L-23-171, CFR 50.55a Request Number VR-9. Revision 0, Feedwater Check Valve Exercising Test Frequency

CFR 50.55a Request Number VR-9. Revision 0, Feedwater Check Valve Exercising Test Frequency

ML23345A086
Person / Time
Site:	Perry
Issue date:	12/08/2023
From:	Penfield R Energy Harbor Nuclear Corp
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
L-23-171
Download: ML23345A086 (1)

Text

energy Energy Harbor Nuclear Corp.

Perry Nuclear Power Plant harbor 10 Center Road Perry, Ohio 44081 Rod L. Penfield 440-280-5382 Site Vice President, Perry Nuclear December 8, 2023 L-23-171 1-0 CFR 50.55a ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Perry Nuclear Power Plant, Unit No. 1 Docket No. 50-440, License No. NPF-58 10 CFR 50.55a Request Number VR-9. Revision 0, Feedwater Check Valve Exercising Test Frequency In accordance with 10 CFR 50.55a(z)(2), Energy Harbor Nuclear Corp. hereby requests Nuclear Regulatory Commission (NRC) staff approval of request VR-9, Revision 0, that proposes an alternative valve testing frequency due to hardship or unusual difficulty without compensating increase in level of quality or safety.

The request is for use during the fourth 10-year 1ST interval, which began on May 18, 2019, and is scheduled to expire on May 17, 2029. Energy Harbor Nuclear Corp. is requesting approval of the proposed 10 CFR 50.55a request by February 1, 2025 to support scheduled outage 1R20.

The attachment identifies the affected components, the applicable code requirements, the reason for the request, and the proposed alternative and basis for use.

There are no regulatory commitments contained in this submittal. If there are any questions or if additional information is required, please contact Mr. Phil H. Lashley, Manager, Fleet Licensing, at (330) 696-7208.

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Rod L. Penfield

Perry Nuclear Power Plant L-23-171 Page 2 of 2

Attachment:

Perry Nuclear Power Plant, 10 CFR 50.SSa Request VR-9, Revision 0 cc: NRC Region Ill Administrator NRC Resident Inspector NRC Project Manager

Attachment L-23-171 10 CFR 50.55a Request VR-9, Revision 0 Page 1 of 5 Proposed Alternative in Accordance with 10 CFR 50.55a(z)(2)

--Hardship or Unusual Difficulty without Compensating Increase in Level of Quality or Safety--

1. ASME Code Component(s) Affected Component Code Valve Component Description ID Class Category Feedwater Header A 1B21-F032A 1 AC Outboard Containment Isolation Check Valve Feedwater Header B 1B21-F032B 1 AC Outboard Containment Isolation Check Valve Feedwater Header A 1N27-F559A 1 AC Inboard Containment Isolation Check Valve Feedwater Header B 1N27-F559B 1 AC Inboard Containment Isolation Check Valve Note: The feedwater check valves are Category C valves since they are self-actuating, as well as Category A valves because seat leakage is limited in the closed direction. Valves with these characteristics are designated AC in the Perry Nuclear Power Plant IST Program.

2. Applicable Code Edition and Addenda

American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants Code, 2012 Edition (OM Code).

3. Applicable Code Requirement

ASME OM Code, Subsection ISTC-3510, Exercising Test Frequency, states in part that:

Active Category A, Category B, and Category C check valves shall be exercised nominally every three months, except as provided by paragraphs ISTC-3520, ISTC-3540, ISTC-3550, ISTC-3570, ISTC-5221, and ISTC-5222.

Subsection ISTC-3522, Category C Check Valves, part (c) states that:

If exercising is not practicable during operation at power and cold shutdowns, it shall be performed during refueling outages.

Attachment L-23-171 Page 2 of 5

4. Reason for Request

The four check valves listed in Section 1 of this request are normally open piston-style check valves that allow primary feedwater to the reactor vessel and maintain reactor water level within limits during all modes of operation. During a postulated accident, the safety-related valves are designed to close, thereby isolating, and preventing a loss of reactor coolant. There are two feedwater lines with each line consisting of an outboard (1B21-F032A or 1B21F032B) and inboard (1N27-F559A or 1N27-F559B), containment isolation check valve.

The three types of tests for these check valves are exercise open, exercise close, and water leak rate. Exercise open testing is performed by verifying expected feedwater flow into the reactor vessel using control room instruments and is not a part of this request. Water leak rate testing satisfies the exercise close (EC) test requirements of the inservice testing program and can only be performed during prolonged shutdowns when other sources of reactor water level control are available and area radiation levels are reduced. As such, testing during a refueling outage is necessary in accordance with ISTC-3522(c).

Performance of the water leak rate test requires qualified leak rate contractors, as well as carpenters to erect scaffolding. Depending on the leakage results, supplemental visual inspections may be required to support testing. This test is performed via test rig by routing an air supply to each of the feedwater check valve (FWCV) inspection appendages. When air is admitted through the FWCVs, personnel can perform a visual inspection of the disc and seating surfaces using a borescope that is inserted through a drain connection on the bottom of each valve.

The total accumulated dose for all testing and maintenance activities for these evolutions is estimated at 4,000 mrem. Testing during refueling will require additional dose resulting in a hardship without a compensating increase in the level of quality and safety.

5. Proposed Alternative and Basis for Use

As an alternative to Subsection ISTC-3522(c) of the ASME OM Code, Energy Harbor Nuclear Corp. proposes to perform the water leak rate testing on a staggered basis, such that two check valves of a single feedwater line are tested each refueling outage.

