ML20216G869
| ML20216G869 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 09/09/1997 |
| From: | Muench R WOLF CREEK NUCLEAR OPERATING CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| ET-97-0105, ET-97-105, NUDOCS 9709160075 | |
| Download: ML20216G869 (4) | |
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W@ NUCLEAR OPERATING CO LF CREEK Richard A. Muench Vce president Engineenng September 9, 1997 ET 97-0105 U. S. Nuclear Regulatory Commission 4
ATTN:
Document Control Desk Mail Station Pl-137 Washington, D. C.
205b5
Reference:
Subject:
Docket No. 50-482: Revision to Relief Request 12R-22 Gentlemen:
Reference 1 transmitted the Wolf Creek Generating Station request for relici to use the provisions of IWA-5244 of the 1995 Addenda of Section XI for testing of buried piping.
Reference 2 transmitted additional informatim in response to NRC Staff questions.
Based on discussions with the NFC Staff on
.1uly 10, 1997 and August 21, 1997, Wolf Creek Nuclear Operatir.g Corporation
-(WCNOC) is revising and resubmitting Relief Request 12R-22.
The revision requests the use of an alternative testing provision for the buried portion of the supply piping for the Essential Service Water System.
The buried supply-side piping of the Energency Fuel-Oil System will be addressed la a separate submittal.
Pursuant to the provisions of 10 CFR 50. 55a (a) (3) (1), WCNOC requests approval for use of the attached alternative to the testing provisions provided in the 1989 Edition of ASME Section XI.
The attached revised relief. reauest provides the justification for the use of the alternative testing provision.
In addition, the attached relief request includes a determination that use of the alternative testing provisions provide an acceptable level of quality and safety.
Based on a request from the NRC Staff, information will be submitted concerning the acceptable through-wall leakage rate in the buried Essential Service' Water (ESW) System piping, as soon as preparation of that information is completed.
Although WCNOC will submit this information, the relief request does not request any change to the provisions for establishing acceptable leakage contained in the 1989. Edition of Section XI.
These currently approved provisions require the Owner to establish the limits for acceptable Jeakage loss in buried piping.
The acceptable through-wall leakage rate will be established in accordance with IWA-5244(a) and IWA-5250 (a) (1) and will meet WCCS conditions for continued operations.
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ET 97-0105 Page 2 of ?
Approval for use of this relief request is requested by Septen.ber 26, 1997, ono week prior to the beginning of the next ref ueling outage scheduled to begin October 4, 1997.
The testing of the buried, supply-side ESW piping is seneduled for this upcoming refueling outage.
If you should have any questions regarding this request, _please contact me at (316) 364-8831, extension 4034, or Mr. Richard D.
Flannigan at extension 4500.
Very truly yourai, Rich rd A. Muench RAM /jad
Attachment:
Relief Request 12R-22 cc:
W.
D. Johnson (NRC), w/a E. W. Merschoff (NRC), w/a J.
F. Ringwald (NRC), w/a J.
C. Stone (NRC), w/a J
B A
4 s
Attachment to ET 97-0105 Page 1 of 2 RELIEF REQUEST 12R-22 Component Identifications Buried Class 3 piping on the supply-side of the Essential Service Water System Category:
ASME Section XI 1989 Edition, Table IWD-2500-1, Examination Categories D-A, Item Number D1.10 4
Examination Requirements:
The pressure retaining components within the boundary of each system shall be pressure tested and VT-2 examined each inspection period and hydrostatically tested and VT-2 examined each inspection interval.
VT-2 examination of buried components is performed in accordance with IWA-5244.
Relief Requested:
Pursuant to 10 CFR 50.55a (a) (3) (1), relief is requested for the Second 10-Year Inspection Interval.
Relief is requested to use an alternative testing provision to the currently approved provisions in 10 CFR 50.55a(b).
The proposed alternative provision stated below is requested in the absence of applicable provisions in IWA-5244 in the 1989 Edition of ASME Section XI.
