ML032690641
| ML032690641 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 10/14/2003 |
| From: | Holden C NRC/NRR/DLPM/LPD1 |
| To: | Christian D Dominion Nuclear Connecticut |
| References | |
| EA-03-009, TAC MC0619 | |
| Download: ML032690641 (10) | |
Text
October 14, 2003 Mr. David A. Christian Sr. Vice President and Chief Nuclear Officer Dominion Nuclear Connecticut, Inc.
Innsbrook Technical Center 5000 Dominion Boulevard Glen Allen, VA 23060-6711
SUBJECT:
RELAXATION OF THE REQUIREMENTS OF ORDER EA-03-009 REGARDING REACTOR PRESSURE VESSEL HEAD INSPECTIONS, MILLSTONE POWER STATION, UNIT NO. 2 (TAC NO. MC0619)
Dear Mr. Christian:
On February 11, 2003, the U.S. Nuclear Regulatory Commission (NRC) issued Order EA-03-009 requiring specific inspections of the reactor pressure vessel (RPV) head and associated penetration nozzles at pressurized water reactors. The NRC issued an errata to the Order on March 14, 2003, to correct an administrative part of the Order related to requests for relaxation of the Order requirements.Section IV.F of the Order states that requests for relaxation associated with specific penetration nozzles will be evaluated by the NRC staff using its procedure for evaluating proposed alternatives to the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) in accordance with Section 50.55a(a)(3) of Title 10 of the Code of Federal Regulations (10 CFR 50.55a(a)(3)).
Sections IV.A and IV.B of the Order provide criteria to categorize each plants RPV head with respect to its susceptibility to primary water stress corrosion cracking (PWSCC). For plants such as Millstone Power Station, Unit No. 2 (MP2), with RPV heads that are categorized as being highly susceptible to PWSCC,Section IV.C(1)(b) of the Order requires that the RPV head penetration nozzles be inspected each refueling outage using either of the following techniques:
(1) ultrasonic testing (UT) from two inches above the J-groove weld to the bottom of the nozzle and an assessment to determine if leakage has occurred in the interference fit zone, or (2) eddy current testing or dye penetrant testing (PT) of the wetted surface of each J-groove weld and nozzle base material to at least two inches above the J-groove weld.
By letter dated September 3, 2003, Dominion Nuclear Connecticut, Inc. (DNC) requested relaxation from the requirements in Section IV.C(1)(b) of the Order for MP2. The relaxation request was made pursuant to the procedure specified in Section IV.F of the Order.
Specifically, for inspection of the RPV head vent line penetration nozzle, DNC requested authorization to use a combination of UT on the nozzle base material, and PT on the nozzle J-groove weld.
The NRC staff has reviewed and evaluated the information provided in support of your request for relaxation as documented in the enclosed Safety Evaluation (SE). The staffs SE concludes that DNC has demonstrated good cause for the requested relaxation and that the proposed alternative provides an acceptable level of quality and safety. Therefore, pursuant to Section IV.F of the Order, and 10 CFR 50.55a(a)(3), the NRC staff authorizes the proposed relaxation and alternative inspection of the RPV head vent line penetration nozzle at MP2 during the period while NRC Order EA-03-009 remains in effect.
D. Christian Be aware that when vessel head inspections are performed using ASME Code requirements, acceptance criteria, or qualified personnel, those activities and all related activities fall within the jurisdiction of the ASME Code. Therefore, Order-related inspection activities may be subject to third party review, including those by the Authorized Nuclear Inservice Inspector.
The NRC staff considers that the non-timely submittal of your request (September 3, 2003, with a licensee need date of October 15, 2003) created an unacceptable short staff review time and did not contribute toward the NRCs goal of efficient and effective use of staff resources. This issue was discussed with Mr. David Dodson of your staff.
Sincerely,
/RA/
Cornelius F. Holden, Director Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-336
Enclosure:
Safety Evaluation cc w/encl: See next page
D. Christian Be aware that when vessel head inspections are performed using ASME Code requirements, acceptance criteria, or qualified personnel, those activities and all related activities fall within the jurisdiction of the ASME Code. Therefore, Order-related inspection activities may be subject to third party review, including those by the Authorized Nuclear Inservice Inspector.
