ML23102A175
| ML23102A175 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 04/14/2023 |
| From: | Ballard B Nuclear Management Co, Xcel Energy |
| To: | Domingos C Division of Operating Reactor Licensing |
| Kuntz R | |
| References | |
| Download: ML23102A175 (1) | |
Text
Prairie Island License Amendment Request to Revise TS 3.7.8, Cooling Water (CL) System Required Actions 04.14.2023
Agenda Purpose
Background
Proposed Licensing Action Schedule
© 2022 Xcel Energy 2
Purpose
© 2022 Xcel Energy The purpose of this meeting is to discuss proposed license amendment for Prairie Island Nuclear Generating Plant (PINGP) Units 1 and 2 TS 3.7.8, which:
Revises the Required Actions of TS 3.7.8, Cooling Water (CL) System, Condition B, to reduce from two to one the required number of safeguard CL pumps to be verified operable for the operable header when one CL header is inoperable.
Deletes from TS 3.7.8, Condition B, a footnote from the one-time change of Amendments 237/225.
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=
Background===
© 2022 Xcel Energy The Prairie Island CL system design includes:
Two redundant headers in independent trains, Two diesel driven cooling water pumps (12 and 22, one dedicated to each train),
One safety related motor driven cooling water pump (121) that is backed by Unit 2 emergency diesel generators and can be aligned in safeguards mode to either train, and Two non-safety related motor driven pumps (11 and 21) for normal operation.
In the event of a safeguards actuation, the normal ring header configuration automatically splits into two trains.
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5 Background (continued) 5
Background (continued)
© 2022 Xcel Energy A single CL pump can provide sufficient cooling for both:
one unit during the injection and recirculation phases of a postulated loss of coolant accident maintaining a second unit in a safe shutdown condition.
Sufficient cooling is provided by either:
the diesel driven cooling water pump (DDCLP) associated with the operable CL header or the safeguards motor driven cooling water pump (121 MDCLP) aligned for safeguards on the operable CL header 6
Proposed Licensing Action
© 2022 Xcel Energy Current PINGP TS 3.7.8, Condition B, requires more equipment to be operable than needed for a CL train to meet its safety function.
This could lead to a potential dual unit shutdown when a single CL pump on the operable CL header would meet the CL safety function.
NSPM proposes to revise the Required Actions of TS 3.7.8, Condition B, to verify that either:
the DDCLP on the operable CL header is operable or the 121 MDCLP is operable (in support of the operable CL header) 7
Proposed Licensing Action (continued)
© 2022 Xcel Energy NSPM also proposes to remove the footnote from TS 3.7.8 for the one-time change to Completion Time implemented with Unit 1 and Unit 2 Amendments 237 and 225, respectively.
The TS 3.7.8 Bases will be revised accordingly.
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Proposed Licensing Action (continued)
© 2022 Xcel Energy The LAR will be not be risk-informed, but NSPM will include risk insights with the LAR The equipment associated with the operable CL train increases in importance due to loss of redundancy.
Risk is managed under the Maintenance Rule (a)(4) program prior to exceeding the front stop of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for TS 3.7.8, Condition B.
After exceeding the front stop, the risk is managed using both the Maintenance Rule (a)(4) and Risk-Informed Completion Time programs.
Both programs evaluate the increase in risk and implement risk management actions.
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Proposed Licensing Action (continued)
Summary of Proposed Technical Specifications Changes
© 2022 Xcel Energy 10
Proposed Licensing Action (continued)
Summary of Proposed Technical Specifications Changes
© 2022 Xcel Energy 11
Schedule
© 2022 Xcel Energy
- NSPM plans to submit the LAR in May 2023 and request NRC approval 12 months from acceptance with implementation within 90 days of approval.
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