All other provisions of the 1989 Edition would continue to be met, except as specifically approved by other relief requests.
The Essential Service Water (EWS) System is a redundant, isolable system.
In the absence of Section XI provisions for redundant, isolable systems, WCGS proposes to perform a rate of preseure loss test of the underground supply piping of the ESW System in accordance with the nonredundant, isolable system provisions, subparagraph IWA-5244(a) in the 1989 Edition of Section XI.
A rate of pressure loss from the test volume would be quantified by measuring the rate of loss out of identified boundary valves compared with the rate of makeup to the system.
For satisfactory test performance with the normally expected test boundary conditions, the acceptable difference between system makeup and _ identified boundary leakage would be set at 11 gallons per minute (gpm).
The 11 gpm is based on tolerances in measurements and is set as' low as reasonably measurable in accordance with the NRC Staff request.
Although not part of this relief request, flow rates beyond 11 gpm will be evaluated for acceptance in accordance with IWA-5244(a) and IWA-5250 (a) (1).
Basis For Relief IWA-5244 of the 1989 Edition of ASME Section XI, as approved by 10 CFR 50.55a, does not provide provisions for testing buried systems that are " redundant,"
and, " isolable," such as the case for the WCNOC ESW System.
Use of the proposed relief request would allow WCNOC to perform the same test prescribed in IWA-524 4 (a) for nonredundant, isolable systems.
The Code prescribed " rate of pressure loss" test would measure the flow rate in gpm going into the isolated (supply side) ESW buried pressure boundary compared to measured leakage (gpm) through boundary valves, For satisfactory test performance, the acceptance criteria for comparison of the two measured rates will be 11 gpm.
This rate has been established to comply with the request of the NRC Staff for the acceptance criteria to be as small as reasonably possible to measure.
The i
Attachment to ET 97-0105 Page 2 of 2 4
RELIEF REQUEST I2R-22 acceptance criteria was established based on reasonable tolerances in measurement of the makeup flow going into the system and measurement of the leakage coming out of the normally expected test boundary conditions (three large butterfly boundary valves).
Flow rates above 11 gpm, indicating probable through-wall leakage, will be evaluated for acceptance in accordance with the NRC currently approved provisions in IWA-5244 (a) and IWA-5250 (a) (1) in the 1989 Edition of Section XI.
At the Staff's request, WCNOC will submit information on the acceptable through-wall leakage rate in the buried ESW piping, as soon as preparation of that information is completed.
Although WCNOC will submit this information, this relief. request does not request any change to the provisions for establishing acceptable leakage in buried piping contained in the currently approved Section XI.
These currently approved provisions require the Owner to establish the limits for acceptable leakage loss in buri ed piping.
The acceptable through-wall leakage rate will be established in accordance with IWA-5244(a) and IWA-5250 (a ) (1) and will meet WCGS conditions for continued operations.
IWA-5250 (a ) (1) requires corrective measures, i.e.,
locating and repairing or rep} acing the leaking buried piping, when the Owner specified acceptance criteria has been exceeded.
However, confirmed leakage will be monitored and evaluated by the existing WCNOC corrective action program for appropriate action.
The ASME Code has recognized that provisions for testing buried, redundant, isolable piping were not addressed in previous Editions of Section XI.
In the 1995 Addenda of Section XI, IWA-5244 was revised to categorize requirements based on isolability alone.
The Code revision broadens the requirements for isolable systems by requiring the same provisions for all isolable buried components, whether they are redundant or nonredundant systems.
This Code revision published in the 1995 Addenda was approved by the Code consensus process.
The Code consensus process determined that redundancy vs. nonredundancy-was not appropriate criteria for setting requirements.
The WCNOC proposed alternative uses existing test methodology and acceptance criteria determination in the 1989 Edition and applies that methodology regardless of whether the system is redundant or nonredundant.
The proposed alternative is also in compliance with the 1995 Addenda of IWA-5244.
In the absence of testing provisions for redundant, isolable ESW
- System, the proposed alternative demonstrates an acceptable level of quality and safety.
.