ML13074A818

Diablo Canyon, Units 1 and 2, Request for Additional Information Email, Relief Request RVFLNG-INT3 - Alternative to ASME Code Pressure Test Requirements for Class 1 Reactor Vessel Flange Leakoff Lines, Third 10-Year Inservice Inspection Int

ML13074A818
Person / Time
Site:	Diablo Canyon
Issue date:	03/15/2013
From:	Polickoski J T Plant Licensing Branch IV
To:	Soenen P R Pacific Gas & Electric Co
References
TAC MF0408, TAC MF0409
Download: ML13074A818 (2)

Text

From:Polickoski, JamesTo:Soenen, Philippe RCc:Lent, Susan; Baldwin, Thomas (DCPP); Burkhardt, JanetSubject:RAI: Request for Additional Information in regards to Diablo Canyon Power Plant Relief Request RVFLNG-INT3 -U1 & U2 (TAC Nos. MF0408 and MF0409)Date:Friday, March 15, 2013 3:26:39 PMMr. Soenen, By letter dated December 20, 2012 (Agencywide Documents Access and ManagementSystem (ADAMS) Accession Number ML12356A059), Pacific Gas and Electric Company (the licensee) requested relief from the requirements of the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code),Section XI, Table IWB-2500-1 and Paragraph IWB-5222 at Diablo Canyon Power Plant (DCPP) Units 1 and 2. The licensee proposed to use the alternative, "Request Number RVFLNG-INT3 - U1 &U2," to the ASME Code,Section XI, pressure test requirements for inservice inspection (lSI) of Class 1 reactor vessel flange head leakoff lines for DCPP Units 1 and 2. Based on a review of the submittal, the NRC staff has determined that the followingadditional information is required in order to complete its review. The request for additionalinformation was discussed with Mr. Soenen on March 15, 2013. It was agreed that aresponse to these RAIs would be provided by May 3, 2013. Should the NRC determinethat this RAI is no longer necessary prior to the scheduled date, the request will be withdrawn. If circumstances result in the need to revise the requested response date,please contact me at (301) 415-5430 or via e-mail at james.polickoski@nrc.gov. The NRC staff has determined that no security-related or proprietary information is contained herein. Sincerely, Jim Polickoski James T. PolickoskiProject Manager, Diablo Canyon Power Plant US NRC/NRR/DORL/LPL4 james.polickoski@nrc.gov301-415-5430 REQUEST FOR ADDITIONAL INFORMATIONREQUEST NUMBER RVFLNG-INT3 - U1 & U2PRESSURE TEST OF REACTOR VESSEL HEAD FLANGE LEAKOFF LINESDIABLO CANYON POWER PLANT UNITS 1 AND 2PACIFIC GAS AND ELECTRIC COMPANYDOCKET NUMBERS 50-275 AND 50-323(TAC NOS. MF0408 AND MF0409) To complete its review, the NRC staff requests the following additional information: 1. Provide the following in regards to piping and configuration:(1) Submit a piping and instrumentation diagram (P&ID) for the entire reactorvessel head flange leakoff system.

(2) Identify on the P&ID the pipe segments that are required to be examined in accordance with the ASME Code,Section XI, Table IWB-2500-1, ExaminationCategory B-P and Item Number B15.10.(3) Identify on the P&ID the pipe segments that are accessible and inaccessible forinspection. 2. Provide the following in regards to leakage visual examination:(1) For the accessible portion of the subject piping, describe exactly how the visualexamination will be performed to identify the pipe through-wall leakage.

(2) If the pipe is insulated, discuss whether the insulation will be removed. Ifinsulation will not be removed, discuss how the pipe would be examined to identify the potential pipe through-wall leakage.

(3) If the subject pipe is located in a high elevation or far away location from theexaminer, describe how the potential pipe through-wall leakage can be identified.

(4) Discuss how the operator distinguishes a pipe through-wall leakage fromvarious other leakage sources (e.g., bolted joint [flange] leakage, valve in-line leakage, and leakoff through the O-ring, etc.). 3. Provide the following:(1) For the pipe segments that are inaccessible for inspection, discuss how thestructural integrity of the inaccessible pipe segments will be demonstrated.

(2) Discuss the degradation history of the subject piping (e.g., wall thinning,cracking, etc.).

(3) Provide the material specification of the affected piping and associated welds.(4) Provide the design pressure and wall thickness of the leakoff lines. 4. Provide the following related to normal operation:(1) Describe the system alignment and configuration of the leakoff lines duringnormal operation (e.g., valve positions, alarm setpoints, etc.). Pictorialrepresentations via the above requested P&IDs may be helpful.

(2) When leakage is detected via high temperature alarm initiation, discuss theprocedures in response to that leakage in the O-ring leakoff line (e.g., describe the actions that would be taken after the alarm is initiated).

(3) If the leakoff line itself was degraded (leaking) and diverting leakoff, discusshow it would be determined if the leakoff line itself was leaking, once the above alarm actuated.