RS-23-005, Response to Request for Additional Information for Quad Cities Relief Request RV-04, Inservice Testing of High Pressure Coolant Injection Drain Pot Solenoid Valves

Response to Request for Additional Information for Quad Cities Relief Request RV-04, Inservice Testing of High Pressure Coolant Injection Drain Pot Solenoid Valves

ML23017A218
Person / Time
Site:	Quad Cities
Issue date:	01/17/2023
From:	Simpson P Constellation Energy Generation
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
EPID L-2022-LLR-0070, RS-23-005
Download: ML23017A218 (1)

Text

4300 Winfield Road Warrenville, IL 60555 630 657 2000 Office January 17, 2023 10 CFR 50.55a RS-23-005 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Quad Cities Nuclear Power Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-29 and DPR-30 NRC Docket Nos. 50-254 and 50-265

Subject:

Response to Request for Additional Information for Quad Cities Relief Request RV-04, Inservice Testing of High Pressure Coolant Injection Drain Pot Solenoid Valves (EPID L-2022-LLR-0070)

References:

1. Letter from P.R. Simpson (Constellation Energy Generation, LLC) to U.S.

NRC, "Submittal of RV-04 Relief Request Associated with the Sixth Inservice Testing Interval," dated October 7, 2022 (ADAMS Accession No. ML22280A124)

2. Email from R. Kuntz (U.S. NRC) to R. Steinman (Constellation Energy Generation), "Draft Request for Additional Information - Quad Cities Alternative RV-04, Inservice Testing of High Pressure Coolant Injection Drain Pot Solenoid Valves (EPID L-2022-LLR-0070)," dated December 16, 2022 (ADAMS Accession No. ML23004A026)

In Reference 1, Constellation Energy Generation, LLC (CEG) submitted relief request RV-04 associated with the Sixth 10-Year Inservice Testing (IST) Program Interval for Quad Cities Nuclear Power Station (QCNPS). Alternative RV-04 seeks relief from American Society of Mechanical Engineers (ASME) Operation and Maintenance (OM) Code ISTC-5150 quarterly stroke timing and fail-safe requirements. The request applies to the sixth 10-Year interval which begins on February 18, 2023 and is required by 10 CFR 50.55a(f)(4) to comply with the requirements of the 2017 Edition of the Code with no Addenda.

In Reference 2, the NRC requested additional information that is needed to complete review of the proposed relief request. The attachment to this letter provides the additional information requested. There are no regulatory commitments included in this letter.

U.S. Nuclear Regulatory Commission January 17, 2023 Page 2 Should you have any questions concerning this letter, please contact Ms. Rebecca L. Steinman at 630-657-2831.

Respectfully, Patrick R. Simpson Sr. Manager Licensing Constellation Energy Generation, LLC

Attachment:

Response to Request for Additional Information for Quad Cities Alternative RV-04, Inservice Testing of High Pressure Coolant Injection Drain Pot Solenoid Valves cc: Regional Administrator - NRC Region III NRC Senior Resident Inspector - Quad Cities Nuclear Power Station

ATTACHMENT Response to Request for Additional Information for Quad Cities Alternative RV-04, Inservice Testing of High Pressure Coolant Injection Drain Pot Solenoid Valves Page 1 of 2

Background:

By a letter dated October 7, 2022 (Agencywide Documents Access and Management System (ADAMS)

Accession No. ML22280A124), Constellation (the licensee) submitted to the U.S. Nuclear Regulatory Commission (NRC) Alternative Request RV-04 regarding certain inservice testing (IST) requirements of the 2017 Edition of the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (OM Code) for the IST Program at Quad Cities Nuclear Power Station, Units 1 and 2 (Quad Cities) associated with the Sixth 10-Year IST Program interval.

