ML22349A658

NEI Responses to NRC Comments on Draft NEI 99-01, Revision 7, Developments of EALs for Non-Passive Reactors

ML22349A658
Person / Time
Site:	Nuclear Energy Institute
Issue date:	12/14/2022
From:	Young D Nuclear Energy Institute
To:	Raymond Hoffman Office of Nuclear Security and Incident Response
References
EPID L-2021-NGF-0003
Download: ML22349A658 (1)

Text

From: Siva Lingam To: Siva Lingam

Subject:

RE: Responses to NRC staff comments on NEI 99-01, Revision 7, Draft G Date: Sunday, December 11, 2022 5:14:02 PM From: YOUNG, David <dly@nei.org>

Sent: Friday, October 14, 2022 11:09 AM To: Raymond Hoffman <Raymond.Hoffman@nrc.gov>

Cc: Kathryn Brock <Kathryn.Brock@nrc.gov>; Clay Johnson <Clay.Johnson@nrc.gov>; Fanta Sacko

<Fanta.Sacko@nrc.gov>; Leslie Fields <Leslie.Fields@nrc.gov>

Subject:

[External_Sender] Responses to NRC staff comments on NEI 99-01, Revision 7, Draft G

Ray, Good morning.

The NEI task force working on NEI 99-01, Revision 7, has completed its review of the NRC staff comments provided to us during the public meeting on 10/5/22. The staff comments are available in ADAMS - see ML22277A444. Our responses to those comments are presented below.

Comment #1: The task force agrees with the comment and section 1.2 was removed.

Comment #2: The task force agrees with the comment and added the requested sentence to section 2.3.

Comment #3: The task force agrees with the comment and added the requested discussion as new section 4.4.

Comment #4: The task force agrees with the comment and made the requested text change to FPB Developer Note 2.

Comment #5: The task force agrees with the comment; however, it was determined that a threshold based on SAMG entry for PWRs would not provide the desired diversity of indications since entry primarily relies on meeting specified core exit thermocouple (CET) readings. Instead, the task force added a new Fuel Clad Loss threshold based on a reactor vessel level reading and revised the existing Potential Loss reactor vessel level threshold to align with the new Loss threshold. This meets the intent of the staff comment to have indications based on diverse RCS instrumentation (i.e., CETs and reactor vessel level) to assess both a Loss and Potential Loss of the Fuel Clad Barrier.

Comment #6 - The task force determined that the proposed change would not be beneficial to an emergency classification scheme and did not incorporate it. The reasons for this conclusion are below.

1. The PWR FPB table presented in Draft G, and as revised as described in the response to Comment #5 above, specifies a diverse set of safety-related RCS indications to assess the status of the RCS

and Fuel Clad Barriers. The specified indications are found in emergency operating procedures and used by plant operators to identify RCS leakage (supporting RCS Barrier assessments) and challenges to the core cooling safety function (supporting Fuel Clad Barrier assessments). Further, the indications are subject to the requirements in 10 CFR 50.65 (aka the Maintenance Rule) and thus highly reliable. We believe the use of RCS indications is the optimum approach for assessing these barriers. Thresholds based on containment radiation monitors or RCS sampling have known limitations (associated with accuracy and timeliness, respectively) and are not ideal for barrier status assessments.

2. The task force is concerned that adding offsite dose projection-based thresholds for the Fuel Clad and RCS Barriers could cause confusion during an emergency classification. For example, adding the existing values specified in the dose projection EALs (AA1 and AS1) to the FPB table would result in having to track the same values in two locations. And lowering the AA1 and AS1 values for placement in the FPB table would result in different dose-based threshold values for the same classification level (e.g., 10 mrem TEDE in AA1 and a lowered value for FA1 as presented in the RCS Loss or Potential Loss column). The new offsite dose-based thresholds added to the Containment Barrier Potential Loss column in Draft G are different in that they are escalatory thresholds to a General Emergency and indicate that a significant release has occurred. In this sense, they fit logically into the FPB table because, as noted in Comment #6, its reasonable to assume that both the RCS and Fuel Clad Barriers would already be lost.

For these reasons, the task force believes that the specified RCS indications are sufficient for assessing the status of the Fuel Clad and RCS Barriers, and that offsite dose-based thresholds for requiring an Alert or SAE should remain solely in the EALs AA1 and AS1.

Following your review of these responses, please let me know if another public meeting is needed to discuss the above comments or if NEI should proceed with submitting the final version of NEI 99-01, Revision 7, to the NRC for endorsement.

David Young l Senior Technical Advisor Security and Incident Preparedness Nuclear Energy Institute (202) 739-8127 This electronic message transmission contains information from the Nuclear Energy Institute, Inc. The information is intended solely for the use of the addressee and its use by any other person is not authorized. If you are not the intended recipient, you have received this communication in error, and any review, use, disclosure, copying or distribution of the contents of this communication is strictly prohibited. If you have received this electronic

transmission in error, please notify the sender immediately by telephone or by electronic mail and permanently delete the original message. IRS Circular 230 disclosure: To ensure compliance with requirements imposed by the IRS and other taxing authorities, we inform you that any tax advice contained in this communication (including any attachments) is not intended or written to be used, and cannot be used, for the purpose of (i) avoiding penalties that may be imposed on any taxpayer or (ii) promoting, marketing or recommending to another party any transaction or matter addressed herein.