can be maintained at a pressure equal to or more negative than [-0.5] inch water gauge in the annulus by one Shield Building Air Cleanup System train with final flow [ ] cfm within [22] seconds after a start signal.
[ [18] months on a STAGGERED TEST BASIS for each Shield Building Air Cleanup System Train OR In accordance with the Surveillance Frequency Control Program ]
SR 3.6.15.4 Verify each Emergency Gas Treatment System train with final flow 3600 and 4400 cfm produces an annulus pressure equal to or more negative than -0.61 inch water gauge at elevation 783 with respect to the atmosphere and with an inleakage of 250 cfm.
In accordance with the Surveillance Frequency Control Program SR 3.6.15.4 Verify the Shield Building can be maintained at each Emergency Gas Treatment System train with final flow 3600 and 4400 cfm produces an annulus pressure equal to or more negative than -0.63 inch water gauge at elevation 783 with respect to the atmosphere and with an inleakage of 250 cfm by one Emergency Gas Treatment System train with final flow 3600 and 4400 cfm within 20 seconds from the initiation after a start signal. (highlighted text is consistent with the current time requirement in SR 3.6.9.4 for the EGTS)
In accordance with the Surveillance Frequency Control Program
Basis for Proposed Change to SR 3.6.15.4 Aligns SR 3.6.15.4 with the STS 3.6.8.4 Change from -0.61 inch water gauge (in. w.g.) to -0.63 in. w.g Error discovered in calculation of this value As noted in TVA letter CNL-19-077, Application to Modify Watts Bar Nuclear Plant (WBN) Unit 1 and Unit 2 Technical Specifications 3.6.15, Shield Building, (WBN-TS-19-10) (ML19340B773), a calculated value of -0.63 inch w.g. at the elevation of the pressure sensors ensures the pressure at any elevation in the annulus is equal to or more negative than -0.25 inch w.g. consistent with BTP 6-3 Removal of inleakage value of 250 cfm Aligns SR 3.6.15.4 with the STS 3.6.8.4 This parameter is not included in any Surveillance Requirement in the STS Retain in current plant procedures The time requirement of 20 seconds ensures that the Shield Building can be rapidly drawn down to a negative pressure at all elevations in the Shield Building and ensures that no significant quantity of radioactive material leaks from the Shield Building prior to developing the negative pressure.
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Regulatory Precedent The proposed changes are consistent with the Westinghouse STS in NUREG-1431, Revision 4 There are no other applicable regulatory precedents regarding the changes proposed in this LAR l 8
Planned Schedule Milestones November 2020 - LAR Pre-Submittal Meeting with NRC January 2021 - LAR Submittal - Request NRC Approval within 12 Months of Submittal l 9
Closing Remarks l 10