Regulatory Requirements:

The NRC regulations in Section 55a, Codes and standards, in Part 50, Domestic Licensing of Production and Utilization Facilities, in Title 10, Energy, of the Code of Federal Regulations (10 CFR 50.55a) in paragraph (z), Alternatives to codes and standards requirements, state the following:

Alternatives to the requirements of paragraphs (b) through (h) of this section or portions thereof may be used when authorized by the Director, Office of Nuclear Reactor Regulation. A proposed alternative must be submitted and authorized prior to implementation. The applicant or licensee must demonstrate that:

(1) Acceptable level of quality and safety. The proposed alternative would provide an acceptable level of quality and safety; or (2) Hardship without a compensating increase in quality and safety. Compliance with the specified requirements of this section would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

Issue:

As an alternative to the ASME OM Code requirements for the high-pressure coolant injection (HPCI) drain pot solenoid valves at Quad Cities, the licensee proposes in Alternative Request RV-04 for the Sixth 10-Year IST Program interval that a functional verification test will be conducted on the drain pot level limit switches and the associated control room annunciators at least once every 2 years. In Alternative Request RV-04 for the Sixth 10-Year IST Program interval at Quad Cities, the licensee states that Alternative Request RV-04 for the Fifth 10-Year IST Program interval is the precedent for this request for the Sixth 10-Year IST Program interval. However, the Exelon letter dated February 15, 2012 (ML12046A334) describing Alternative Request RV-04 for the Fifth 10-Year IST Program interval at Quad Cities stated that a functional verification test is conducted on the drain pot level limit switches and the associated control room annunciators at least once every 92 days. The NRC staff relied on this functional verification test schedule in its safety evaluation dated February 14, 2013 (ML13042A348) in authorizing Alternative Request RV-04 for the Fifth 10-Year IST Program interval at Quad Cities.

Request:

Describe the basis for the functional verification test schedule in Alternative Request RV-04 for the Sixth 10-Year IST Program interval in comparison to the referenced precedent in Alternative Request RV-04 for the Fifth 10-Year IST Program interval at Quad Cities.

ATTACHMENT Response to Request for Additional Information for Quad Cities Alternative RV-04, Inservice Testing of High Pressure Coolant Injection Drain Pot Solenoid Valves Page 2 of 2 Constellation Response:

Quad Cities Nuclear Power Station (QCNPS) relief RV-04 for alternative testing of high pressure coolant injection (HPCI) valves 1-2301-032-SO and 2-2301-032-SO was authorized for the 5th Inservice Testing (IST) interval in ML13042A348 based on the alternative functional verification testing occurring once every 92 days (e.g., a quarterly interval). The original 6th interval RV-04 incorrectly referenced the prior the interval QCNPS RV-04 approval as precedent, when the 6th interval request extends the frequency between performance of the functional tests proposed as the alternative test to every refueling outage, or once every 2 years.

Testing valves 1(2)-2301-032 every 92 days while on-line requires a HPCI turbine trip to be initiated which renders the HPCI system unavailable and inoperable with entry into a Limiting Condition for Operation (LCO). NUREG-1482 guidance recommends weighing the safety impact of performing the test quarterly against the benefits of testing.

As stated in the 6th interval relief request, a review of the corrective action program, work history, and in-service testing history of the HPCI drain pot valves did not identify any cases where these valves failed to stroke-open since their initial addition to the IST program scope in 1994. Additionally, no defects were noted when these solenoid valves were last replaced on March 23, 2021 for Unit 1 and April 9, 2020 for Unit 2. Therefore, it is concluded that the 1(2)-2301-032 testing and maintenance history demonstrates reliable performance of this valve such that testing every 92 days does not warrant the safety impact of removing the HPCI system from service to perform the testing.

In addition to removing the HPCI system from service, performance of this test while online exposes personnel to an industrial safety hazard since the test requires connecting to and draining the drain pot level switch volume which may contain hot, pressurized steam. Performance of this test every 92 days also increases the dose received by the individuals performing the test and also requires increased contamination controls compared to the proposed 2 year frequency.

Given that these solenoid valves have had no performance issues in the last 20 years, extending the test frequency to every 2 years, would eliminate the HPCI system inoperability and unavailability vulnerability associated with testing the 1(2)-2301-032 valves, as well provide a reduction of future occupational dose accumulation. As a result, it is concluded that extending the test frequency from 92 days to 2 years for the 6th interval is justified.