ML24197A131
| ML24197A131 | |
| Person / Time | |
|---|---|
| Issue date: | 09/09/2024 |
| From: | Paul Laflamme Office of Nuclear Reactor Regulation |
| To: | Lisa Regner Office of Nuclear Reactor Regulation |
| References | |
| Download: ML24197A131 (1) | |
Text
September 9, 2024 MEMORANDUM TO:
Lisa Regner, Branch Chief Generic Communications and Operating Experience Branch Office of Nuclear Reactor Regulation FROM:
Paul LaFlamme, Reactor Systems Engineer Generic Communications and Operating Experience Branch Office of Nuclear Reactor Regulation
SUBJECT:
RESPONSE TO PUBLIC COMMENTS RECEIVED ON DRAFT NUREG-1022 REVISION 3 SUPPLEMENT 2, EVENT REPORT GUIDELINES 10 CFR 50.72(b)(3)(ii) and 10 CFR 50.73(a)(2)(ii)
The U.S. Nuclear Regulatory Commission (NRC) published a notice of opportunity for public comment on Draft NUREG-1022, Revision 3, Supplement 2, Event Report Guidelines 10 CFR 50.72(b)(3)(ii) and 10 CFR 50.73(a)(2)(ii), in Volume 89 of the Federal Register, page 27463 (89 FR 27463), on April 17, 2024. The NRC received comments from the Nuclear Energy Institute (Agencywide Documents Access and Management System (ADAMS)
Accession No. ML24173A005) and Nubar LLC (ML24173A259). Enclosed are the NRC responses to all public comments.
Enclosure:
NRC Responses to Public Comments Received CONTACT: Paul LaFlamme, NRR/DRO 301-415-1184 PAUL LAFLAMME Digitally signed by PAUL LAFLAMME Date: 2024.09.09 14:24:22 -04'00'
ML24197A131 NRR-106 OFFICE NRR/DRO/IOEB/SPM NRR/DRO/IOLB NRR/DRA/APOB NRRDRA/APOB NAME BBenney IBetts JHughey AZoulis DATE 7/22/2024 7/24/2024 7/22/2024 8/2/2024 OFFICE OGC NRR/DRO/IOEB NAME HBenowitz PLaFlamme DATE 7/30/2024 7/22/2024
Enclosure Analysis of Public Comments on DRAFT NUREG-1022, REVISION 3, SUPPLEMENT 2, EVENT REPORT GUIDELINES 10 CFR 50.72(b)(3)(ii) and 10 CFR 50.73(a)(2)(ii) (Agencywide Documents Access and Management System Accession No. ML24036A112)
Public comments are available electronically at the U.S. Nuclear Regulatory Commissions (NRCs) electronic reading room at http://www.nrc.gov/reading-rm/adams.html. The following two comments were received and analyzed by the NRC staff.
Letter No.
ADAMS Accession No.
Commenter Affiliation Commenter Name 1
ML24173A005 Nuclear Energy Institute (NEI)
ML24173A259 Nubar LLC Barry Quigley Each comment is identified by a primary number from the table above with subtopics identified by number.
Comment No. 1-1 Recommend additional discussion be included on the use of risk insights for determining if a condition significantly degrades plant safety. The discussion regarding Risk-Informed Safety Class (RISC)-3 and RISC-4 SSCs provides the licensee one method to use PRA and risk insights in evaluating applicable reporting requirements.
However, this approach can only be used for licensees with an approved 50.69 program, and for SSCs that have been categorized under 50.69. Licensees should also be given the option to use their detailed PRA models to provide insight regarding whether or not a condition significantly degrades plant safety.
NRC Response The NRC disagrees with this comment. Licensees are required to submit a license amendment request (LAR) to the NRC for approval to adopt the risk-informed categorization process described in 10 CFR 50.69. The process is a rigorous risk-informed process that includes both probabilistic risk assessment (PRA) and deterministic evaluations to determine the risk significance and appropriate categorization of structures, systems, and components (SSCs). Licensees that have categorized SSCs as Risk-Informed Safety Class (RISC)-3 and RISC-4 have been approved by the NRC to implement the requirements under 10 CFR 50.69. Therefore, adoption of the requirements and risk-informed methodologies associated with 10 CFR 50.69 by licensees that have received NRC approval to do so provides a reliable and efficient method for supporting decision-making regarding conditions that significantly degrade plant safety to determine reportability under 10 CFR 50.72 and 10 CFR 50.73 outside of compliance with 10 CFR 50.69.
