ML24079A292
| ML24079A292 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 03/21/2024 |
| From: | Marshall M Plant Licensing Branch 1 |
| To: | Constellation Energy Generation |
| Sreenivas V, NRR/DORL/LPLI, 415-2597 | |
| Shared Package | |
| ML24079A301 | List: |
| References | |
| EPID L-2022-LLA-0140 | |
| Download: ML24079A292 (6) | |
Text
Official Use Only - Proprietary Information.
1 Official Use Only Proprietary Information.
SUBJECT:
Limerick Generating Station, Units 1 and 2 - Draft Request for Additional Information Regarding Limerick Digital Instrumentation and Controls License amendment Request (EPID L-2022-LLA-0140)
Hello Frank and Ashley, By letter dated September 26, 2022 (Agencywide Documents Access and Management System Accession No. ML22269A569; non-public), as supplemented by letters dated August 12, 2022 (ML22224A149), November 29, 2022 (ML22333A817), February 8, 2023 (ML23039A141),
February 15, 2023 (ML23046A266), March 30, 2023 (ML23089A324), April 5, 2023 (ML23095A223), June 26, 2023 (ML23177A224), July 31, 2023 (ML23212B236),
September 12, 2023 (ML23255A095), October 30, 2023 (ML23303A223), November 21, 2023 (ML23325A206), January 26, 2024 (ML24026A296), and February 26, 2024 (ML24057A427),
Constellation Energy Generation, LLC (Constellation; the licensee) submitted license amendment requests to replace the Limerick Generating Station, Units 1 and 2 (Limerick) existing safety-related analog control systems with a single digital control system called plant protection system. The supplement dated September 12, 2023 replaced in its entirety the original license amendment requests dated September 26, 2023. The licensee replaced the original submittal, because it had mistakenly included proprietary information in the non-proprietary parts of the requests. The U.S. Nuclear Regulatory Commission (NRC) staff made all of the original submittal non-public. With the exceptions noted by the licensee in its letter dated September 26, 2023, the content of the replacement and the original are the same.
The proposed amendment requests would change both the design and technical specifications to permit the use of a new single digital instrumentation and controls system to replace analog instrumentation of reactor protection system, analog nuclear steam supply shutoff system, emergency core cooling system, reactor core isolation cooling system, and end-of-cycle recirculation pump trip at Limerick. In addition, the proposed amendments would change the classification of the redundant reactivity control system from safety-related to non-safety-related, eliminate the automatic redundant reactivity control system feedwater runback function, eliminate the automatic isolation function for the turbine enclosure main steam line tunnel temperature high indication, eliminate several surveillance requirements, and allow the use of automated operator aids (or automated controls) from main control room.
The NRC staff has reviewed the information provided in the license amendment request and has determined that additional information is needed to complete its review. This request for additional information (RAI) was discussed with you via exchange of emails dated March 18 and 19, 2024. It was agreed that Constellations response would be provided within 45 days of the date of this email.
RAIs 1 to 4 and 5 to 8 were provided to Constellation in separate emails dated January 26, 2024 and February 16, 2024, respectively. The review is ongoing, and the NRC staff may have additional RAIs.
- 9. (OI 60) For nuclear power plants with construction permits issued after January 1, 1971, but before May 13, 1999, Section 50.55a(h), Protection and safety systems, of Title 10 of the Code of Federal Regulations (10 CFR), requires, in part, that protection systems meet the requirements in Institute of Electrical and Electronic Engineers (IEEE) Std 279-1971, Criteria for Protection Systems for Nuclear Power Generating Stations. Limerick received
Official Use Only - Proprietary Information.
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construction permits on May 19, 1974, therefore its protection system has to meet the requirements in IEEE Std 279-1971. Clause 4.4 of IEEE Std 279-1971, Equipment Qualification, states that type test data or reasonable engineering extrapolation based on test data shall be available to verify that protection system equipment will be capable of meeting, on a continuing basis, the performance requirements determined to be necessary for achieving the system requirements.
