RBG-48237, Response to NRC Integrated Inspection Report 05000458/2023001
| ML23145A266 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 05/25/2023 |
| From: | Hansett P Entergy Operations |
| To: | NRC Region 4, Document Control Desk |
| References | |
| RBG-48237, IR 2023001 | |
| Download: ML23145A266 (1) | |
Text
Philip Hansett Site Vice President River Bend Station 225-381-4374 RBG-48237 May 25, 2023 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001
Subject:
Response to NRC Integrated Inspection Report 05000458/2023001 River Bend Station, Unit 1 NRC Docket No. 50-458 Renewed Facility Operating License No. NPF-47 Entergy Operations, Inc (Entergy) is respectfully contesting one Severity Level IV violation contained in Reference 1. The violation (Severity Level IV 05000458/2023001-05) cited Title 10 of the Code of Federal Regulations (10 CFR) 50.59 (c)(2)(viii), "Changes, Tests and Experiments," due to a failure to obtain a license amendment prior to implementing a proposed change. Specifically, the violation contends that Entergy changed the method for establishing the design basis of the standby diesel generator air start system capacity from eight starts of which five are 10-second starts to five starts with no specified time. The violation concludes that this departed from the approved method described in the standard review plan (Reference 2) and was implemented without agency approval.
Entergy maintains that a violation of 10 CFR 50.59 (c)(2)(viii) did not occur. 10 CFR 50.59 (c)(2)(viii) specifies that a license amendment shall be obtained for departures from a method of evaluation as described in the Updated Final Safety Analysis Report (UFSAR). NEI 96-07, Revision 1 (Reference 3) is the primary guidance document for compliance with 10 CFR 50.59 and has been endorsed by the Nuclear Regulatory Commission (NRC) in RG 1.187, Rev 3 (Reference 4). NEI-96-07 defines a method of evaluation as the calculational framework used for evaluating behavior or response of the facility or an SSC. The standard review plan provides NRC staff guidance to conduct reviews and is not a method of evaluation subject to 10 CFR 50.59 (c)(2)(viii).
Entergy agrees that a violation of 10 CFR 50.59 associated with a minor performance deficiency exists, however, it is not associated with a change that resulted in a departure from a method of evaluation. Entergy respectfully requests this violation be re-characterized as a failure to perform a 10 CFR 50.59 evaluation contrary to 10 CFR 50.59 (d)(1). A detailed review is provided in the enclosure to this letter.
River Bend Station 5485 U.S. Highway 61N, St Francisville, LA 70775
REG-48237 Page 2 of 2 This letter contains no new regulatory commitments. Should you have any questions regarding this submittal, please contact Randy Crawford, Manager Regulatory Assurance River Bend Station at 225-381-4177.
Sincerely, WW PH/dlw
Enclosure:
Response to NRC Integrated Inspection Report 05000458/2023001 Severity Level IV Violation 2023001-05
References:
- 1) NRC letter to Entergy, "River Bend Station Integrated Inspection Report 05000458/2023001 (ML231 169A235).
- 2) NUREG-OBOO. Revision 1. Standard Review Plan for the Review of Satety Analysis Reports for Nuclear Power Plants," dated July 1981.
- 3) NEI 96-07, Revision 1. "Guidelines for 10 CFR 50.59 Implementation,"
dated November 2000.
- 4) NRC Regulatory Guide 1.18?, Revision 3. Guidance for Implementation of 10 CFR 50.59, Changes, Tests, and Experiments, dated June 2021.
cc: NRC Senior Resident Inspectors RBS NRC Region IV Regionat Administrator NRC Project Manager - RBS
Enclosure RBG-48237 Response to NRC Integrated Inspection Report 05000458/2023001 Severity Level IV Violation 2023001-05
RBG-48237 Enclosure Page 1 of 6 Response to NRC Integrated Inspection Report 05000458/2023001 Severity Level IV Violation 2023001-05 Description of the Violation The River Bend Station (RBS) - Integrated Inspection Report 05000458/2023001 (Reference 1) contained a Severity Level IV Violation 05000458/2023001-05 for failure to obtain a license amendment prior to implementing a proposed change. This report stated, in part:
"The inspectors identified a Severity Level IV non-cited violation of Title 10 of the Code of Federal Regulations 50.59(c)(2)(viii), Changes, Tests and Experiments, when the licensee did not obtain a license amendment prior to implementing a proposed change which resulted in a departure from a method of evaluation described in the USAR used in establishing the design basis. Specifically, the licensee changed the method for establishing the design basis of the standby diesel generator air start system capacity from eight starts of which five are 10-second starts to five starts with no specified time.
