DCL-06-013, Response to NRC Request for Additional Information Regarding ASME Section XI Inservice Inspection Program Relief Request NDE-SBR
| ML070780153 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 03/08/2007 |
| From: | Becker J Pacific Gas & Electric Co |
| To: | Document Control Desk, NRC/NRR/ADRO |
| References | |
| DCL-06-013, DCL-07-027, OL-DPR-80, OL-DPR-82 | |
| Download: ML070780153 (6) | |
Text
Pacific Gas and Electric Companyo James R. Becker Diablo Canyon Power Plant Vice President P. 13.
Box 566 Diablo Canyon Operations and Avila Beach, CA 93424 Station Director March 8, 2007 805.54.36 PG&E Letter DCL-07-027 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Docket No. 50-275, OL-DPR-80 Docket No. 50-323, OL-DPR-82 Diablo Canyon Units 1 and 2 Response to NRC Request for Additional Information Regard ing ASME Section XI Inservice Inspection Program Relief Request NDE-SBR
Dear Commissioners and Staff:
PG&E Letter DCL-06-013, dated March 21, 2006, submitted Relief Request, "ASME Section XI Inservice Inspection Program Relief Request NDE-SBR." The request proposes the use of an alternative to the requirements of the American Society of Mechanical Engineer Boiler and Pressure Vessel Code, Section Xl, for inservice inspection and testing of snubbers for the second 1 0-year interval of Diablo Canyon Power Plant Units 1 and 2 Inservice Inspection Program.
On December 19, 2006, the NRC staff requested additional information required to complete the review of this relief request. PG&E's responses to the staff's questions are provided in Enclosure 1.
This information does not affect the results of the technical evaluation previously transmitted in PG&E Letter DCL-06-013.
This communication contains new commitments to be implemented following NRC approval of this relief request. The commitments are contained in Enclosure 2.
If you have any questions, or require additional information, please contact Stan Ketelsen at (805) 5 720.
ýS inc rely, t( 0 ) 5 James R. Becker A member of the STARS (Strategic Teaming and Resource Sharing)
Alliance 74EoqF Catlaway
- Comanche Peak
- Diablo Canyon *Palo Verde
- South Texas Project *Wolf Creek
Document Control Desk March 8, 2007 SPage 2 PG&E Letter DCL-07-027 whyl /4279A0685022 Enclosures cc:
Edgar Bailey, DHS Terry W. Jackson Bruce S. Malleft Diablo Distribution cc/enc: Alan B. Wang A member of the STARS (Strategic Teaming and Resource Sharing)
Altiance Callaway
- Comanche Peak
- Diablo Canyon
- Palo Verde e South Texas Project *Wolf Creek PG&E Letter DCL-07-027 ENCLOSURE I Response to NRC Request for Additional Information Regarding ASME Section XI Inservice Inspection Program Relief Request NDE-SBR NRC Question 1:
In Relief Request NDE-SBR, under "Proposed Alternative and Basis for use, " the licensee states: "Additionally, the snubber and its pin-to-pin connections to the rest of the support are also included in the VT-3 examination performed in accordance with Subsection IWE." IWF-5000 requires that OM Part 4 examination be performed using VT-3 visual examination method described in IWA-22 13. Please explain whether and how the VT-3 requirements as described in IWA-2213 will be met.
PG&E Response:
IWA-2213, visual examination VT-3, is applied to all supports required to be examined by IWF-2500. Examination is required each interval per Table IWF-2500-1. All nonexempt snubbers are included in the examination schedule with their support structure whether or not they are required to be selected under IWF-251 0. When scheduled, the entire support structure from the attachment to the building structure to the pressure boundary, including the snubber itself, receives the required VT-3 examination by VT-3 certified examiners. During that inspection, the snubber and all parts described in IWF-5000(c) receive the required VT-3 examination. The VT-3 examination includes all the attributes described in paragraph 2.3.1 of OMa-1 988, Part 4. The applicable Diablo Canyon Power Plant (DCPP) procedure, Inservice Inspection (131) VT 3-1, "Visual Examination of Component and Piping Supports," includes instructions and a data sheet checklist similar to that in OMa-1 988, Part 4, Appendix A.
Snubber inspections per IWF-5000, in accordance with the frequency described in NRC Generic Letter 90-09 and Technical Specifications, are performed by snubber trained and qualified individuals who are not necessarily VT-3 qualified. Their training includes all the aspects of OMa-1 988, Part 4 and the examinations are conducted to DCPP Procedure STP M-78A, which includes a simplified checklist.
