ML18214A281

Request for Additional Information Draft - Relief Request I5R-02 (EPID L-2018-LLR-0055)

ML18214A281
Person / Time
Site:	Peach Bottom
Issue date:	08/02/2018
From:	Tobin J C Plant Licensing Branch 1
To:	David Helker Exelon Nuclear
Tobin J C
References
EPID L-2018-LLR-0055
Download: ML18214A281 (3)

Text

From: Tobin, Jennifer To: Helker, David P:(GenCo-Nuc)

Cc: "Gropp Jr, Richard W:(GenCo-Nuc)"

Subject:

Peach Bottom Units 2 and 3 - Request for Additional Information DRAFT - Relief Request I5R-02 (EPID L-2018-LLR-0055)Date: Tuesday, July 31, 2018 12:47:00 PM

Dear Mr. Helker,

By letter dated April 19, 2018 (Accession No. ML18109A116), Exelon Generation Company, LLC requested relief from the requirement in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2013 Edition, paragraph IWE-1232(a) inspection requirements for penetration N-3 (construction manhole) in the drywells of Peach Bottom Units 2 and 3.

The Nuclear Regulatory Commission's (NRC) staff is reviewing your submittal and has determined that additional information is needed to complete its review.

The specific request for additional information (RAI) questions are provided below.

These DRAFT questions are being sent to ensure that the questions are understandable, the regulatory basis for the questions is clear, and to determine if the information was previously docketed. A clarification phone call to discuss the DRAFT RAIs will be scheduled, if needed. If you have any questions, please contact me at (301) 415-2328.

A copy of this e-mail will be made publicly available in ADAMS.

Thanks, Jenny Jenny Tobin Project Manager NRR/DORL/LPL-1 Office O9-C12 Phone 301-415-2328 REQUEST FOR ADDITIONAL INFORMATION (DRAFT)

BY THE OFFICE OF NUCLEAR REACTOR REGULATION PROPOSED ALTERNATIVE NO.

I5R-02 FIFTH 10-YEAR INTERVAL INSERVICE INSPECTIONS EXELON GENERATION COMPANY, LLC PEACH BOTTOM ATOMIC POWER STATION, UNITS 2 AND 3 DOCKET NOS. 50-277 AND 50-278 EPID: L-2018-LLR-0055

Background

By letter dated April 19, 2018, Exelon Generation Company, LLC, (the licensee) submitted relief request I5R-02 associated with the third Containment Inservice Inspection (CISI) interval for Peach Bottom Atomic Power Station, Units 2 and 3.

Relief Request I5R-02 requests relief from the requirement in the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code,Section XI, 2013 Edition, paragraph IWE-1232(a) inspection requirements for penetration N-3 (construction manhole) in the drywells of Peach Bottom Units 2 and 3.

The licensee is requesting this relief pursuant to 10 CFR 50.55a(z)(2).

The licensee stated that compliance with IWE

-1232(a) requirements addressing examination of inaccessible surface areas of Class MC containment vessels, parts and appurtenances embedded in concrete or otherwise made inaccessible as a result of construction, repair, or replacement activities would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety.

The licensee also stated that IWE-1232(a) ASME Code requirements would involve excavation and demolition of the concrete around the bottom head of the drywell and potentially additional drywell floor concrete removal.

Instead of performing the required IWE examination of penetration N-3 the licensee proposed alternative is to perform Integrated Leak Rate Tests (ILRT) in accordance with its Appendix J Program.

Issue: The Nuclear Regulatory Commission (NRC or the staff) reviewed Relief Request I5R-02 proposed alternative in lieu of the IWE-1232(a) ASME Code requirements and determined that in order to complete its evaluation it needs to assess whether the proposed alternative provides reasonable assurance of structural integrity of the inaccessible surface areas of the Class MC vessel (drywell shell).

The staff noted that the last docketed information available on the condition of the drywell shell surface areas and moisture barriers was provided by letter dated April 13, 2015 (ADAMS Accession Number ML15104A361) in a response to requests for additional information regarding a license amendment request to extend Type A and Type C Leak Rate Test Frequencies.

The staff needs additional information regarding any degradation of the inaccessible surface areas of the drywell and drywell moisture barriers found since April 13, 2015, that could impact the structural integrity of the drywell shells at Peach Bottom Units 2 and 3.

In addition the staff noted that portions of the below grade concrete adjacent to penetration N-3 may be exposed to an aggressive environment that could affect the intended function of the drywell shell.

Request: a. Provide a summary of IWE inspection results (since April 2015) associated with degraded conditions of accessible surface areas of the Peach Bottom Units 2 and 3 drywells and any corrective actions taken to disposition the findings.

b. Provide information of instances (since April 2015), during implementation of the Peach Bottom Units 2 and 3 CISI programs, where existence of or potential for degraded conditions in inaccessible areas were identified and evaluated based on conditions found in accessible areas, as required by 10 CFR 50.55a(b)(2)(ix)(A).

Discuss the findings and corrective actions taken to disposition the findings.

c. Provide operating experience (since April 2015) relative to the inspection of the drywell internal moisture barriers at the juncture of the drywell shell and the concrete floor or in any other floor locations for Peach Bottom Units 2 and 3.

Also provide operating experience related to any evidence of potential moisture intrusion associated with aggressive groundwater on inaccessible areas of the drywell shell.

d. Identify potential below grade aggressive environments (e.g., groundwater, sulfates, and chlorides) that could result in degradation of Peach Bottom Units 2 and 3 penetration N-3 and adversely affect the intended function of the drywell shell. If such environment exists discuss steps taken to provide reasonable assurance of the continued intended functionality of the drywell shell for the duration of this relief request.