This method departed from the approved method described in the standard review plan and was implemented without agency approval The inspection report stated the removal of the requirement to perform five 10-second starts departed from the method of evaluation described in the Updated Final Safety Analysis Report (UFSAR). Additionally, the method departed from the approved method described in the standard review plan (Reference 2) and was implemented without agency approval. Specifically, the report referenced NUREG-0800, Standard Review Plan 9.5.6, Revision 2,Section II.4.g which states:
As a minimum, the air starting system should be capable of cranking a cold diesel engine five times without recharging the receiver(s). The air starting system capacity should be determined as follows: (1) each cranking cycle duration should be approximately 3 seconds; (2) consist of two to three engine revolutions; or (3) air start requirements per engine start provided by the engine manufacturer; whichever air start requirement is larger.
The violation was issued in accordance with 10 CFR 50.59(c)(2)(viii) for a change that resulted in a departure from a method described in the UFSAR to establish the design basis but had not made an actual change to the system.
Description of the Change On September 22, 2022, Entergy implemented an engineering change which modified the River Bend UFSAR Section 9.5.6.1 and revised text for the diesel starting air system. The original text stated:
"Each redundant DGSS train is capable of providing the standby diesel generator with eight starts (five of them are 10 sec starts) from two air receivers without recharging the associated air receivers."
Entergy concluded this text was inconsistent with the original RBS Safety Evaluation Report (SER) documented in Reference 3. The change was implemented under 10 CFR 50.59 using only a Screening. No 10 CFR 50.59 evaluation was performed. The revised UFSAR Section 9.5.6.1 text stated:
RBG-48237 Enclosure Page 2 of 6 Response to NRC Integrated Inspection Report 05000458/2023001 Severity Level IV Violation 2023001-05 Each redundant DGSS train is capable of providing the standby diesel generator with five consecutive starts from two air receivers without recharging the associated air receivers.
This was a change to the design requirements for the capacity of the air start receiver.
Clarification of Entergy's Position In review of the findings, it is Entergys position that the violation inappropriately defines the standard review plan as a method of evaluation and that no methods of evaluation were changed.
10 CFR 50.59 permits licensees to make changes to the facility or procedures as described in its UFSAR, or conduct tests or experiments not described in its UFSAR, without first obtaining a license amendment pursuant to 10 CFR 50.90, Application for amendment of license, construction permit, or early site permit. Licensees can make these changes or conduct these tests or experiments without a license amendment only if a change to the facilitys technical specifications is not required, and if the change, test, or experiment does not meet any of the eight criteria listed in 10 CFR 50.59(c)(2).
Prior Nuclear Regulatory Commission (NRC) approval is required by 10 CFR 50.59(c)(2)(viii) if the change, test, or experiment would, Result in a departure from a method of evaluation described in the FSAR (as updated) used in establishing the design bases or in the safety analyses.
The definition in 10 CFR 50.59(a)(2) states the following:
"Departure from a method of evaluation described in the FSAR (as updated) used in establishing the design bases or in the safety analyses means:
(i) Changing any of the elements of the method described in the FSAR (as updated) unless the results of the analysis are conservative or essentially the same; or (ii) Changing from a method described in the FSAR to another method unless that method has been approved by NRC for the intended application."
Entergy's position is that no method of evaluation was changed and stating that NRC approval was required for a departure from a method of evaluation is incorrect. River Bend UFSAR Section 9.5.6 contains the design of the starting air system. Changes to the design of the starting air system are assessed as a change to the design function of the system.
Entergys Basis for Contesting NUREG-0800 (i.e., the Standard Review Plan or SRP) is not an evaluation methodology. As stated in NUREG-0800 Introduction Section, the SRP provides guidance for NRC staff to conduct reviews of operating license applications/requests for amendments with a principal purpose of assuring quality and uniformity of staff safety reviews. The SRP outlines design requirements and acceptance criteria to comply with the General Design Criteria (10 CFR 50
RBG-48237 Enclosure Page 3 of 6 Response to NRC Integrated Inspection Report 05000458/2023001 Severity Level IV Violation 2023001-05 Appendix A). The design bases for the River Bend air start system are contained in UFSAR Section 9.5.6. Under 10 CFR 50.59 changes to the design bases are assessed against the impact to the design function of the system.