General Design Criterion (GDC) 22, Protection System Independence, in Appendix A to 10 CFR Part 50 requires that the effects of natural phenomena, and of normal operating, maintenance, testing, and postulated accident conditions on redundant channels do not result in loss of the protection function. GDC 24, Separation of Protection and Control Systems requires that the protection system shall be separated from control systems to the extent that failure of any single control system component or channel, or failure or removal from service of any single protection system component or channel which is common to the control and protection systems leaves intact a system satisfying all reliability, redundancy, and independence requirements of the protection system. Interconnection of the protection and control systems shall be limited so as to assure that safety is not significantly impaired.
To meet the above regulatory requirements, the Class 1E to non-Class 1E isolation qualification testing should ensure any failure of non-Class 1E devices interfacing with Class 1E equipment will not impair the safety function of the Class 1E equipment. In Section 4.0 of to its letter dated September 12, 2023, the licensee stated that Regulatory Guide (RG) 1.209, Guidelines for environmental Qualification of Safety-Related Computer-Based Instrumentation and Control Systems in Nuclear Power Plants and RG 1.75, Physical Independence of Electric Systems are applicable to the to the license amendment request. The licensee does not clearly indicate which portions, if any, of the guidance in these guides are used in its equipment qualification efforts.
In Section 4 of the Licensing Technical Report included with Constellations letter dated September 12, 2023, the licensee states, in part, that the Class 1E isolation circuits will be tested to the Limerick fault requirements to show compliance to IEEE Std. 384. However, the proposed license amendment request, including the Qualification Summary Report for the Plant Protection System Upgrade for Limerick Units 1 and 2 (Qualification Summary Report) included with the licensees letter dated January 26, 2024 does not include summary description of the Class 1E to non-Class 1E isolation testing result for the plant protection system (PPS).
Please provide summary description of the qualification testing of the Class 1E to non-Class 1E isolation barriers used for the Limerick PPS.
- 10. (OIs 61, 64, and 76) For nuclear power plants with construction permits issued after January 1, 1971, but before May 13, 1999, Section 50.55a(h) of 10 CFR, requires, in part, that protection systems meet the requirements in IEEE Std 279-1971. Limerick received construction permits on May 19, 1974, therefore its protection system has to meet the requirements in IEEE Std 279-1971. Clause 4.4 of IEEE Std 279-1971 states that type test data or reasonable engineering extrapolation based on test data shall be available to verify that protection system equipment will be capable of meeting, on a continuing basis, the performance requirements determined to be necessary for achieving the system requirements.
Official Use Only - Proprietary Information.
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In Table 2.3-3 of Qualification Summary Report, the licensee lists some critical hardware components in the PPS test specimen cabinets. In Section 2.2.3 of the Qualification Summary Report, the licensee states, to simulate the production PPS equipment, the equipment qualification (EQ) test specimen layout and functionality were designed to represent the functions of the full system. It appears that the summary results for all the components included in the PPS test specimen cabinets EQ-1 and EQ-2 are not included in the Qualification Summary Report.
a) It appears that other critical hardware components in the PPS test specimen cabinets EQ-1 and EQ-2, which are shown on Figure 2.3-2 of Qualification Summary Report are not included in Table 2.3-3, such as component interface module and its associated components, high amperage relay panel, and associated circuit parts, such as Ovation analog input modules, sequence of events modules, and remote interface modules.
Please provide the part numbers and product revisions for the components listed above that were included as part of the PPS test specimen cabinets EQ-1 and EQ-2 qualified for the Limerick digital modernization project.
b) The ((
)), which is not part of the approved generic Common Q platform, is included in the proposed Limerick PPS and cabinet testing. A summary description of qualification testing results is not in the license amendment request, including the Qualification Summary Report.
Please provide summary description of qualification results for the ((
)).
c) The Sola DC/AC converter, which is not part of the approved generic Common Q platform, is included in the cabinet testing. A summary description of the qualification testing results in not in the license amendment request, including the Qualification Summary Report. It is not clear from the license amendment request if the Sola DC/AC converter is part of the proposed Limerick PPS.
