ML18005A542

NRR E-mail Capture - Second Round of RAI for DAEC Fifth Inservice Inspection Interval Program Plan, Relief Request RR-03 - EPID: L-2017-LLR-0110

ML18005A542
Person / Time
Site:	Pilgrim
Issue date:	01/05/2018
From:	Mahesh Chawla Plant Licensing Branch III
To:	Swenzinski L Nextera Energy
References
L-2017-LLR-0110
Download: ML18005A542 (3)

Text

NRR-DMPSPEm Resource From: Chawla, Mahesh Sent: Friday, January 05, 2018 11:29 AM To: laura.swenzinski@nexteraenergy.com; Davis, J.Michael (J.Michael.Davis@nexteraenergy.com); Murrell, Bob (Bob.Murrell@nexteraenergy.com)

Cc: Kilby, Gary; Catron, Steve (Steve.Catron@fpl.com)

Subject:

Second Round of RAI for DAEC Fifth Inservice Inspection Interval Program Plan, Relief Request RR EPID: L-2017-LLR-0110 By letter dated March 7, 2017 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML17069A172), NextEra Energy Duane Arnold, LLC (NextEra, the licensee) submitted the fifth inservice inspection (ISI) interval program plan for Duane Arnold Energy Center (DAEC) for the U.S. Nuclear Regulatory Commission (NRC) review and approval. The program plan contains several relief requests from certain American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, requirements. Among them, Relief Request RR-03 proposed to use an alternative based on ASME Code Case N-702, Alternative Requirements for Boiling Water Reactor (BWR) Nozzle Inner Radius and Nozzle-to-Shell Welds, for inspection of reactor pressure vessel (RPV) nozzle inner radius and nozzle-to-shell welds at DAEC.

Background

On October 26, 2017 (ADAMS Accession No. ML17300A195), the licensee provided response to the NRC staffs request for additional information (RAI), sent via an email dated August 8, 2017 (ADAMS Accession No. ML17220A333). The NRC staff reviewed the RAI response and determined that additional information was required to complete the response. On November 7, 2017, a teleconference was held between the NRC staff and the NextEra representatives to discuss the needed information. As a result, on December 7, 2017 (ADAMS Accession No. ML17341A852), the licensee provided supplemental response to the original RAI. The NRC staff has reviewed this supplemental response and found four issues with the licensees supplemental response:

• The response states that there are no acceptance criteria for probability of failure (PoF) due to normal operation. The NRC staff noted that the acceptance criteria for PoF due to normal operation was established in the safety evaluation (SE) for the Boiling Water Reactor Vessel Internals Project (BWRVIP) report, BWRVIP-108, Technical Basis for the Reduction of Inspection Requirements for the Boiling Water Reactor Nozzle-to-Vessel Shell Welds and Nozzle Blend Radii, (ADAMS Accession No. ML073600374).

• The response states that linear elastic fracture mechanics (LEFM) is overly conservative for vessel material behavior at normal operating temperatures, and the number reported in the BWRVIP-108 SE for normal operation PoF was used for comparative purposes only. The NRC staff noted that normal operation includes heatup, cooldown, and hydro/pressure test, covering the entire temperature range.

Therefore, using LEFM is appropriate. Further, the supplemental response by Boiling Water Reactor Vessel Internals Project (BWRVIP) in letter dated September 13, 2007 (ML072600167) to support BWRVIP-108 contains PoF values for both the normal operating condition and the low-temperature overpressure (LTOP) condition for all simulation cases without emphasizing one condition. Therefore, during the BWRVIP-108 review, the BWRVIP and the NRC treated both normal operation condition and LTOP condition equally.

• The response states that the PoF due to normal operation is irrelevant because when the plant stays within the required pressure-temperature (P-T) curve limits the regulatory required margin to failure is met. The NRC staff noted that the P-T limit or pressurized thermal shock (PTS) requirements are completely separated from the ASME inspection requirements. A plant meeting the P-T limit (BWRs and PWRs) or PTS (PWRs) requirements still needs to perform ASME Code required inspections. The 1

inspection alternative proposed in BWRVIP-108 was based on the probabilistic fracture mechanics (PFM) results for the normal and LTOP conditions. Therefore, the PoF due to normal operation is essential information for the NRC staffs evaluation.

• The response implied that conditional PoF is more relevant in this evaluation. In the risk evaluation, the NRC staff always considers the event frequency and the conditional PoF. If the event frequency is zero, then the value of conditional PoF is meaningless. Both were considered by the BWRVIP and the NRC staff during the BWRVIP-108 review.

Hence, the NRC staff determined that the following follow-up RAI is needed to complete the review of RR-03.

Follow-up RAI The licensees October 26, 2017, response to the RAI contains a plant-specific PFM for the LTOP condition to support Relief Request RR-03. However, the PFM results in the supplemental response by Boiling Water Reactor Vessel Internals Project (BWRVIP) in letter dated September 13, 2007 (ML072600167) to support BWRVIP-108, indicated that the PFM results for normal operation are more limiting than the LTOP condition.

Since the approval of BWRVIP-108 was based on the BWRVIPs PFM results, which indicated that both the normal condition and the LTOP condition satisfy the NRCs safety goal of 5x10-6, performing PFM results for the normal condition is essential. Please provide the PFM results for the normal condition, or quantitative information to demonstrate that the normal condition is not limiting for DAEC.

Please arrange a teleconference with the NRC staff to discuss the above information. Thanks Mahesh Chawla Project Manager Division of Operating Reactor Licensing (DORL)

Branch III (301) 415-8371 2

Hearing Identifier: NRR_DMPS Email Number: 80 Mail Envelope Properties (MW2PR0901MB2442B41210DA964B218B78F3F11C0)

Subject:

Second Round of RAI for DAEC Fifth Inservice Inspection Interval Program Plan, Relief Request RR EPID: L-2017-LLR-0110 Sent Date: 1/5/2018 11:29:10 AM Received Date: 1/5/2018 11:29:00 AM From: Chawla, Mahesh Created By: Mahesh.Chawla@nrc.gov Recipients:

"Kilby, Gary" <Gary.Kilby@fpl.com>

Tracking Status: None "Catron, Steve (Steve.Catron@fpl.com)" <Steve.Catron@fpl.com>

Tracking Status: None "laura.swenzinski@nexteraenergy.com" <laura.swenzinski@nexteraenergy.com>

Tracking Status: None "Davis, J.Michael (J.Michael.Davis@nexteraenergy.com)" <J.Michael.Davis@nexteraenergy.com>

Tracking Status: None "Murrell, Bob (Bob.Murrell@nexteraenergy.com)" <Bob.Murrell@nexteraenergy.com>

Tracking Status: None Post Office: MW2PR0901MB2442.namprd09.prod.outlook.com Files Size Date & Time MESSAGE 5258 1/5/2018 11:29:00 AM Options Priority: Standard Return Notification: No Reply Requested: No Sensitivity: Normal Expiration Date:

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