ML24080A502
| ML24080A502 | |
| Person / Time | |
|---|---|
| Site: | Susquehanna  |
| Issue date: | 03/27/2024 |
| From: | Hipolito Gonzalez Plant Licensing Branch 1 |
| To: | Casulli E Susquehanna |
| Klett A | |
| References | |
| EPID L-2023-LLR-0043 | |
| Download: ML24080A502 (6) | |
Text
March 27, 2024
SUSQUEHANNA STEAM ELECTRIC STATION, UNITS 1 AND 2 - AUTHORIZATION AND SAFETY EVALUATION FOR ALTERNATIVE REQUEST RR01 FOR FIFTH 10-YEAR INSERVICE TESTING PROGRAM (EPID L-2023-LLR-0043)
LICENSEE INFORMATION
Recipients Name and Address: Edward Casulli Site Vice President Susquehanna Nuclear, LLC 769 Salem Boulevard NUCSB3 Berwick, PA 18603 -0467
Licensee: Susquehanna Nuclear, LLC
Plant Name and Units: Susquehanna Steam Electric Station (Susquehanna),
Units 1 and 2
Docket Nos.: 50-387 and 50-388
APPLICATION INFORMATION
Submittal Date: August 3, 2023
Submittal Agencywide Documents Access and Management System (ADAMS) Accession No.: ML23215A173 (Enclosure 1, Relief Request RR01) 1
Supplement Date: January 4, 2024
Supplement ADAMS Accession No.: ML24004A146
Applicable Inservice Testing (IST) Program Interval and Interval Start/End Dates:
Fifth 10-Year IST Program interval (June 1, 2024, to May 31, 2034)
Alternative Provision: The licensee requested an alternative under Title 10 of the Code of Federal Regulations (10 CFR), Section 50.55a, paragraph (z)(1).
IST Requirements:
Edition 2020 of the American Society of Mechanical Engineers (ASME) Operation and Maintenance of Nuclear Power Plants, Division 1, OM Code: Section IST (ASME OM Code),2 Subsection ISTC, Inservice Testing of Valves in Water-Cooled Reactor Nuclear
1 Relief Request RR01, as supplemented, is referred to as Alternative Request RR01 in this safety evaluation to denote that it is a proposed alternative.
2 All references to ASME OM Code in this document are to Edition 2020 unless another edition is explicitly cited.
Power Plants, paragraph ISTC-3522, Category C Check Valves, subparagraph (c),
states, If exercising is not practicable during operation at power and cold shutdown outages, it shall be performed during refueling outages.
ASME OM Code, Subsection ISTC, paragraph ISTC-3700, Position Verification Testing, states, in part, Valves with remote position indicators shall be observed locally at least once every 2 yr [years] to verify that valve operation is accurately indicated.
10 CFR 50.55a(b)(3)(xi), OM condition: Valve Position Indication, states, in part:
When implementing paragraph ISTC-3700, Position Verification Testing, in the ASME OM Code, 2012 Edition through the latest edition of the ASME OM Code incorporated by reference in paragraph (a)(1)(iv) of this section, licensees must verify that valve operation is accurately indicated by supplementing valve position indicating lights with other indications, such as flow meters or other suitable instrumentation to provide assurance of proper obturator position for valves with remote position indication within the scope of Subsection ISTC including its mandatory appendices and their verification methods and frequencies.
Applicable Code Edition and Addenda: ASME OM Code, 2020 Edition, as incorporated by reference in 10 CFR 50.55a
Applicable Code Components Affected:
ASME OM Code components applicable to Alternative Request RR01 are the excess flow check valves (EFCVs) for various systems as listed in section 1 of enclosure 1 of the submittal.
Brief Description of the Proposed Alternative:
The licensee stated that it is presently testing the subject EFCVs on a refueling outage frequency as required by the ASME OM Code, as incorporated by reference in 10 CFR 50.55a.
