ML13186A114

Email from R. Guzman to P.Couture Request for Additional Information - Relief Request ISI-02, Application of Code Case N-716

ML13186A114
Person / Time
Site:	Vermont Yankee
Issue date:	07/05/2013
From:	Richard Guzman Plant Licensing Branch 1
To:	Couture P Entergy Nuclear Vermont Yankee
Guzman R
References
TAC MF1197
Download: ML13186A114 (1)

Text

From: Guzman, Richard Sent: Friday, July 05, 2013 11:32 AM To: 'Couture III, Philip'

Subject:

Vermont Yankee Request for Additional Information - Relief Request ISI Application of Code Case N-716 (TAC No. MF1197)

Phil, By letter dated March 27, 2013 (Agencywide Document Access and Management System Accession No. ML13092A204), Entergy Nuclear Operations, Inc. (Entergy) submitted for NRC staff review and approval Relief Request ISI-02, which requests approval of a Risk Informed Inservice Inspection (RI-ISI) program for use during the Vermont Yankee Nuclear Power Station (VY) fifth ten-year ISI interval. The program is a risk-informed, safety-based (RIS_B) program based on American society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (B&PV Code) Code Case N-716, Alternative Piping Classification and Examination,Section XI, Division 1. The NRC staff is reviewing the information provided in that letter and has determined that additional information is needed to support its review. Below is the NRC staff's request for additional information (RAI). To support the staffs timely review, we request that you provide a formal response to the RAI questions by August 15, 2013. Please contact me if you have any questions.

REQUEST FOR ADDITIONAL INFORMATION (RAI)

RELIEF REQUEST ISI-02 APPLICATION OF CODE CASE N-716 ENTERGY NUCLEAR OPERATIONS, INC.

VERMONT YAKEE NUCLEAR POWER STATION DOCKET NUMBER 50-271 (TAC NO. MF1197)

(Component Performance, NDE, and Testing Review)

1. Page 1 of the March 27, 2013 Relief Request ISI-02 states the Code of Record for the VYNPS fifth ten-year interval is the ASME Boiler and Pressure Vessel Code,Section XI, 2007 Edition, 2009 Addenda. Please clarify this, as other places in the submittal the 2007 Edition through the 2008 Addenda is referenced.

2. Both Section 3.1.4 of Enclosure 3, of the March 27, 2013, submittal and Code Case N-716 require piping within the break exclusion region greater than 4 NPS for high-energy piping systems to be assigned a high safety-significance and state that this may include Class 3 or Non-class piping. Please confirm that VY has no Class 3 or Non-class piping that met this criteria.

3. Both Section 3.1.4 of Enclosure 3, of the March 27, 2013 submittal and Code Case N-716 require any piping segment whose contribution to Core Damage Frequency is greater than 1E-06 [and in accordance with NRC feedback on previous applications 1E-07 for Large Early Release Frequency (LERF) based upon a plant-specific PSA of

pressure boundary failures] and state this may include Class 3 or Non-class piping.

Please confirm that VY has no Class 3 or Non-class piping that met this criteria.

4. Of the welds not selected for future examinations in the RIS_B program have previous examinations of any of these welds identified service induced degradation? If so what was done to mitigate the degradation mechanism.

5. The March 27, 2013 submittal states, the RIS_B Program is a living program monitored periodically for changes, where this monitoring includes numerous facets. Please confirm that vendor issued communications such as General Electric (GE)-Hitachi Safety Communications are included as part of the reviews done for the living program aspects of the program.

6. The March 27, 2013 submittal references ASME Code Case N-770-1 in several locations. N-770-1, Alternative Examinations Requirements and Acceptance Standards for Class 1 PWR Piping and Vessel Nozzle Butt Welds .. This code case is applicable to the PWSCC degradation mechanism in PWRs please describe how it will be applied to VYs RI-ISI program.

7. Section 3.3.4 of the March 27, 2013 submittal discusses Program Relief Requests and states VY will calculate coverage and use additional examinations or techniques in the same manner it has for traditional Section XI examinations. Have any of the welds selected for examination in the RIS_B been previously examined and resulted in limited examination coverage (i.e. less than 90 percent)? If so, please explain why other welds have not been selected to minimize the number of examinations with limited exam coverage.

(Probabilistic Risk Assessment Review)

8. Explain why the contribution to the core damage frequency (CDF) and large early release frequency (LERF) from adding or removing inspections to the reactor core injection cooling (RCIC) system with the break location at Class 2 Torus was not included in the change in risk evaluation. The first table in Section 3.4.1 of Relief Request ISI-02 (see pages 14 - 15) states for the Class 2 Torus break location that it includes [c]lass 2 piping connected to the Torus (ECCS pump suction) and designated as low safety significant (Lines CS-1A & 1B, RHR-2A & 2B, HPCI-4, and RCIC-3[)].

Table 3.4, Risk Impact Analysis Results, of Relief Request ISI-02 includes the contribution to CDF and LERF from the core spray (CS), residual heat removal (RHR),

and high pressure coolant injection (HPIC) systems using the Class 2 Torus (or LSS Torus as shown in Table 3.4) break location. However, the contribution to CDF and LERF from RCIC using the Class 2 Torus break location was not included in Table 3.4.

Rich Guzman Sr. Project Manager NRR/DORL/LPL1-1 US NRC 301-415-1030