The NRC staff considers that the non-timely submittal of your request (September 3, 2003, with a licensee need date of October 15, 2003) created an unacceptable short staff review time and did not contribute toward the NRCs goal of efficient and effective use of staff resources. This issue was discussed with Mr. David Dodson of your staff.
Sincerely,
/RA/
Cornelius F. Holden, Director Project Directorate I Division of Licensing Project Management Office of Nuclear Reactor Regulation Docket No. 50-336
Enclosure:
Safety Evaluation cc w/encl: See next page DISTRIBUTION:
PUBLIC CRaynor OGC SBloom PDI-2 Reading REnnis ACRS RPulsifer CHolden TChan GHill (2) BMcDermott, RGN-I JClifford ZFu JJolicoeur ADAMS Accession Number: ML032690641 OFFICE PDI-2/PM PDI-2/LA EMCB/SC OGC PDI-2/SC PDI/D NAME REnnis CRaynor TChan MYoung VNerses for JClifford CHolden DATE 10/03/03 10/03/03 10/03/03 10/10/03 10/14/03 10/14/03 OFFICIAL RECORD COPY
Millstone Power Station, Unit No. 2 cc:
Lillian M. Cuoco, Esquire Mr. J. Alan Price Senior Counsel Site Vice President Dominion Resources Services, Inc. Dominion Nuclear Connecticut, Inc.
Rope Ferry Road Rope Ferry Road Waterford, CT 06385 Waterford, CT 06385 Edward L. Wilds, Jr., Ph.D. Mr. John Markowicz Director, Division of Radiation Co-Chair Department of Environmental Protection Nuclear Energy Advisory Council 79 Elm Street 9 Susan Terrace Hartford, CT 06106-5127 Waterford, CT 06385 Regional Administrator, Region I Mr. Evan W. Woollacott U.S. Nuclear Regulatory Commission Co-Chair 475 Allendale Road Nuclear Energy Advisory Council King of Prussia, PA 19406 128 Terrys Plain Road Simsbury, CT 06070 First Selectmen Town of Waterford Ms. Nancy Burton 15 Rope Ferry Road 147 Cross Highway Waterford, CT 06385 Redding Ridge, CT 00870 Charles Brinkman, Director Mr. G. D. Hicks Washington Operations Nuclear Services Director - Nuclear Station Safety and Licensing Westinghouse Electric Company Dominion Nuclear Connecticut, Inc.
12300 Twinbrook Pkwy, Suite 330 Rope Ferry Road Rockville, MD 20852 Waterford, CT 06385 Senior Resident Inspector Mr. S. E. Scace Millstone Power Station Assistant to the Site Vice President c/o U.S. Nuclear Regulatory Commission Dominion Nuclear Connecticut, Inc.
P.O. Box 513 Rope Ferry Road Niantic, CT 06357 Waterford, CT 06385 Mr. W. R. Matthews Mr. Chris L. Funderburk Senior Vice President - Nuclear Operations Director, Nuclear Licensing and Dominion Nuclear Connecticut, Inc. Operations Support Rope Ferry Road Dominion Resources Services, Inc.
Waterford, CT 06385 Innsbrook Technical Center 5000 Dominion Boulevard Mr. P. J. Parulis Glen Allen, VA 23060-6711 Manager - Nuclear Oversight Dominion Nuclear Connecticut, Inc.
Rope Ferry Road Waterford, CT 06385
Millstone Power Station, Unit No. 2 cc:
Mr. A. J. Jordan, Jr.
Director - Nuclear Engineering Dominion Nuclear Connecticut, Inc.
Rope Ferry Road Waterford, CT 06385 Mr. S. P. Sarver Director - Nuclear Station Operations and Maintenance Dominion Nuclear Connecticut, Inc.
Rope Ferry Road Waterford, CT 06385 Mr. David W. Dodson Licensing Supervisor Dominion Nuclear Connecticut, Inc.
