ML17056C184
| ML17056C184 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 12/24/1992 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML17056C183 | List: |
| References | |
| NUDOCS 9212300248 | |
| Download: ML17056C184 (12) | |
Text
gD,S REGlgg Cy A,
OO 0
Cy o~'p
>>>>*<<+
UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555 ENCLOSURE 2
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION SCHEDULAR EXEMPTION FROM APPENDIX J INTERVAL FOR LOCAL LEAK RATE TESTING OF CONTAINMENT ISOLATION VALVES NIAGARA MOHAWK POWER CORPORATION NINE MILE POINT NUCLEAR STATION UNIT NO.
1 DOCKET NO. 50-220
- 1. 0 INTRODUCTION By letter dated November 3,
- 1992, Niagara Mohawk Power Corporation (NHPC),
requested a schedular exemption pursuant to 10 CFR 50.12(a) from the requirements of 10 CFR 50, Appendix J, Section III.D.3.
This letter superseded a
NMPC application dated October 14, 1992.
NMPC requested temporary relief from the requirement to perform local leak rate tests (LLRTs) at intervals of no greater than 2 years for 39 Type C tests.
A one-time only
- delay, up to a maximum of 7 weeks, was requested for the performance of these leakage tests.
NMPC's request was necessitated by a proposed delay in the start of the next refueling outage (RFO-12) of Nine Mile Point Nuclear Station Unit No.
1 (NHP1) from January 2,
1993, to February 19, 1993.
The schedular exemption is required to permit NMPC to operate NMPl until February 19,
- 1993, the proposed start date for RFO-12.
The refueling outage is currently scheduled to begin on January 2,
1993, with an end date of about February 25, 1993.
- However, based on projections from the New York Power Pool (NYPP), the current -schedule may impact the ability of the NYPP to provide reliable power during the winter peak load period.
Accounting for planned maintenance, required reserves, and normal unplanned
- outages, the NYPP is projecting net margin deficiencies during the period January 3,
- 1993, through February 20, 1993.
Consequently, NMPC has determined that the most prudent and effective course of action would be to delay the start of RFO-12 approximately 7 weeks until February 19, 1993.
NHPC has stated that during the forced outage that began on Hay 1,
- 1992, and ended on August 8, 1992, it recognized that the start of RF0-12, originally scheduled to begin on September 11,
- 1992, would be impacted due to insufficient fuel burnup.
The current outage start date of January 2,
- 1993, was established at that time, and NMPC performed the Types B and C leak tests during the forced outage required to support the revised start date.
NHPC became aware of the NYPP projections of net margin deficiencies for the period January 3,
- 1993, through February 20,
- 1993, subsequent to the startup from the forced outage.
9iaa30Oi~8 mam+
PDR ADOCK 05000220 P
II
~EL The 39 Type C tests included in the exemption request are listed in Table 1.
NHPC has determined that these Type C tests of containment isolation valves cannot be performed during normal power operations for one or more of the following reasons:
a 0 b.
C.
d.
the valves are inaccessible due to their location in the drywell; the valves are in normally operating systems which cannot be physically tested; testing of a valve would require isolation of a system normally in service or available for service; a boundary valve required for performance of the Type C test cannot be exercised because it is inaccessible due to its location in the drywell.
The licensee has performed an analysis of the past leak rate history of the 39 containment isolation valves in question.
The penetrations included in the licensee's schedular exemption request represent approximately 45 percent of the Type C penetrations at NHPl, but only 6.2 percent of the total "as-left" leakage at the beginning of the current operating cycle.
.The total "as-left" leakage for all Types B and C penetrations was 0.24 L, and the total "as-left" from all penetrations covered by the proposed exemption was 0.015 L,.
The combined leakage from the penetrations addressed in the exemption went from an "as-left" value of 0.016 L to an "as-found" value of 0.05 L, during the 2-year interval prior to tfie current operating cycle.
During the 2-year period prior to that, the combined leakage from these penetrations went from an "as-left" value of 0.0224 L, to an "as-found" value of 0.095 L,.
Based on the most recent "as-left" leakage of 0.015 L, the historical performance of these penetrations, and a maximum increase oV 7 percent in the surveillance interval, the licensee has determined that the maximum combined leakage from these penetrations would not be expected to exceed 0.1 L,.
This provides reasonable assurance that the requested surveillance interval extension will not result in the Types B and C leakage total exceeding the 0.6 L, limit of 10 CFR Part 50, Appendix J.
The staff notes that the 2-year interval requirement for Type C components is intended to be often enough to prevent significant deterioration from occurring and long enough to permit the tests to be performed during plant outages.
Leak rate testing of the penetrations during plant shutdown is preferable because of the lower radiation exposure to plant personnel.
In
- addition, as previously noted, some penetrations cannot be tested at power.
For penetrations that cannot be tested at power, or for which testing at power is inadvisable, the increase in confidence of containment integrity following a successful test is not significant enough to justify a plant shutdown specifically to perform the tests within the 2-year time period, considering the leak rate history of the penetrations addressed by the exemption.
~LEI Based on the above evaluation, the staff finds the requested schedular exemption, to allow the Type C test intervals of the 39 valves listed in Table 1 to be extended to the refueling outage which will begin no later than February 19, 1993, to be acceptable.
