ML091870051
| ML091870051 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 07/15/2009 |
| From: | Pickett D Plant Licensing Branch 1 |
| To: | John Carlin Ginna |
| Pickett D | |
| References | |
| TAC ME1364 | |
| Download: ML091870051 (4) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555*0001 July 15, '2JrfJ Mr. John 1. Carlin Vice President RE. Ginna Nuclear Power Plant RE. Ginna Nuclear Power Plant, LLC 1503 Lake Road Ontario, NY 14519
SUBJECT:
REQUEST FOR ADDITIONAL INFORMATION RE: FOURTH INTERVAL INSERVICE INSPECTION PROGRAM RELIEF REQUEST NO. 24 (TAC NO. ME1364)
Dear Mr. Carlin:
By letter dated May 22,2009, RE. Ginna Nuclear Power Plant, LCC submitted Relief Request No. 24 for the Fourth Interval Inservice Inspection Plan. The relief request proposes an alternative, pursuant to Title 10 of the Code of Federal Regulations, Section 50.55a(a)(3)(i), to the requirement to perform bare metal inspections of the reactor vessel bottom mounted penetrations.
The Nuclear Regulatory Commission staff has reviewed the information provided and has determined that additional information is needed to complete its review. Enclosed is the staff's request for additional information (RAI). As discussed with your staff, we understand that you intend to respond to this RAI by approximately August 14, 2009.
Please contact me at 301-415-1364 if you have any questions.
Sincerely, Douglas V. Pickett, Senior Project Manager Plant Licensing Branch 1-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket No. 50-244
Enclosure:
As stated cc w/encl: Distribution via Listserv
REQUEST FOR ADDITIONAL INFORMATION FOURTH INTERVAL INSERVICE INSPECTION PROGAM RELIEF REQUEST NO. 24 RE. GINNA NUCLEAR POWER PLANT DOCKET NO. 50-244 Recently, the NRC invoked the inspection requirements of American Society of Mechanical Engineers Code Case N-722, "Additional Examinations for PWR [pressurized-water reactor]
Pressure Retaining Welds in Class 1 Components Fabricated With Alloy 600/82/182,Section XI, Division 1," via the incorporation of Title 10 of the Code of Federal Regulations, Section 50.55a(g)(6)(E). As a result, PWR licensees are required to perform a 100 percent bare metal vessel inspection of their unit's reactor pressure vessel (RPV) bottom mounted instrumentation (8MI) nozzles during every other refueling outage (RFO) beginning with the unit's first RFO after January 1J 2009. This would include the Ginna RFO scheduled for the fall 2009.
One objective of the bare metal visual inspections is to detect leakage of reactor coolant through primary water stress-corrosion cracking (PWSCC) of the nozzle alloy 600 base material or alloy 82/182 J-groove weld material before the leaked coolant causes consequential damage.
Potential consequential damage includes 1) corrosion of the RPV alloy steel base material and
- 2) PWSCC of the alloy 600 nozzle base material from the outside diameter (00) of the nozzle.
Such cracking has been observed in RPV upper head penetrations to be circumferential in orientation which creates the possibility of nozzle ejection.
At Ginna, for some 8MI nozzles, a paint or coating has wicked up into and sealed and occluded the annular gap between the alloy 600 nozzle and the alloy steel base material. It is possible that the paint or coating could prevent egress of the leaked coolant from the annular gap, which could facilitate the initiation and growth of 00 circumferential cracking and inhibit the ability to detect leakage via visual examination. To address this, the licensee has proposed to perform a best effort visual inspection of all RE. Ginna, Unit 1 8MI nozzles during the unit's 2009 RFO and volumetric (ultrasonic) examinations of all RE. Ginna, Unit 1 8MI nozzles during the unit's scheduled 2011 RFO.
Regarding the 2009 visual examination of occluded 8MI nozzles:
- 1. Provide a discussion of how visual examination or leak detection provides a basis for ensuring circumferential PWSCC is not occurring on the 00 of the alloy 600 nozzles if the annulus is plugged and occluded by paint.
- 2. Provide copies and a discussion of any qualification or simulation testing that supports your conclusion that "the paint is unlikely to retain a leak." This should include: a discussion of any actual shear strength or adhesion strength test data available for the painUcoating on the bottom of the RE. Ginna, Unit 1 RPV; copies of the original Enclosure
- 2 paint/coating specification, application procedures and qualification report, as necessary to demonstrate the materials characteristics of the paint/coating; and, an assessment of the load which would be placed on the coating by leakage into the annular region.
- 3. Provide a timeline and description of the qualification of ultrasonic test equipment that will be used during the volumetric examination of the nozzles proposed for the 2011 RFO. Include a description of the probes and mockups and the dates that the mockups and probes were, or will be, procured. This information is necessary for the staff to assess the status of qualification activities to date. If no qualification activities have yet been completed, please identify what kind of administrative actions have been put in place to ensure that you will not discover, during the qualification activities, any impediments to volumetric inspection that would necessitate any additional submittals requesting delay, deferral orrelief from the commitment to complete the volumetric examination.
- 4. Discuss how the 2011 volumetric examination of the volume of the nozzle alloy 600 base material, as detailed in Figure 1 of your submittal, will ensure that PWSCC through the J-groove weld has not resulted in leakage of reactor coolant into the annular region between the alloy 600 nozzle and the alloy steel RPV bottom head for those nozzles that have paint/coating plugging and occluding the outer portion of the annulus.
- 5. Discuss any additional operator training that may be implemented regarding operator response to 8MI failure scenarios for the interim period from now until the volumetric examinations of all R.E. Ginna 8MI nozzles will be completed in 2011.
ML091870051 OFFICE PM/LPL 1-1 LA:LPL 1-1 BC/CVIB BC/LPL 1-1 NAME DPickett SLittie MMitchell NSalgado DATE 07/13/09 07 /13/ 09 07/14/09 07/15/09