The specific methods of evaluation that are used by River Bend are approved during the licensing process but are not specified in the SRP. No methods of evaluation are endorsed or approved by the SRP. Interpreting the SRP guidance as a method of evaluation would potentially require that Entergy consider the entire UFSAR as a method of evaluation. This interpretation does not follow endorsed industry or NRC guidance. SRP Section 9.5.6, Revision 2,Section II.4.g contains requirements for determining the capacity of the air starting system, however, as discussed below, these requirements do not meet the definition of method of evaluation.
NEI 96-07, Revision 1 (Reference 4) has been endorsed, with clarifications, as a method of compliance with 10 CFR 50.59 by the Nuclear Regulatory Commission (NRC) in RG 1.187, Rev 3 (Reference 5). Section 3.10 of NEI 96-07 defines Method of Evaluation as:
"Methods of evaluation means the calculational framework used for evaluating behavior or response of the facility or an SSC."
The NRC also uses IMC 0335 (Reference 6) for guidance to review changes made under 10 CFR 50.59. IMC 0335 is also based on NEI 96-07 and provides no significant differences between what is endorsed in RG 1.187. IMC 0335 does not provide new guidance for interpreting 10 CFR 50.59. Method of evaluation is defined similarly in IMC 0335 Section 04.03:
"The calculational framework used for evaluating behavior or response of the reactor/ISFSI/MRS, cask design, or any structure, system, and component (SSC)."
Generally, this means computer codes, calculations, correlations, etc., contained in the UFSAR Chapter 6 and 15 transient and accident analyses (safety analyses).
Further discussion is contained in NEI 96-07 Section 3.10:
Changes to such methods of evaluation require evaluation under 10 CFR 50.59(c)(2)(viii) only for evaluations used either in UFSAR safety analyses or in establishing the design bases, and only if the methods are described, outlined or summarized in the UFSAR.
RBG-48237 Enclosure Page 4 of 6 Response to NRC Integrated Inspection Report 05000458/2023001 Severity Level IV Violation 2023001-05 NEI 96-07 and IMC 0335 provide specific examples of what is included as an element of method for consideration under 10 CFR 50.59 (c)(2)(viii). The examples provided between NEI 96-07 and IMC 0335 are similar with no notable differences. These examples include, in part:
- Data correlations
- Heat transfer coefficients
- Mathematical models
- Decay Heat Models
- Specific assumptions in a computer program
- Vendor-specific thermal design procedures Finally, NEI 96-07 Section 3.10 concludes with further clarification of what is subject to 10 CFR 50.59 Criterion viii consideration:
- "Methods of evaluation used in analyses that demonstrate that design basis limits of fission product barriers are met (i.e., for the parameters subject to criterion 10 CFR 50.59(c)(2)(vii))
- Methods of evaluation used in UFSAR safety analyses, including containment, ECCS and accident analyses typically presented in UFSAR Chapters 6 and 15, to demonstrate that consequences of accidents do not exceed 10 CFR 100 or 10 CFR 50, Appendix A, dose limits
- Methods of evaluation used in supporting UFSAR analyses that demonstrate intended design functions will be accomplished under design basis conditions that the plant is required to withstand, including natural phenomena, environmental conditions, dynamic effects, station blackout and ATWS."
As can be seen from the discussion in NEI 96-07, 10 CFR 50.59 (c)(2)(viii) is focused on the calculations used to determine plant response in UFSAR safety analyses.
In response to the specific change made to the River Bend UFSAR, no method of evaluation was changed. Violation 05000458/2023001-05 is related to a change to the design requirements for the capacity of the air start system in Section 9.5.6.1 of the River Bend UFSAR. River Bend UFSAR Section 9.5.6 closely follows SRP Section 9.5.6 which establishes starting system design features for reliable emergency diesel engine starting following a loss of offsite power. The requirements stated in SRP Section 9.5.6 are provided as means to meet independence and redundancy criteria specified in GDC 17.