Rope Ferry Road Waterford, CT 06385
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELAXATION OF THE REQUIREMENTS OF ORDER EA-03-009 REGARDING REACTOR PRESSURE VESSEL HEAD INSPECTIONS AT MILLSTONE POWER STATION, UNIT NO. 2 DOMINION NUCLEAR CONNECTICUT, INC.
DOCKET NO. 50-336
1.0 INTRODUCTION
On February 11, 2003, the U.S. Nuclear Regulatory Commission (NRC) issued Order EA-03-009 requiring specific inspections of the reactor pressure vessel (RPV) head and associated penetration nozzles at pressurized water reactors. The NRC issued an errata to the Order on March 14, 2003, to correct an administrative part of the Order related to requests for relaxation of the Order requirements.
Section IV.F of the Order states that the NRC may relax or rescind any of the Order requirements upon demonstration by the licensee of good cause.Section IV.F of the Order also states that a request for relaxation of the Order requirements for inspection of specific penetration nozzles shall address the following criteria: (1) the proposed alternative(s) for inspection of specific nozzles will provide an acceptable level of quality and safety, or (2) compliance with this Order for specific nozzles would result in hardship or unusual difficulty without a compensating increase in the level of quality and safety. This section of the Order states that requests for relaxation associated with specific penetration nozzles will be evaluated by the NRC staff using its procedure for evaluating proposed alternatives to the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) in accordance with Section 50.55a(a)(3) of Title 10 of the Code of Federal Regulations (10 CFR 50.55a(a)(3)).
Sections IV.A and IV.B of the Order provide criteria to categorize each plants RPV head with respect to its susceptibility to primary water stress corrosion cracking (PWSCC). For plants such as Millstone Power Station, Unit No. 2 (MP2), with RPV heads that are categorized as being highly susceptible to PWSCC,Section IV.C(1) of the Order requires the following inspections be performed every refueling outage:
- a. Bare metal visual examination of 100% of the RPV head surface (including 360E around each RPV head penetration nozzle), AND
- b. Either:
- i. Ultrasonic testing (UT) of each RPV head penetration nozzle (i.e., nozzle base material) from two (2) inches above the J-groove weld to the bottom of the nozzle and an assessment to determine if leakage has occurred into the interference fit zone, OR
ii. Eddy current testing or dye penetrant testing (PT) of the wetted surface of each J-groove weld and RPV head penetration nozzle base material to at least two (2) inches above the J-groove weld.
Footnote 3 of the Order provides specific criteria for inspection of repaired RPV head penetration nozzles.
Section IV.C(1)(b) of the Order requires that the same non-destructive examination (NDE) technique be used to inspect the entire population of RPV head penetration nozzles; combining techniques, or using one technique on one nozzle and the other technique on another nozzle, is not permitted.
By letter dated September 3, 2003, Dominion Nuclear Connecticut, Inc. (DNC) requested relaxation from the requirements in Section IV.C(1)(b) of the Order for MP2. The relaxation request was made pursuant to the procedure specified in Section IV.F of the Order.
Specifically, for inspection of the RPV head vent line penetration nozzle, DNC requested authorization to use a combination of UT on the nozzle base material, and PT on the nozzle J-groove weld. The relaxation was requested for the third 10-year interval of the inservice inspection program at MP2, which began on April 1, 1999, and ends on March 31, 2009. The authorization was requested until superceded by design changes to the RPV head or until superceded by changes made to 10 CFR 50.55a. As discussed in Section III of the Order, the long-term resolution of the RPV head penetration inspection requirements imposed by the Order is expected to involve changes to the ASME Code and to 10 CFR 50.55a.
2.0 PROPOSED ALTERNATIVE FOR RPV HEAD VENT PENETRATION NOZZLE 2.1 Licensees Proposed Alternative The licensees submittal states that the control element drive mechanism (CEDM) nozzles and the incore instrumentation (ICI) nozzles will be inspected using the UT technique as specified in Section IV.C(1)(b)(i) of the Order. However, for the RPV head vent line nozzle, the absence of an interference fit region between the nozzle and its RPV penetration prevents an acceptable performance of a leakage assessment using the UT technique, as required by the same Order section. Since the Order requires that only one of the two NDE techniques specified in Section IV.C(1)(b) of the Order be used to inspect the entire population of RPV head penetration nozzles (i.e., technique specified in Section IV.C(1)(b)(i) or Section IV.C(1)(b)(ii)),
DNC has determined that relaxation of the inspection requirements imposed in Order Section IV.C(1)(b) is necessary.