To provide adequate time for plant shut down, the exemption should expire on February 20, 1993.
Attachment:
Appendix J Exemption Request/
Impacted Components Table 1
Principal Contributor:
J.
Henning Date:
December 24, 1992
I
.I
TABLE 1 NINE MILEPOINT UNITI DOCKET NO. 50-220 DPR-63 COMPONENT. ID COMPONENT DESCRIFrION 0141 Main Steam Line Loop 11 Inboard Isolation Valve 0142 Main Steam Line Loop 12 Inboard Isolation Valve 01-03 Main Steam Line Loop 11 Outboard Isolation Valve 3141R Feedwater System Loop 11 Outboard Isolation Valve 3147 Feedwater System Loop 11 Inboard Isolation Valve 3148 Feedwater System Loop 12 Inboard Isolation Valve 42.142 Liquid Poison Inboard Isolation Valve 42.143 Liquid Poison Outboard Isolation Valve 110-127 Reactor Recirculation Sample Line Inboard Isolation Valve 110-128 Reactor Recirculation Sample Line Outboard Isolation Valve 122-03 Post Accident Sample Line Inboard Isolation Valve 201.2-24 H,O, ¹12 Sample Stream D Outboard Isolation Valve 201.2-26 H,O, ¹12 Sample Stream C Outboard Isolation Valve 201,2-30 H,O, ¹12 Sample Stream B Outboard Isolation Valve 201.2-70 H,O, ¹12 Return Inboard Isolation Valve 201.2-71 H,O, ¹12 Return Outboard Isolation Valve 201.2-25 H,O, ¹12 Sample Stream C Inboard Isolation Valve 201.741 H,O, ¹11 Sample Stream B Inboard Isolation Valve 201.742 QO, ¹11 Sample Stream B Outboard Isolation Valve 201.743 QO, ¹11 Sample Stream A Inboard Isolation Valve 201.744 QQ ¹11 Sample Stream A Outboard Isolation Valve 201.748 Drywell CAM Supply Inboard Isolation Valve 201.7-09 Drywell CAM Supply Outboard Isolation Valve 201.7-10 Drywell CAM Return Inboard Isolation Valve 201.7-11 Drywell CAM Return Outboard Isolation Valve 201.243 Drywell N, Makeup Outboard Isolation Valve 201.2-32 Drywell N, Makeup Inboard Isolation Valve
~V V'
Cg',
APPENDIX J EXEMFHON REQUEST/MPACTED COMPONEN'I5 (Cont'd)
COMPOMXF@(
g';,.".;"':;:-','"".'.:
'";-',"...;'OMPONENT DESCRIPTION";
'01.246 Torus N, Makeup Outboard Isolation Valve 201.2-33 Torus N, Makeup Inboard Isolation Valve 20147, 08 Torus AirVent and Fill Inboard and Outboard Isolation Valves 201-16, 17 Tours N, Vent and Fill Inboard and Outboard Isolation Valves 201.2-109 H,O, ¹11 Return Inboard Isolation Valve 201.2-110 H,O, ¹11 Sample Stream C Outboard Isolation Valve 201.2-111 H,O, ¹11 Sample Stream C Inboard Isolation Valve 201.2-112 H,O, ¹11 Return Outboard Isolation Valve 201.1M Post-LOCA Vent Loop 11 Inboard Isolation Valve 201.1-11 Post-LOCA Vent Loop 11 Outboard Isolation Valve 201.1-14 Post-LOCA Vent Loop 12 Inboard Isolation Valve 201.1-16 Post-LOCA Vent Loop 12 Outboard Isolation Valve
I
Hr.
B.
Ral ph Syl vi a December 24, 1992 Copies of the Exemption and the NRC staff's supporting safety evaluation are enclosed.
The Exemption has been forwarded to the Office of the Federal Register for publication.
Sincerely, Original signed by:
Enclosures:
1.
Exemption 2.
Safety Evaluation cc w/enclosures:
See next page Robert A. Capra, Director Project Directorate I-1 Division of Reactor Projects - I/II Office of Nuclear Reactor Regulation Distribution:
'.Docket File NRC 8 Local PDRs T. Murley/F. Hiraglia, 12/G/18 J.
- Partlow, 12/G/18 B. Grimes, 9/A/2 J.
Lieberman, 7/H/5 S.
Varga J.
Calvo R. A. Capra C.
Vogan J.
Henning D. Brinkman
- OGC, C. HcCracken, 8/D/1 E. Jordan, 3701 MNBB G. Hill (4)
ACRS (10)
OPA OC/LFDCB Plant File V. HcCree, 17/G/21 C. Cowgill, RGN-1 PDI-1:LA PDI-1'H PDI-1: PH SPLB OGC PDI-1 '
CVo an JHennin
- s DBrinkman A CMcCracken C.
a !-C C)
RACa ra AD
~~/4 /92 la/
/92 D:D Ia/7 /92
/
/92
/92
> ~ /8>/92 JCalvo
/Z 29 92 ar
/92 OFFICIAL R CO D COPY FILENAME: NM184712. EXE
E
~
1