ML24164A219
| ML24164A219 | |
| Person / Time | |
|---|---|
| Issue date: | 06/12/2024 |
| From: | Eric Schrader Policy and Oversight Branch |
| To: | |
| References | |
| Download: ML24164A219 (1) | |
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Summary of IC and EAL Change Comments and Questions in NEI 99-01 Revision 7 The table below summarizes the changes made to the Initiating Conditions and Emergency Action Levels found to be unacceptable or have editorial corrections needed Rev. 6 IC and EAL#
Rev. 6 Wording Change Summary/Basis for Deletion NRC Comments FPB Table 9-F-3 Fuel Clad Barrier Potential Loss 2.B B. Inadequate RCS heat removal capability via steam generators as indicated by (site-specific indications).
Threshold deleted because the condition does not present an immediate threat to Fuel Clad Barrier.
During this condition, operators (following EOPs) will initiate a feed and bleed cooldown of the RCS.
Absent additional failure this cooldown method is sufficient to prevent challenge of Fuel Clad Barrier.
Do not agree that this is not indicative of an immediate threat to the FC Barrier. Rev 6 states, This condition warrants a Site Area Emergency declaration because inadequate RCS heat removal may result in fuel heat-up sufficient to damage the cladding and increase RCS pressure to the point where mass will be lost from the system. The staff believes the quoted statement above remains a true statement.
Inadequate RCS heat removal capability needs to remain a possible logic progression/escalation declaration.
Consider addition of a note to the Matrix Table and on the EAL Wallboard like: For FC PL 2.B and RCS PL 2.A - These criteria are not applicable if operators are intentionally reducing the heat removal capability of steam generators per EOPs, i.e., feed and bleed.
Note this is how we have it now, just without the note on the Wallboard so the decision-maker can make the correct, informed decision.
Implementing a feed and bleed EOP would not change the damage/potential damage already inflicted by the inadequate RCS heat removal capability via steam generators. As described in the Rev 6 quote above this condition warrants an SAE declaration.
Summary of IC and EAL Change Comments and Questions in NEI 99-01 Revision 7 Rev. 6 IC and EAL#
Rev. 6 Wording Change Summary/Basis for Deletion NRC Comments IC SU2 EAL #1 UNPLANNED loss of Control Room indications for 15 minutes or longer.
This IC and EAL is unnecessary as the condition presents a very low safety risk to the public.
A site can assess equipment failure(s) and identify and implement necessary corrective/compensatory measures without mobilizing the ERO Some plant response actions may also be required by Technical Specifications.
This condition would lead to a 10 CFR 50.72 report to the NRC and, depending on concurrent events or resulting impacts, may necessitate an emergency declaration under another IC.
Should this condition occur in conjunction with a reactor trip or ECCS (SI) actuation, then an Alert would be declared in accordance with IC SA2.
Sets wrong understanding/perception that all UE can go away.
needing to activate the Eplan. However if escalation or Eplan activation is warranted there are other EALs that would be considered for declaration.
Some plant response actions may also be required by Technical Specifications.
This condition would lead to a 10 CFR 50.72 report to the NRC and, depending on concurrent events or resulting impacts, may necessitate an emergency declaration under another IC.
Summary of IC and EAL Change Comments and Questions in NEI 99-01 Revision 7 Rev. 6 IC and EAL#
Rev. 6 Wording Change Summary/Basis for Deletion NRC Comments IC SS5 Inability to shutdown the reactor causing a challenge to (core cooling
[PWR] / RPV water level
[BWR]) or RCS heat removal.
IC and EALs are unnecessary - classification of this condition is addressed by the Fission Product Barrier (FPB) table thresholds.
Do not agree with deleting this EAL. The primary concern is the failure of RPS to work as designed. A failure of RPS to initiate or complete an automatic shutdown, failure of operator manual actions to shutdown the reactor, and continued power generation challenges the capability to adequately remove heat from the core and/or the RCS. SS5 addresses the fact that the Recognition Category F ICs/EALs do not address the additional threat posed by a failure to shutdown the reactor. Gross failure of RPS or ECCS are primary considerations for when to implement the Eplan i.e. EAL declaration. The NRC does not consider the criteria within the FPB matrix to be ICs or EALs. As stated in the NEI 99-01 Revision 6 Final Regulatory Analysis (ML13008A736), This IC set includes three ICs (FA1/FS1/FG1) which rely upon numerous criteria as logic inputs to determine the appropriate emergency classification based upon the number of lost and/or potentially lost fission product barriers. Nuclear Steam Supply System (NSSS) designs include three fission product barriers: fuel cladding, the RCS, and the containment. The criteria specified within this set define when each fission product barrier has been potentially lost or lost as appropriate for a BWR and a PWR.
Rev 6 makes the following statement, In some instances, the emergency classification resulting from this IC/EAL may be higher than that resulting from an assessment of the plant responses and symptoms against the Recognition Category F ICs/EALs. This is appropriate in that the Recognition Category F ICs/EALs do not address the additional threat posed
Summary of IC and EAL Change Comments and Questions in NEI 99-01 Revision 7 The two conditions in EAL statement (1).c entail a Potential Loss or Loss of both the Fuel Clad Barrier and the RCS Barrier; this condition would lead to a FPB Table Site Area Emergency declaration, regardless of ATWS.
Removing IC SS5 simplifies the emergency classification process.
by a failure to shutdown the reactor. The inclusion of this IC and EAL ensures the timely declaration of a Site Area Emergency in response to prolonged failure to shutdown the reactor. The NRC staff continues to believe that as stated in the previous quote the inclusion of this IC and EAL ensures the timely declaration of a Site Area Emergency in response to prolonged failure to shutdown the reactor.
BWR FC PL 2.A and RCS loss 2.A both state in the Basis, In high-power ATWS/failure to scram events, EOPs may direct the operator to deliberately lower RPV water level to the top of active fuel in order to reduce reactor power. RPV water level is then controlled between the top of active fuel and the Minimum Steam Cooling RPV Water Level (MSCRWL). Although such action is a challenge to core cooling and the Fuel Clad barrier, the immediate need to reduce reactor power is the higher priority. For such events, ICs SA5 or SS5 will dictate the need for emergency classification. As described in the previous quote SS5 dictates the needed for escalation to an SAE declaration.
Do not agree that removing will simplify the EAL classification process.