For the inspection of the RPV head vent line penetration nozzle, in lieu of the requirements in Section IV.C(1)(b)(i) of the Order, DNC requested authorization to perform UT of the nozzle base material from two inches above the J-groove weld to the bottom of the nozzle, and a PT of the wetted surface of the J-groove weld.
Contingent upon authorization of this relaxation request, DNC will provide in the 60-day report for MP2, as required by the Order, specific inspection information (i.e., extent of inspections and results of those inspections).
2.2 Licensees Basis for Proposed Alternative The licensee's submittal states that using only one of the NDE techniques specified in Section IV.C(1)(b) of the Order for the entire population of RPV head penetration nozzles limits the licensee's options without measurably increasing the level of quality and safety. DNC believes that using either inspection technique is sufficient to detect the PWSCC phenomena and that no significant benefit is gained by requiring the same technique to be used on all nozzles.
The configuration of the RPV head vent line nozzle at MP2 warrants using a different technique from the requirements in Section IV.C(1)(b)(i) of the Order. Specifically, the UT inspection that will be used to examine the CEDM and ICI nozzles is not suitable for the leakage assessment on the RPV head vent line nozzle due to the lack of an interference fit region on that nozzle.
Accordingly, DNC proposes to use a different technique, PT in addition to UT. DNC believes that the proposed alternative to allow the use of a combination of UT on the nozzle base material, and PT on the nozzle J-groove weld, maintains the level of quality and safety prescribed in Section IV.C(1)(b).
3.0 EVALUATION The NRC staffs review of this relaxation request is based on criterion (1) of Section IV.F of the Order which states:
The proposed alternative(s) for inspection of specific nozzles will provide an acceptable level of quality and safety.
Order EA-03-009 requires inspection of the entire population of RPV head penetration nozzles using only one of the techniques specified in Section IV.C(1)(b) of the Order; it does not permit the combined use of mixed NDE methods. The licensee stated it would inspect the CEDM and ICI nozzles using the UT inspection technique as specified in Section IV.C(1)(b)(i) of the Order.
However, unlike the CEDM and ICI nozzles, the RPV head vent line nozzle is a smaller diameter nozzle and is of a different configuration with no interference fit. As such, there is a slight gap between the nozzle and the vessel head. Performing the leakage assessment using only UT will not provide a completely meaningful assessment of the gap area intended by the Order due to the air/metal interface in the gap.
The licensees proposed alternative will provide an acceptable leakage assessment of the RPV head vent line nozzle to RPV head interface by performing inspections of the nozzle base material using UT on the nozzle and using PT on the nozzle J-groove weld. Since either inspection technique is capable of detecting PWSCC, the proposed alternative will provide a leakage assessment of the RPV head vent line nozzle. Therefore, the proposed alternative provides reasonable assurance of the structural integrity of the RPV head vent line nozzle and the associated J-groove weld.
4.0 CONCLUSION
The NRC staff concludes that DNC has demonstrated good cause for the requested relaxation and that the proposed alternative provides an acceptable level of quality and safety. Therefore, pursuant to Section IV.F of the Order, and 10 CFR 50.55a(a)(3), the NRC staff authorizes the proposed relaxation and alternative inspection of the RPV head vent line penetration nozzle at MP2 during the period while NRC Order EA-03-009 remains in effect.
When vessel head inspections are performed using ASME Code requirements, acceptance criteria, or qualified personnel, those activities and all related activities fall within the jurisdiction of the ASME Code. Therefore, Order-related inspection activities may be subject to third party review, including those by the Authorized Nuclear Inservice Inspector.
Principal Contributors: Z. Fu R. Ennis Date: October 14, 2003