As an alternative to testing the subject EFCVs during a single refueling outage per ASME OM Code and 10 CFR 50.55a(b)(3)(xi) testing frequency requirements, the licensee proposed to test the EFCVs on a representative sampling basis of approximately 20 percent every refueling outage with verification of remote position indication, and that each EFCV will be tested at least once within a 10-year interval. The licensees basis for this alternative is that testing a sample of EFCVs each refueling outage provides a level of safety and quality equivalent to that of the ASME OM Code-required testing.
The documents located at the ADAMS Accession Nos. identified above have additional details about the licensees request.
STAFF EVALUATION
ASME OM Code, Subsection ISTC, paragraph ISTC -3510, Exercising Test Frequency, requires, in part, that active check valves shall be exercised nominally every 3 months.
ASME OM Code, Subsection ISTC, paragraph ISTC -3522(a), requires that during operation at power, each check valve shall be exercised or examined in a manner that verifies obturator travel by using the methods in paragraph ISTC -5221. ASME OM Code, Subsection ISTC, paragraph ISTC -3522(c), requires that if exercising is not practicable during operation at power and cold shutdown outages, exercising of the valve shall be performed during refueling outages. ASME OM Code, Subsection ISTC,
paragraph ISTC-3700, requires that valves with remote position indicators shall be observed locally at least once every 2 years to verify t hat valve operation is accurately indicated. The U.S. Nuclear Regulatory Commission (NRC) regulations in 10 CFR 50.55a(b)(3)(xi) require that licensees implementing the 2012 Edition and more recent editions of the ASME OM Code supplement the requirements in paragraph ISTC -3700 to verify that the remote position indication for the applicable valves provides proper obturator position.
In Alternative Request RR01, the licensee stated that EFCVs are provided in each instrument process line that penetrates primary containment in accordance with NRC Regulatory Guide 1.11, Instrument Lines Penetrating the Primary Reactor Containment (ML100250396).
The EFCVs are designed to close upon rupture of the instrument line downstream of the EFCV, and to otherwise remain open. The licensee stated that the EFCVs listed in section 1 of the submittal cannot be exercised during plant operation because closing these valves would isolate instrumentation required for power operation. As an alternative to ASME OM Code, Subsection ISTC, paragraphs ISTC -3510, ISTC-3522, and ISTC-3700, as supplemented by 10 CFR 50.55a(b)(3)(xi), the licensee proposed that the subject EFCVs be tested on a representative sampling basis of approximately 20 percent every refueling outage with remote position indication verification and that all EFCVs be tested at least once within a 10 -year interval.
The licensees justification for Alternative Request RR01 is based on GE Nuclear Energy NEDO-32977-A, Excess Flow Check Valve Testing Relaxation, dated June 2000 (ML003729011). The topical report provided: (1) an estimate of the frequency of a steam release into the reactor building from a break in an instrument line concurrent with an EFCV failure to close, and (2) an assessment of the radiological consequences of such a release.
The NRC staff reviewed NEDO-32977-A and issued a safety evaluation on March 14, 2000 (ML003691722). In its evaluation, the NRC staff found that the test interval could be extended up to a maximum of 10 years. In conj unction with this finding, the NRC staff noted that each licensee that adopts the relaxed test interval program per NEDO-32977 -A for EFCVs must have a failure feedback mechanism and a corrective action program (CAP) to ensure EFCV performance continues to be bounded by the topical report results. Also, per NEDO-32977-A and NRCs safety evaluation for the report, each licensee crediting the topical report to relax the EFCV testing interval must perform a plant -specific radiological dose assessment, EFCV failure analysis, and release frequency analysis to confirm that they are bounded by the generic analyses of the topical report. In its supplement, the licensee described its actions to address the conditions specified in NEDO -32977-A related to EFCV failure rate and release frequency, failure feedback mechanism and CAP, and radiological dose assessment. Based on its re view, the NRC staff finds the licensees response to be acceptable related to the applicability of NEDO -32977-A and conformance with the topical report and NRCs associat ed safety evaluation conditions regarding radiological dose assessment, EFCV failure rate, release frequency, and the proposed failure feedback mechanism and CAP.