Based on the definition in NEI 96-07, methods of evaluation could be found outside of UFSAR Chapters 6 and 15 if a method is used in establishing the design basis. This provision is only applicable to calculational framework that would be used in establishing design basis (mathematical models, data correlations, specific limitations of computer programs). Review of UFSAR Section 9.5.6.1 shows no mathematical models, data correlations, computer programs,
RBG-48237 Enclosure Page 5 of 6 Response to NRC Integrated Inspection Report 05000458/2023001 Severity Level IV Violation 2023001-05 etc., were used for establishing the air start capacity requirements. Changes to the capacity of the air start system would be assessed as a change to a design function. The change to UFSAR Section 9.5.6.1 would be subject to 10 CFR 50.59(c)(2) but the evaluation of 10 CFR 50.59(c)(2)(viii) would conclude that the change does not involve a method of evaluation.
Therefore, based on the above, there is no violation of 10 CFR 50.59(c)(2)(viii).
Characterization of 05000458/2023001-05 Entergy implemented the engineering change which modified the RBS UFSAR Section 9.5.6.1 under 10 CFR 50.59 and only performed a 50.59 screening. If performed correctly, the screening should have identified that the change to the air start capacity would adversely affect the design function and would have resulted in the performance of a 50.59 evaluation which would document a review of the change against each of the criteria in 10 CFR 50.59(c)(2). It is Entergy's position that it is not appropriate to characterize the violation against 10 CFR 50.59 (c)(2)(i-vii) because the results of an evaluation cannot be pre-determined and, as discussed above, a violation against 10 CFR 50.59(c)(2)(viii) is not appropriate because the change did not involve a method of evaluation. For these reasons, Entergy respectfully requests that this violation be characterized as a failure to document a written evaluation, which would be in violation of 10 CFR 50.59 (d)(1), which states the following:
"The licensee shall maintain records of changes in the facility, of changes in procedures, and of tests and experiments made pursuant to paragraph (c) of this section. These records must include a written evaluation which provides the bases for the determination that the change, test, or experiment does not require a license amendment pursuant to paragraph (c)(2) of this section."
Entergy is evaluating the following options to restore compliance with 10 CFR 50.59 (d)(1):
a) Perform a 50.59 evaluation in accordance with Entergys procedure, EN-LI-101 10 CFR 50.59 Evaluations
- i. If the result of the evaluation determines that prior NRC approval is not needed, then Entergy would report a summary of the evaluation to the NRC in accordance with 10 CFR 50.59 (d)(2) ii. If the result of the evaluation determines that prior NRC approval is needed, then Entergy would submit the proposed change as a license amendment request pursuant to 10 CFR 50.90 b) Restore River Bend UFSAR Section 9.5.6.1 to its original text before the change was made:
"Each redundant DGSS train is capable of providing the standby diesel generator with eight starts (five of them are 10 sec starts) from two air receivers without recharging the associated air receivers."
RBG-48237 Enclosure Page 6 of 6 Response to NRC Integrated Inspection Report 05000458/2023001 Severity Level IV Violation 2023001-05 Conclusion The SRP Section 9.5.6, Revision 2,Section II.4.g requirements for determining the capacity of the air starting system is not a method of evaluation. The change to River Bend UFSAR Section 9.5.6.1 did not change a method of evaluation, as defined in endorsed NRC and industry guidance. 10 CFR 50.59(c)(2)(viii) is not applicable to this scenario. It is Entergys position that violation 05000458/2023001-05 should be assessed against 10 CFR 50.59 (d)(1) for the failure to document a written evaluation.
References:
- 1) NRC letter to Entergy, "River Bend Station - Integrated Inspection Report 05000458/2023001 (ML231169A235).
- 2) NUREG-0800, Revision 1, Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants," dated July 1981.
- 3) NUREG-0989, "Safety Evaluation Report related to the operation of River Bend Station," May 1984.
- 4) NEI 96-07, Revision 1, "Guidelines for 10 CFR 50.59 Implementation,"
dated November 2000.
- 5) NRC Regulatory Guide 1.187, Revision 3, "Guidance for Implementation of 10 CFR 50.59, "Changes, Tests, and Experiments,""
dated June 2021.
- 6) NRC Inspection Manual Chapter 0335, "Changes, Tests, and Experiments," dated February 2021.