ML20009C396
| ML20009C396 | |
| Person / Time | |
|---|---|
| Site: | Watts Bar  |
| Issue date: | 01/08/2020 |
| From: | Tennessee Valley Authority |
| To: | Kimberly Green Plant Licensing Branch II |
| Green K | |
| References | |
| EPID L-2020-LRM-0002 | |
| Download: ML20009C396 (14) | |
Text
Watts Bar Nuclear Plant (WBN)
Pre-Submittal Telecon for Expedited License Amendment Request to Revise Technical Specification 3.3.5, LOP DG Start Instrumentation January 8, 2020
Opening Remarks
Background
Proposed Technical Specification (TS) Change Justification for Proposed TS changes Basis for Expedited Nuclear Regulatory Commission (NRC) Review Request Schedule Milestones Closing Remarks Agenda l 2
Opening Remarks The purpose of this meeting is to discuss a proposed license amendment request (LAR) for WBN Units 1 and 2.
WBN Units 1 and 2 TS 3.3.5, Condition C, which only applies to Function 5 in Table 3.3.5-1 for the 6.9 kV Emergency Bus Undervoltage Relays, only addresses the required action when one channel per bus is inoperable (i.e.,
restore the channel to operable status within one hour). Therefore, if more than one channel per bus in Function 5 is inoperable; TVA would be required to enter TS 3.0.3 The proposed LAR will revise the WBN Units 1 and 2 TS 3.3.5, Condition C to require with one or more one channels (i.e., relays) per bus inoperable then restore the channels to operable status within one hour.
Proposed change is similar in nature to the existing Sequoyah Nuclear Plant (SQN) TS.
Proposed change will preclude an unnecessary entry into WBN Units 1 and 2 TS 3.0.3 whenever more than one unbalanced voltage relay is inoperable.
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Background===
On 8/27/19, the NRC approved a TVA fleet-wide LAR to change the TS for the TVA fleet by adding a new level of protection, Unbalanced Voltage, to the TS for the loss of power (LOP) instrumentation for the Browns Ferry Nuclear Plant (BFN),
SQN, and WBN (ML18277A110).
On 12/10/19, the NRC approved a non-voluntary LAR to correct three incorrect instrument values in WBN Units 1 and 2 TS Table 3.3.5-1, LOP DG Start Instrumentation, Function 5, 6.9 kV Emergency Bus Undervoltage (Unbalanced Voltage) (ML19336C519).
WBN Units 1 and 2 TS Table 3.3.5-1 requires three channels (i.e., relays) to be operable for Function 5.
Following implementation of the above license amendments, TVA identified that the WBN Units 1 and 2 TS 3.3.5, Condition C, which only applies to Function 5 in Table 3.3.5-1 for the 6.9 kV Emergency Bus Undervoltage relays, only addresses the required action when one channel per bus is inoperable (i.e., restore the channel to operable status within one hour). Therefore, if more than one channel per bus in Function 5 is inoperable; TVA would be required to enter TS 3.0.3.
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Proposed Technical Specification Change l 5 WBN Unit 1 TS 3.3.5 (similar change being made for Unit 2)
Proposed Technical Specification Change l 6 WBN Unit 1 TS 3.3.5 (similar change being made for Unit 2)
Justification for Proposed TS changes l 7 The failure to include an action in WBN Units 1 and 2 TS 3.3.5, Condition C for when more than one channel (i.e., relay) per bus is inoperable was an oversight on TVAs part when developing the WBN Units 1 and 2 TS 3.3.5, Condition C.
Both the current BFN and SQN TS address actions for when one or more unbalanced voltage relays are inoperable. For example, the SQN Units 1 and 2 TS 3.3.5, Condition C, states if one or more unbalanced voltage relays are inoperable, then restore the unbalanced voltage relays to operable status within one hour.
As noted in Section 2.4.3 of TVA letter CNL-18-130 (ML18324A609), which described the changes to WBN Units 1 and 2 TS 3.3.5, The one-hour completion time for the new Required Action C.1 is consistent with the completion time for Required Action B.1 (i.e., loss of function of the degraded voltage protection scheme) and is based on the low probability of an event requiring an LOP start occurring during this interval.