Please clarify if the Sola DC/AC converter is part used in the PPS. If yes, please provide its summary description of qualification results.
- 11. For nuclear power plants with construction permits issued after January 1, 1971, but before May 13, 1999, Section 50.55a(h) of 10 CFR, requires, in part, that protection systems meet the requirements in IEEE Std 279-1971. Limerick received construction permits on May 19, 1974, therefore its protection system has to meet the requirements in IEEE Std 279-1971.
Clause 4.4 of IEEE Std 279-1971, states that type test data or reasonable engineering extrapolation based on test data shall be available to verify that protection system equipment will be capable of meeting, on a continuing basis, the performance requirements determined to be necessary for achieving the system requirements.
a) In Section 4.4.2 of Qualification Summary Report the license stated evaluation identified 51 differences in the production hardware (in comparison to the EQ test specimens) that require further evaluation and the licensee stated An evaluation/analysis shall be performed by equipment qualification engineers to determine if any of the identified hardware is qualified by previous testing and/or analysis; otherwise, additional testing shall be performed to qualify the remaining
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the PPS shall meet RG 1.180, Revision 2. In Section 3.3.1, the licensee stated that EMC testing was performed in accordance with both the Electric Power Research Institute (EPRI)
Topical Report TR-102323 and RG 1.80. The regulatory guidance in RG 1.180, Rev. 2 states that regardless of which susceptibility testing program is chosen, either set of test methods (i.e., MIL-STD-461G or IEC 610000-4) should be applied in its entirety, without selective application of individual methods (i.e., no mixing and matching of test methods). It appears from the discussion in the Qualification Summary Report that there was selective application of the individual methods.
Please provide justification to support or clarification regarding the deviation from the guidance in RG 1.180 regarding the mixed use of IEC 61000-4-3 and MIL-STD-416G, RS103 tests. Also, describe any other deviations from guidance in RG 1.180.
- 13. For nuclear power plants with construction permits issued after January 1, 1971, but before May 13, 1999, Section 50.55a(h) of 10 CFR requires that protection systems meet the requirements in IEEE Std 279-1971 Limerick received construction permits on May 19, 1974, therefore its protection system has to meet the requirements in IEEE Std 279-1971 In Section 4.0 of Attachment 1 of its letter dated September 12, 2023, the licensee stated that RG 1.209 is applicable to the license amendment request. The licensee does not clearly indicate which portions, if any, of the guidance in this guide is used in its equipment qualification efforts. Section 5 of EPRI TR-107330 which is endorsed in RG 1.209 includes guidance on acceptance and operability testing. In Section 2.3.3 of EQ Summary Report, the licensee states that procedures also included baseline functional tests to check the performance of the EQ PPS system before and after the EQ tests were performed. The actual conditions achieved during pre-test and post-test were not included in Table 3.2-2.
Please provide the actual conditions achieved or a justification for the absence of the pre-test and post-test for the component environmental testing.
- 14. (OI 55) For nuclear power plants with construction permits issued after January 1, 1971, but before May 13, 1999, Section 50.55a(h) of 10 CFR requires that protection systems meet the requirements in IEEE Std 279-1971. Limerick received construction permits on May 19, 1974, therefore its protection system has to meet the requirements in IEEE Std 279-1971.
Clause 4.4 of IEEE Std 279-1971 states that type test data or reasonable engineering extrapolation based on test data shall be available to verify that protection system equipment will be capable of meeting, on a continuing basis, the performance requirements determined to be necessary for achieving the system requirements.
The NRC staffs evaluation of the Common Q platform topical report identified plant-specific action items (PSAIs) related to communication that must be addressed by an applicant when requesting NRC approval for installation of a safety-related system based on the Common Q platform topical report. In the approved topical report, PSAI 20 states licensee implementing an application based upon the Common Q platform that utilizes fiber optic cables to connect high speed links [HSL] between safety divisions shall ensure that all plant-specific environmental qualification requirements for this cabling are met.
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