By letter dated March 26, 1999 (ML021840396), the NRC staff approved Amendment 105 for the Perry Nuclear Power Plant. The amendment revised technical specification (TS) 5.5.12, Primary Containment Leakage Rate Testing Program, to state that the feedwater check valves will be tested in accordance with the Inservice Testing Program (TS 5.5.6). These valves are to be water leak rate tested to satisfy the EC test requirements of the Inservice Testing Program. The EC testing includes a water leak rate test, with an acceptance criterion of less than or

Attachment L-23-171 Page 3 of 5 equal to () 200 gallons per minute (gpm) per feedwater penetration, when tested at greater than or equal to () 1.1 Pa, where Pa is the limit for the peak containment pressure during a loss of coolant accident and is used as the method to test for proper check valve closure (Category C exercised closed) and will also ensure no significant leakage (Category A leak testing). From 2003 to present, the leakage tests performed for all four check valves have met the 200 gpm acceptance criterion.

When low pressure results are extrapolated to operating pressure levels and the valve leakage is determined to exceed the 200 gpm leakage criteria, the supplemental visual inspection via borescope evaluation is performed to check for any orifice type seat defects. The results of this testing from refueling outage 1R13 (2011) to present includes acceptable testing results during refueling outage 1R19 (2023) after having not performed the testing in refueling outage 1R18 (2021) as permitted by relief request VR-7 (Accession No. ML21031A002) and supplement (Accession No. ML21053A010). These results are provided in Table 1 and support this request for the staggered testing frequency.

The check valve visual inspection results to date have not found seating defects or missing material indicative of an orifice defect. The check valve itself is a piston-style design. For this type of check valve, the most likely failure modes are failure to open, failure to close, and restricted motion. The absence of these failure modes is validated during visual inspections and exercising the disc using air during these inspections. A failure to open or restricted motion would be self-evident during the on-line operating cycle. A failure to close has never been observed during any inspections, nor has any orifice type defect.

These check valves are expected to perform their function based on valve design, likely failure modes, historical testing results at 1.1 Pa, and visual inspections performed to date. Therefore, performing the water leak rate test on a staggered testing frequency is adequate to ensure functionality of the valves. In the event of a test failure on a feedwater check valve, the inboard and outboard check valves on the line not scheduled will be tested as an extent of condition.

6. Duration of Proposed Alternative

The proposed alternative is requested for use during the PNPP fourth 10-year in-service test interval, which began May 18, 2019, and is scheduled to end on May 17, 2029.

7. Precedent A one-time request to defer testing of these valves from the spring 2021 refueling outage to the spring 2023 refueling outage was verbally authorized by the NRC for request VR-7, Revision 0, on March 3, 2021 (ML21063A196). By letter dated May 4,

Attachment L-23-171 Page 4 of 5 2021 (ML21123A289), the NRC staff provided the safety evaluation to document the technical basis for the NRCs verbal authorization.

The proposed alternative provided in Section 5 is requested for use during the PNPP fourth 10-year in-service test interval which began May 18, 2019, and is scheduled to end on May 17, 2029. The proposed alternative would be an extension of exercise testing of the affected check valves listed in Section 1 from the spring 2023 refueling outage through the spring 2029 refueling outage. The applicable code requirements listed in Section 3 would resume during the PNPP fifth 10-year in-service test interval which is scheduled to begin May 18, 2029.

The justification for the one-time request, including the valve design, likely failure modes, historical testing results, and visual inspections, also supports performing the water leak rate test on a staggered testing frequency.

Attachment L-23-171 Page 5 of 5 Table 1 VR-9 LLRT Acceptance Criteria and Data Refueling Leakage Visual Visual Calculated Outage - Component Acceptance Inspection Inspection Leakage Date Criteria Required Result 1R13 - 2011 1B21-F0032A < 200 gpm 99.5 gpm Yes SAT 1N27-F0559A < 200 gpm 139 gpm Yes SAT 1B21-F0032B < 200 gpm 26.0 gpm Yes SAT 1N27-F0559B < 200 gpm 43.5 gpm Yes SAT 1R14 - 2013 1B21-F0032A < 200 gpm 44.03 gpm Yes SAT 1N27-F0559A < 200 gpm 100.96 gpm Yes SAT 1B21-F0032B < 200 gpm 97.76 gpm Yes SAT 1N27-F0559B < 200 gpm 36.35 gpm Yes SAT 1R15 - 2015 1B21-F0032A < 200 gpm 41.96 gpm Yes SAT 1N27-F0559A < 200 gpm 103.24 gpm Yes SAT 1B21-F0032B < 200 gpm 92.9 gpm Yes SAT 1N27-F0559B < 200 gpm 66.2 gpm Yes SAT 1R16 - 2017 1B21-F0032A < 200 gpm 14.9 gpm Yes SAT 1N27-F0559A < 200 gpm 52.48 gpm Yes SAT 1B21-F0032B < 200 gpm 189.9 gpm Yes SAT 1N27-F0559B < 200 gpm 44.8 gpm Yes SAT 1R17 - 2019 1B21-F0032A < 200 gpm 35.95 gpm Yes SAT 1N27-F0559A < 200 gpm 102.54 gpm Yes SAT 1B21-F0032B < 200 gpm 96.09 gpm Yes SAT 1N27-F0559B < 200 gpm 32.41 gpm Yes SAT 1R18 - 2021 Not performed per relief request VR-7 1R19 - 2023 1B21-F0032A < 200 gpm 49.37 gpm Yes SAT 1N27-F0559A < 200 gpm 109.93 gpm Yes SAT 1B21-F0032B < 200 gpm 131.5 gpm Yes SAT 1N27-F0559B < 200 gpm 36.57 gpm Yes SAT