Required Action B.1 of WBN Units 1 and 2 TS 3.3.5 states with one or more Functions with two or more channels per bus inoperable then restore all but one channel to operable status within one hour.
Justification for Proposed TS changes l 8 Therefore, it was TVAs intent that WBN Units 1 and 2 TS 3.3.5 Condition C be consistent with Condition B by requiring similar actions if more than one channel (i.e., relay) per bus in Function 5 was inoperable [i.e., restore the inoperable channel(s) to operable status within one hour].
The proposed change to WBN Units 1 and 2 TS 3.3.5 Condition C is also consistent with the Westinghouse Standard TS (STS) (NUREG-1431, Revision 4.0), STS 3.3.5.A and B, LOP DG Start Instrumentation.
Required Action B.1 of Condition B to STS 3.3.5.A and B states with one or more Functions with two or more channels per bus inoperable then restore all but one channel to operable status within one hour. As noted in Section 3.4.4 of the NRC Safety Evaluation (SE), In addition, the NRC staff found that the proposed changes are consistent in structure and form to those developed by the staff as Standard Technical Specifications for plants of a similar design. Since the LOP relays in Table 3.3.5 perform similar functions, the NRC staff finds the proposed TS changes to be acceptable.
Justification for Proposed TS changes l 9 The proposed change to WBN Units 1 and 2 TS 3.3.5, Condition C from One or more Functions to One or more channels is editorial in nature. The Note for WBN Units 1 and 2 TS 3.3.5, Condition C states that Condition C is only applicable to Function 5 in WBN Units 1 and 2 TS Table 3.3.5-1. Therefore, WBN Units 1 and 2 TS 3.3.5, Condition C cannot apply to more than one Function as stated in the current TS wording.
The proposed change to WBN Units 1 and 2 TS Table 3.3.5-1, Function 5 to add the word Relay is also editorial in nature because the terms channel and relay are analogous for Function 5 for the unbalanced voltage relays.
Basis for Expedited NRC Review Request l 10 During the performance of maintenance on the 6.9 kilovolt (kV) Shutdown Board (SDBD) 1A-A, all three unbalanced voltage relays (i.e., 60PI1, 60PI2, and 60IP3) are removed from service.
As shown in Figure 1, the relaying for open phase conditions is monitored by the three unbalanced voltage relays on each SDBD. The maintenance activities associated with the 6.9 kV SDBD 1A-A will require the unbalanced voltage relays to be removed from service for board cleaning/inspection and will also allow restoration of the board.
The maintenance for the WBN Unit 1 6.9kV SDBD 1A-A is scheduled to be performed during the upcoming WBN Unit 1 Cycle 16 refueling outage, which is scheduled to commence on April 23, 2020.
There are no other scheduled maintenance or surveillance activities between the date of this submittal and the date for performing the maintenance on the 6.9 kV SDBD 1A-A that would render more than one unbalanced voltage relay inoperable.
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Schedule Milestones January 8, 2020 - LAR Pre-Submittal Telecon with NRC January 17, 2020 - LAR Submittal April 21, 2020 - NRC Approval of LAR (Requested)
April 23, 2020 - Implementation of LAR (Requested) l 12
Closing Remarks Proposed LAR is needed to correct an oversight in WBN Units 1 and 2 TS 3.3.5, Condition C regarding the lack of a Required Action for when more than one channel (i.e., relay) per bus is inoperable Proposed change will preclude an unnecessary entry into WBN Units 1 and 2 TS 3.0.3 whenever more than one unbalanced voltage relay is inoperable.
Proposed Change is consistent with existing WBN Units 1 and 2 TS 3.3.5, Condition B and SQN Units 1 and 2 TS 3.3.5, Condition C LAR submittal is planned for January 17, 2020 NRC approval is needed by April 21, 2020 to support maintenance on the 6.9 kV SDBD 1A-A, when all three unbalanced voltage relays are removed from service.
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