ML20272A011

Request for Additional Information - Palisades Relief Request RR 5-8 (Proposed Alternative) for Reactor Pressure Vessel Head Penetration Repairs

ML20272A011
Person / Time
Site:	Palisades
Issue date:	09/26/2020
From:	Booma Venkataraman Plant Licensing Branch III
To:	Miksa J Entergy Nuclear Operations
Venkataraman B
References
EPID L-2020-LLR-0128
Download: ML20272A011 (2)

Text

From: Venkataraman, Booma To: MIKSA, JAMES P Cc: Salgado, Nancy

Subject:

REQUEST FOR ADDITIONAL INFORMATION: Palisades Relief Request RR 5-8 (Proposed Alternative) for Reactor Pressure Vessel Head Penetration Repairs (EPID: L-2020-LLR-0128)

Date: Saturday, September 26, 2020 3:17:00 PM Attachments: Palisades_Relief Request_5-8_ RAI-FINAL_09262020.docx Mr. Miksa, By letter dated September 23, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20267A386), Entergy Nuclear Operations Inc. (Entergy) submitted a relief request, RR 5-8, pursuant to Title 10 of the Code of Federal Regulations 50.55a (z)(1), for a proposed alternative to certain requirements of American Society of Mechanical Engineers (ASME) Code for repair of reactor pressure vessel head penetrations, on the basis of acceptable level of quality and safety for the Palisades Nuclear Plant.

A draft request for information (RAI) was sent to you on September 25, 2020. A clarification call was conducted on September 25, 2020, between NRC staff and Entergy. The final RAI version is attached to this e-mail. Further to the clarification call, Entergy indicated that it planned to respond to the attached RAI with a supplement by September 28, 2020.

Please treat this e-mail as transmittal of formal RAIs. If circumstances result in the need to revise the requested response date, please contact me at (301) 415-2934, or via email at Booma.Venkataraman@nrc.gov.

Sincerely, Booma Booma Venkataraman Project Manager, NRR/DORL/LPL3 Office of Nuclear Reactor Regulation Booma.Venkataraman@nrc.gov 301.415.2934

REQUEST FOR ADDITIONAL INFORMATION PROPOSED ALTERNATIVE TO ASME SECTION XI CODE REQUIREMENTS REACTOR PRESSURE VESSEL HEAD PENETRATION REPAIRS ENTERGY NUCLEAR OPERATIONS, INC PALISADES NUCLEAR PLANT DOCKET NOS. 50-255 By letter dated September 23, 2020 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML20267A386), Entergy Nuclear Operations Inc. (Entergy, the licensee) submitted a relief request, RR 5-8, pursuant to Title 10 of the Code of Federal Regulations (10 CFR) 50.55a (z)(1), for a proposed alternative to certain requirements of American Society of Mechanical Engineers (ASME) Code for repair of reactor pressure vessel (RPV) head penetrations, on the basis of acceptable level of quality and safety for Palisades Nuclear Plant (Palisades).

The NRC staff has reviewed the submittal and determined that additional information is needed to complete its review.

Background and Regulatory Basis Considering the lack of surface stress improvement in the repaired region, and the limited duration of the proposed alternative, the staff is performing independent confirmatory flaw evaluations. To conduct these flaw evaluations the staff requires additional information as to the residual and operating stresses in the Alloy 600 penetration tube and the water chemistry near the repaired surfaces. This will allow the staff to verify the flaw evaluation summarized in the submittal and that the proposed duration for the alternative is appropriate.

The requested information will allow the staff to determine if the repair method and duration of the proposed alternative provide an acceptable level of quality and safety.

RAI-1

1) Provide following information associated with the flaw analysis of two limiting conditions of the repaired alloy 600 nozzle in the reactor coolant pressure boundary;

a. The highest weld residual plus operating stress through-wall profile of the alloy 600 nozzle adjacent to the Alloy 52 weld.

b. The highest weld residual plus operating stress through-wall profile of the roll-expanded region of the repaired Alloy 600 nozzle.

c. The estimated crack growth rate for the roll-expanded region of the repaired Alloy 600 nozzle.

2) Provide the hydrogen concentration expected during the next cycle of operation at Palisades in the upper head region next to the repaired remaining Alloy 600 nozzle.