However, for consistency, applicable section(s) of ECG 99.1 will be revised to require visual examination for snubbers as stated in IWA-2213 (i.e., all inspectors will be VT-3 qualified for snubber inspection) 1 PG&E Letter DCL-07-027 NRC Question 2:
OM-4, paragraph 3.2.3.2 (b) for the 37 or 55 Testing Sample plan states that for any snubber(s) determined to be unacceptable as a result of testing, an additional sample of at least one-half the size of the initial sample lot shall be tested until total number tested is equal to the initial sample size multiplied by the factor I + C12, where C is the total number of snubbers unacceptable. Please explain whether and how this requirement, in case of 37 or 55 sample testing, will be met. (Note: SR 99. 1.3.b and SR 99. 1.3.c do not discuss additional testing).
PG&E Response:
Surveillance Requirement (SR) 99.1.3.b of Equipment Control Guideline (ECG) 99.1 discusses the 37 testing sample plan though it is not explicitly stated. It requires additional testing for snubbers determined to be unacceptable as a result of testing. It requires that as testing proceeds, the cumulative number of snubbers tested
("N") and the total number of unacceptable snubbers ("C") be plotted on Fig. 99.1-1 of ECG 99.1. This figure uses the same acceptance/rejection criteria found in Fig. C1, OM-4. The terminology in the ECG differs from that in OM-4. Applicable section(s) of ECG 99.1 will be revised to be consistent with the wording in OM-4.
SR 99.1.3.c discusses the 55 testing sample plan. It requires additional testing for snubbers determined to be unacceptable as a result of testing. It follows the same acceptability criteria as found in Paragraph 3.2.3.2 of OM-4. This includes sample expansion that is at least one-half the size of the initial sample lot, with testing continuing until the total number tested is equal to the initial sample size multiplied by the factor 1 + C/2, where C is the total number of snubbers found to be unacceptable.
The terminology in the ECG differs from that in OM-4. Applicable section(s) of ECG 99.1 will be revised to be consistent with the wording in OM-4.
It should be noted that DCPP uses the 10 percent testing sample plan for functionally testing snubbers in Units 1 and 2. The 37 and 55 testing sample plans are alternative testing plans.
NRC Question 3:
Please explain whether and [how] the requirements "Test Failure Mode Groups" as required by OM-4, paragraph 3.2.4.2 will be met by using Technical Requirement Manual [termed Equipment Control Guideline at DCPP] ECG 99. 1 and its bases.
PG&E Response:
SR 99.1.5 discusses functional test failure analysis., It requires additional functional testing of snubbers subjected to the same failure mode, same manufacturing deficiency or same design deficiency. This failure analysis meets the intent of Paragraph 3.2.4.2 of OM-4. Paragraph 3.2.4.2 is more expansive in its definition of test failure mode groups. Applicable section(s) of ECG 99.1 will be revised to be consistent with the wording in OM-4.
2 PG&E Letter DCL-07-027 NRC Question 4:
OM-4, Paragraph 1. 5.6, "Snubber Maintenance or Repair, " and 1. 5.7, "Snubber Modification and Replacement, " specifies requirements for snubber repair and replacement. The submitted relief request and the Technical Requirement Manual
[termed Equipment Control Guideline at DCPP] do not address the requirements of OM-4, Paragraphs 1. 5.6 and 1. 5.7. Please explain, whether and how these requirements will be met.
PG&E Response:
SR 99.1.6 discusses the functional testing of repaired and replaced snubbers. It requires that all replacement snubbers or snubbers which have had repairs that may affect the functional test results, be tested to meet functional test criteria prior to installation in the plant. This is consistent with Paragraph 1.5.6 of OM-4. Although not specifically stated in SR 99.1.6, all snubber maintenance/repair activities are completed per DCPP Mechanical Maintenance Procedures MP M-55.1, MP M-55.2, MP M-55.3, and MP M-55.4, and when appropriate, per the applicable vendor procedure(s). Applicable section(s) of ECG 99.1 will be revised to be consistent with the wording in OM-4.
Although not specifically stated in EGG 99.1, the DCPP design review process and written work/design procedures require that the suitability of a replacement or modified snubber for its application and operating environment be evaluated. DCPP written snubber procedures also require that replacement or modified snubbers be examined and tested. This meets the intent of Paragraph 1.5.7 of OM-4. Applicable section(s) of EGG 99.1 will be revised to be consistent with the wording in OM-4.
3 PG&E Letter DCL-07-027 ENCLOSURE 2 Commitments Commitment # 1:
Applicable section(s) of EGG 99.1 will be revised to require visual examination for snubbers as stated in IWA-2213 (i.e., all inspectors will be VT-3 qualified for snubber inspection)
Commitment # 2:
Applicable section(s) of ECG 99.1 will be revised to be consistent with the wording in OM-4.