An acceptable methodology and approach for licensees who have not adopted 10 CFR 50.69 for using detailed PRA models to provide insights for reportability is outside the scope of this supplement and would require significant additional stakeholder input.
However, the examples given in the NUREG supplement are risk-informed, even for licensees who have not adopted 10 CFR 50.69.
The NRC made no changes to the guidance as a result of this comment.
Comment No. 1-2 The commenter recommended certain edits to section 2.1.
NRC Response The NRC agrees with the comment and incorporated the suggested changes in section 2.1 as shown below.
the moment when a degraded or unanalyzed condition occurs, such as those discussed in the examples below, or is found to have occurred; or if the existence of a seriously degraded principal safety barrier or unanalyzed condition that significantly degrades plant safety cannot be readily determined when it occurs or when it is found to have occurred, and additional evaluation is needed, then the moment when the evaluation that supports the existence of such a condition is completed.
Comment No. 1-3 The commenter recommended certain edits to section 2.2.A.
NRC Response The NRC agrees with the comment and incorporated the suggested changes in section 2.2.A as shown below.
- 3. degradation of steam generator tubes that is deemed serious if the tubes fail to meet the performance criteria outlined in the plant specific technical specifications (TS) for steam generator tube integrity. When one or more steam generator tubes meet the tube repair criteria and have not been plugged or repaired in accordance with the steam generator program, they are not considered to be severely degraded as long as structural integrity and the accident-induced leakage performance criteria in the plant-specific TSs are met.
Comment No. 1-4 Recommend clarifying that functionally related components implies components from different systems. Also recommend replacing could with would to avoid any confusion or ambiguity when evaluating if a condition significantly degrades plant safety.
Section 2.2.B, Example #5:
o Proposed language:
- 5. Multiple functionally related safety-related components (i.e.
components in different systems) out of service that would prevent the fulfillment of a safety function.
NRC Response The NRC agrees, in part, with the comment and incorporated the changes as shown below:
Section 2.2.B, Example #5:
- 5. Multiple functionally related safety-related components that may be in different systems are out of service that could prevent the fulfillment of a safety function.
This example is intended to clarify that functionally related components in different systems that are out of service simultaneously could result in a reportable condition.
However, it is not meant to further imply that functionally related components in the same system that are out of service simultaneously could not result in a reportable condition.
Additionally, the example retains could for consistency with the language in the body of the rule covering preventing fulfillment of safety functions.
Comment No. 1-5 Recommend providing an example of a condition that is normal and expected wear or degradation.
Section 2.2.1, Example #4 o Proposed language:
(4) Additional Clarification for Events Not Required to Be Reported Licensees are not required to report an event pursuant to this criterion if the event results from a shared dependency among trains or channels that is a natural or expected consequence of the approved plant design, or normal and expected wear or degradation. For example, run to failure components would be considered normal and expected wear or degradation.
NRC Response The NRC agrees, in part, with the comment and incorporated some of the suggested changes as shown below. NRC chose to explain normal and expected wear differently than the wording suggested by this comment.
Section 2.2.1, Example #4 o Updated language:
(4) Additional Clarification for Events Not Required to Be Reported Licensees are not required to report an event pursuant to this criterion if the event results from a shared dependency among trains or channels that is a natural or expected consequence of the approved plant design, or normal and expected wear or degradation. For example, the failure due to normal and expected wear of components identified as acceptable in the licensee's maintenance program would not be reportable under this criterion.
Comment No. 2-1 Is it permissible to delay entry of the non-conforming condition into the corrective action program? Once entered into CAP, immediate and prompt operability decisions are required. Current guidance is 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for immediate and 3 days for prompt operability.
