ML24298A138

Final RAI for FitzPatrick JAFP-24-0047 (L-2024-LLA-0134)

ML24298A138
Person / Time
Site:	FitzPatrick
Issue date:	10/24/2024
From:	Lantigua R Plant Licensing Branch 1
To:	Reynolds R Constellation Energy Generation
Poole J
References
EPID L-2024-LLA-0134
Download: ML24298A138 (4)

Text

From: Ricardo Lantigua To: Reynolds, Ronnie J: (Constellation Nuclear)

Cc: Audrey Klett

Subject:

FINAL RAI for FitzPatrick JAFP-24-0047 (L-2024-LLA-0134)

Date: Thursday, October 24, 2024 12:30:00 PM Attachments: FINAL RAI for FitzPatrick JAFP-24-0047 (L-2024-LLA-0134).pdf

Ron,

Please see the attached file with the RAIs for the subject LAR. Per our clarification call today, the responses due date is 10/29/2024. No other changes were made since the draft other than the dates.

Thanks and have a good weekend,

Ricardo Lantigua, Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Division of Operating Reactor Licensing Plant Licensing Branch 1

REQUEST FOR ADDITIONAL INFORMATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION LICENSE AMENDMENT REQUEST FOR ROD WORTH MINIMIZER TECHNICAL SPECIFICA TIONS CONSTELLATION ENERGY GENERATION, LLC JAMES A. FITZPATRICK NUCLEAR POWER PLANT DOCKET NO. 50-333 EPID L-2024-LLA-0134 ISSUE DATE: October 24, 2024

=

Background===

By application dated September 25, 2024 (Agencywide Documents Access and Management System Accession No. ML24269A132), Constellation Energy Generation, LLC (CEG, the licensee) submitted a license amendment request (LAR) to change the Technical Specifications (TS) for the James A. FitzPatrick Nuclear Power Plant (JAF)

Renewed Facility Operating License DPR-59. The licensee requested to change TS 3.3.2.1 Condition C for the operability of the rod worth minimizer ( RWM) during reactor startup. The change would add a footnote to TS 3.3.2.1 required action C.2.1.2 to permit reactor startup with the RWM inoperable while an additional compensatory measure is implemented. The footnote would expire on December 31, 2024.

The U.S. Nuclear Regulatory Commission (NRC) staff has reviewed the information provided by the licensee in its application and has determined that the staff needs the following additional information to complete its review of the LAR. As discussed with licensee staff on October 24, 2024, NRC is requesting the licensee to respond to the request for additional information (RAI) on or by October 29, 2024.

Regulatory Basis

Title 10 of the Code of Federal Regulations (10 CFR), Part 50, Appendix A, general design criterion (GDC) 10, Reactor design, states that the reactor core and associated coolant, control, and protection systems shall be designed with appropriate margin to assure that specified acceptable fuel design limits are not exceeded during any condition of normal operation, including the effects of anticipated operational occurrences.

10 CFR 50, Appendix A, GDC 28, Reactivity limits, states that the reactivity control systems shall be designed with appropriate limits on the potential amount and rate of reactivity increase to assure that the effects of postulated reactivity accidents can neither (1) result in damage to the reactor coolant pressure boundary greater than limited local yielding nor (2) sufficiently disturb the core, its support structures or other reactor pressure vessel internals to impair significantly the capability to cool the core. These postulated reactivity accidents shall include consideration of rod ejection (unless prevented by positive means), rod dropout, steam line rupture, changes in reactor coolant temperature and pressure, and cold water addition.

1

RAI-1

The application states:

Control rod withdrawal errors are considered when the reactor is at power levels below the power range. The most severe case occurs when the reactor is just critical at room temperature and an out-of-sequence rod is continuously withdrawn. Procedural controls supplemented by the RWM would normally prevent withdrawal of such a rod. It is assumed that the Intermediate Range Neutron Monitoring (IRM) channels are in the worst conditions of allowed bypass. The scaling arrangement of the IRMs is such that for unbypassed IRM channels a SCRAM signal is generated before the detected neutron flux has increased by more than a factor of ten. In addition, a high neutron flux SCRAM is generated by the average power range monitors.

This statement is also found in the description of analyzed abnormal operational transients in the Updated Final Safety Analysis Report (UFSAR), section 14.5.4.2, Continuous Rod Withdrawal During Startup. UFSAR section 14.4.1, Approach to Safety Analyses - General, also assumes that this abnormal operational transient does not result in fuel damage.

Provide a justification as to whether an inoperable RWM during this abnormal operational transient can result in any calculated damage to the fuel.

RAI-2

The application states:

In considering the possibilities of a control rod drop accident, only the rod worths of the lower curve of UFSAR Figure 14.6 -1 are pertinent at less than 10 percent power. These are the rods which are normally allowed to be moved by operating procedures and the RWM. The nonscheduled rods, those within the central envelope, do not have a withdrawal permissive during the time their worths are greater than the lower curve, so they are held full in by the control rod drive and cannot drop from the core. If a nonscheduled rod were selected, the RWM blocks rod movement.

The application also states:

The control rod drop accident is defined as the assumed drop of the highest worth rod that can be developed at any time in core life or plant operating conditions by one error on the part of the operator. The RWM, which would normally prevent the operator from moving this rod, is assumed not to function.

2 The NRC staff is requesting the following information to understand the existing failure modes of the RWM and how they relate to the analysis for the control rod drop accident.

a. Provide a justification for crediting the RWM blocking nonscheduled rod movement given the continuing unreliability of the RWM system or describe other means used to minimize the consequences of a control rod drop accident.

b. Clarify whether the RWM is assumed to function in the control rod drop accident scenario evaluated at less than 10 percent power.

RAI-3

The submittal discusses a proposed compensatory measure for reactor startups without an operable RWM:

JAF will take the following compensatory measure: JAF will dedicate an independent third-party review of the rod movement sheets.

Beyond the compensatory measure described above, the site will also take the existing TS 3.3.2.1 Action C.2.2 to have a second licensed operator or other qualified member of the technical staff verify movement of control rods is in compliance with BPWS.

In addition to the above TS required action, per procedure, control rod movement for startup will take place in accordance with BWR Control Rod Movement Requirements, OP-AB-300-1001, which requires a second licensed operator to perform all Main Control Room peer checks per CEGs management model. Also, in accordance with CEGs management model, control rod movement during a startup is overseen by a dedicated Reactivity Management Senior Reactor Operator who acts to ensure all planned control rod movement is performed in accordance with approved procedures.

The licensee proposes to capture these actions in a TS Note, which would state,

• Reactor startup with the RWM inoperable is permitted while the compensatory measure described in letter JAFP-24-0047 dated September 25, 2024, is implemented.

This allowance expires on 12/31/2024 at 23:59.

a. Clarify when this independent third-party review of the rod movement sheets will take place (e.g., prior to startup, concurrent with, etc.)

b. Explain why the licensee did not propose the compensatory measures to be listed directly in the TS Note.

3