The NRC staff reviewed the licensees description of the design of the EFCVs in Alternative Request RR01. In an EFCV, a spring holds the poppet open under static conditions such that the valve will close upon sufficient differential pressure across the poppet. Functional testing of the valve is accomplished by venting the instrument side of the EFCV. The resultant increase in flow imposes a differential pressure across the poppet, which compresses the spring and decreases flow through the valve. Based on its review, the NRC staff finds that these EFCVs are not designed with a stem-to-disk connection that is susceptible to separation.
The NRC staff reviewed the licensees description in Alternative Request RR01 of its plans to verify the remote position indication for the EFCVs. The licensee stated the remote position indication would be verified in the closed direction on a representative sampling basis to coincide with the associated exercise test. After the close position test, the valve would be reset, and the remote open position indication will be verified. The licensee stated that obturator verification for EFCVs equates to the position of the poppet assembly, which is verified by secession of flow during testing, and detected by a change to the status of indicating lights. The licensee stated that the current methodology used for functional testing of the EFCVs would be credited to meet the obturator verification requirements on the representative sampling basis.
The licensee indicated that control room operators monitor the EFCV indicating lights. The licensee stated that any EFCV test failures and EFCVs with abnormal position indication displays will be entered into the CAP. The NRC staff finds that the remote position verification alternative supports an extension of the ISTC -3700 test interval as supplemented by 10 CFR 50.55a(b)(3)(xi).
The licensee stated that its test experience with the EFCVs is consistent with the reliable performance history documented in NEDO -32977-A and that the EFCVs have been highly reliable with very infrequent failures. The licensee stated that the field test procedure and IST program plan would be revised to assure that each EFCV failure is entered into the CAP and evaluated against performance criteria with corrective actions taken based on the failure analysis and trend in failures. In it supplement, the licensee stated that if failures exceed the performance criteria of less than or equal to one failure during a 24 -month rolling average, then the IST program plan would require a cause evaluation and determination of additional testing requirements. The licensee stated that any failed valves would be tested during the next refueling outage.
The licensee stated that the subject EFCVs are containment isolation valves, but are classified as ASME OM Code, Category C valves. The licensee stated that these EFCVs are excluded from Type C testing per 10 CFR Part 50, Appendix J, Primary Reactor Containment Leakage Testing for Water-Cooled Power Reactors, because of the size of the instrument lines or upstream orifices and, therefore, the subject EFCVs have no safety -related seat leakage criteria.
Based on its review, the NRC staff finds that the licensee has supported the proposed testing and schedule in Alternative Request RR01 for the subject EFCVs and that the proposed alternative meets the requirements of 10 CFR 50.55a(z)(1) by providing an acceptable level of quality and safety.
CONCLUSION
As described above, the NRC staff has determined that Alternative Request RR01 provides an acceptable level of quality and safety for the proposed testing and schedule for the EFCVs listed in section 1 of enclosure 1 of the submittal.
The NRCs authorization of the proposed alternative does not include any authorized changes to technical specification surveillance requirement 3.6.1.3.9 related to EFCV test frequency.
The NRC staff concludes that the licensee has adequately addressed all the regulatory requirements set forth in 10 CFR 50.55a(z)(1).
The NRC staff authorizes the use of Alternative Request RR01 for the Fifth 10-Year IST Program interval, which is scheduled to begin on June 1, 2024, and scheduled to end on May 31, 2034.
All other ASME OM Code requirements as incorporated by reference in 10 CFR 50.55a for which relief or an alternative was not specifically requested, and granted or authorized (as appropriate), in the subject request remain applicable.
Principal Contributors: Gurjendra S. Bedi, NRR
Hipolito Gonzalez, Chief Plant Licensing Branch 1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
cc: Listserv
ML24080A502 OFFICE NRR/DORL/LPL1/PM NRR/DORL/LPL1/LA NRR/DEX/EMIB/BC NAME AKlett KZeleznock SBailey DATE 03/20/2024 03/21/2024 03/06/2024 (TScarbrough for)
OFFICE NRR/DORL/LPL1/BC NAME HGonzález DATE 03/27/2024