ML100540220
| ML100540220 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 02/19/2010 |
| From: | Price J Dominion Nuclear Connecticut |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 09-759A, IR-3-01, FOIA/PA-2011-0115 | |
| Download: ML100540220 (4) | |
Text
February 19, 2010 t)ODllOion Nuclear Connecticut, Inc.
111111 Dominion Boulevard, Glen Allen, Virgml.l ) Ii '(,0
- f
\\ddress: www.dom.col1l U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Serial No.
NSSLIWDC Docket No.
License No.
09-759A RO 50-423 NPF-49 DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3 RELIEF REQUEST IR-3-01 SUPPLEMENTAL INFORMATION REGARDING SNUBBER INSPECTION AND TESTING FOR THIRD 10-YEAR INTERVAL As a part of the inservice inspection (lSI) program, Dominion Nuclear Connecticut, Inc.
(DNC) submitted a letter dated April 28, 2009 requesting approval to use alternative examination and testing requirements for Code Class 1, 2, 3, and MC snubbers at Millstone Power Station Unit 3
(MPS3).
The April 28,
- 2009, letter requested authorization to apply the visual and functional testing requirements that are prescribed by MPS3 Technical Specification 4.7.10 (including sampling and frequency requirements) as an alternative to performing inservice examination and testing in accordance with ASME/ANSI OM, Part 4, as required by IWF-5300, in Subsection IWF of the 2004 Edition of Section XI.
In a letter dated December 1, 2009, the NRC transmitted a request for additional information (RAI).
In a letter dated December 1, 2009, DNC submitted a response to this RAI.
The purpose of this letter is to provide an updated response to NRC question 4 in DNC letter dated December 1, 2009. The updated response provides additional details regarding the similarity of Technical Specification Figure 4.7-1 to Figure 7.14.1-1, of subsection "Inservice Testing of Dynamic Restraints (Snubbers) (ISTD)" of ASME OM Code-1995 edition. Attachment 1 provides DNC's updated response to question 4.
If you should have any questions regarding this submittal, please contact Wanda Craft at (804) 273-4687.
Sincerely,
)
~
~
L---
J. J~aln rice Vi~)r sident - Nuclear Engineering Attachments:
- 1. Relief Request IR-3-01 Updated Response to Question 4 of Request for Additional Information Regarding Snubber Inspection and Testing for Third 10-Year Interval
Serial No. 09-759A Docket No. 50-423 Response to RAI on Snubber Inspection and Testing Page 2 of 2 Commitments made in this letter:
- 1. None cc:
U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406-1415 Ms. C. J. Sanders NRC Project Manager, Mail Stop 883 U.S. Nuclear Regulatory Commission One White Flint North 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
Serial No. 09-759A Docket No. 50-423 ATTACHMENT 1 RELIEF REQUEST IR-3-01 UPDATED RESPONSE TO QUESTION 4 of REQUEST FOR ADDITIONAL INFORMATION REGARDING SNUBBER INSPECTION AND TESTING FOR THIRD 10-YEAR INTERVAL DOMINION NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNIT 3
Serial No. 09-759A Docket No. 50-423 Response to RAI on Snubber Inspection and Testing, Page 1 of 1 By letter dated April 28, 2009 (Agencywide Document Access and Management System Accession (ADAMS) No. ML091310666), Dominion Nuclear Connecticut, Inc. (DNC) submitted Relief Request IR-3-01 for Millstone Power Station, Unit No.3 (MPS3). The April 2:8, 2009, letter requested authorization of the proposed alternative examination and testing requirements for Code Class 1, 2, 3, and MC snubbers. In a letter dated December 1, 2009, the NRC transmitted a request for additional information (RAI). In a letter dated December 1, 2009, DNC submitted a response to this RAI. The following is an updated response to NRC question 4:
NRC <:lUESTION 4:
PleasE~ explain how snubber functional test in accordance with MPS3 TS Figure 4.7-1 as specified in TS SR 4.7.1 0.e(2) meets the functional test requirements of the "37 testin~l sample plan" Figure C1 of Appendix C of the OMa-1988.
DNC UPDATED RESPONSE:
The sample plan using TS Figure 4.7-1 is consistent with the 37 testing sample plan using Figure C1 of Appendix C of the OMa-1988 addenda. In TS Figure 4.7-1, the accept line is shown with the equation of C =0.055N - 2.007. "C" is the number of snubbers found which do not meet the functional test acceptance criteria and "N" is the cumulative number of a type tested. Solving for N, the equation becomes N = 36.49 +
18.18C, which is used in newer versions of the OM code. This provides the statistical basis to establish a 95% confidence that 90% of the group's snubbers are operable.
TS Fi~lure 4.7-1, however, does not include a reject criterion, although the 1987 edition 88 addenda of the OM Part 4 includes a reject criterion for the 37 plan. According to the OM plan, if at any point in the course of the testing, the number of snubbers found not to meet the functional test acceptance criteria exceeds the quantity (0.055N + 2.007),
where N is equal to the total number of snubbers tested, the entire population must be rejected. The reject criterion was removed in newer versions of the OM code.
MPS3 Technical Specification (TS) Figure 4.7-1 is very similar to Figure ISTD 7.14.1-1, "The ~17 Testing Sample Plan" of subsection Inservice Testing of Dynamic Restraints (Snubbers) (ISTD) of the ASME OM Code -1995 edition. The ASME OM Code -1995 edition was incorporated by reference into CFR 50.55a (b)(3)(v). Therefore, the use of the sample plan in TS Figure 4.7-1 is consistent with Figure ISTD 7.14.1-1, subsection ISTD of the ASME OM Code -1995 edition as incorporated by reference into CFR 50.55a (b)(3)(v).