If a vendor finds a generic unanalyzed condition, there will be a line of licensees waiting for a determination of significantly degrading. What does the licensee tell the NRC resident inspector when they ask about operability on day 5 and the vendor has three more plants to analyze before they get to yours? In my experience, the reason this has not been a problem is that the vendor does not notify the licensee until the vendor has already completed the analyses to show the unanalyzed condition is acceptable; I do not agree with this approach. Even if it is related to a single plant, I have experienced a long iterative process as the we provided offsetting reduced conservatism inputs to the vendor and then waiting for acceptable results.
Consider an example. The thermal conductivity of interior coatings in containment is found to be non-exists should be promptly entered into CAP. It now must be evaluated for reportability and operability. Under the proposed change, the licensee can tell the resident inspector for reportability Were looking at it, well get back to you. The resident can then press on about operability where a were looking at it is not consistent with IMC Suggested resolution: Make conforming changes to NRC guidance on operability.
NRC Response The NRC disagrees with the comment. Licensees cannot delay entry of a non-conforming condition into the corrective action program (CAP) as a result of changes to this guidance. Licensees are required to submit the non-conforming condition into the approved CAP in accordance with site-specific procedures. The site-specific CAP procedures specify each licensees method for investigation, operability determinations, material and resource acquisitions, and resolution of non-conforming conditions. Event reporting for conditions that cannot immediately be identified as degraded or unanalyzed conditions are addressed in NUREG-1022, Revision 3, Supplement 2, section 2.1, Time of Discovery. If the degraded or unanalyzed conditions require further evaluation, then time of discovery starts when evaluation supports existence of such condition.
Operability determinations are made in accordance to limiting conditions for operation (LCO) specific to the licensees Technical Specifications required by 10 CFR 50.36. The LCOs are defined as the lowest functional capability or performance levels of equipment required for safe operation of the facility. Operability determinations are utilized whenever a condition calls into question the ability of structures, systems, and components (SSCs) to perform functions required for compliance to Technical Specifications. The operability determinations are independent of reportability conditions outlined in 10 CFR 50.72, 10 CFR 50.73, and NUREG-1022, Revision 3, Supplement 2.
The licensees are obligated to complete operability determinations promptly when aware of such conditions.
The NRC made no changes to the guidance as a result of this comment.
Comment No. 2-2 I saw quite a few unanalyzed conditions while in Operations and Design Engineering.
As I tended to have a more conservative view than others I studied NUREG-1022 and the statements of consideration closely. I would also consider reportability under 10CFR50.9. I noted that the footnote in NUREG-1022 says A licensee cannot evade the rule by never 'finding' information to be significant. The fact that a licensee considers information to be significant can be established, for example, by the actions taken by the licensee to evaluate that information.
I distinctly remember additional explanatory text saying that an example of significance would be having a vendor performing analyses (it may or not have included the word extensive, I dont recall.) However, I am retired and no longer have access to this additional explanatory text.
The proposed change allows the need for vendor analyses to delay reportability.
However, the need for vendor analyses could trigger reportability under 10CFR50.9.
Suggested Resolution - Explain when vendor analyses used for the proposed change rise to the level of of reportability under 10CFR50.9.
NRC Response The NRC disagrees with the comment. The information in 10 CFR 50.9 relates to regulated activities with significant implication to public health and safety events and the need for licensees to submit complete and accurate information to the NRC. Sections 50.72 and 50.73 are event reporting criteria. Section 50.9 issues that the licensee needs to consider are separate from 10 CFR 50.72 or 50.73 reportability criteria.
The NRC made no changes to the guidance as a result of this comment.
Comment No. 2-3 The federal register reference in footnote 1 is incorrect. The proper volume is 52, not
- 59.
NRC Response The NRC disagrees with the comment. Footnote 1 provides the sources of the paragraph reproduced in the text of NUREG-1022, Revision 3, Supplement 2, that concerns unanalyzed conditions significantly affecting plant safety. Those sources are the two Federal Register notices listed in footnote 1.
The NRC made no changes to the guidance as a result of this comment.