ML20236M514
| ML20236M514 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 07/31/1987 |
| From: | Tam P Office of Nuclear Reactor Regulation |
| To: | Sieber J DUQUESNE LIGHT CO. |
| References | |
| TAC-65107, NUDOCS 8708110102 | |
| Download: ML20236M514 (3) | |
Text
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Docket No. 50-334 OUL 51 19?/
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Mr. J. D. Sieber, Vice President Nuclear Operations Duquesne Light Company Post Office Box 4 Shippingport, PA 15077
Dear Mr. Sieber:
SUBJECT:
BEAVER VALLEY UNIT 1 - ELIMINATION OF LARGE-BORE SNURBERS FROM PRIMARY LOOPS (TAC 65107) l By letters dated June 1 and 12, 1987, you requested our review of your l
proposal to eliminate certain large-bore snubbers from the primary coolent system by applying leak-before-break technology. Our review of those submittals is ongoing.
i Enclosed please find a description of the information we need to complete this review. We request your expedited response to this request. Prior to submittal, your staff may wish to discuss your proposed response with us in a meeting or telephone conference. We will then agree on a target date for your formal response.
The reporting and/or recordkeeping requirements of this request affect fewer than ten respondents; therefore, OMB clearance is not required under P.L.96-511.
i Sincerely, Peter S. Tam, Project Manager Project Directorate I-4 Divisioe of Reactor Projects I/II
Enclosure:
As stated cc w/ enclosure:
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y Mr. J. D. Sieber Beaver Valley 1 Power Station Ouquesne Light Company l-l cC' l
Mr. W. S. Lacey Pennsylvania Power Company l
Station Superintendent James R. Edgerly Duquesne Light Company Post Office Box 891 l
Beaver Valley Power Station flew Castle, Pennsylvania 16103 Post Office Box 4 Shippingport, Pennsylvania 15007 Mr. Jess T. Shumate Commissioner State of West Virginia Department Mr. S. Sovick, Acting Supervisor of Labor of Licensing 1800 Washington Street, East Duouesne Light Company Charleston, West Virginia 25305 Post Office Box 4 Shippingport, Pennsylvania 15077 David K. Heydinger, M.D.
State Director of Health Mr. John A. Levin State Department of Health Public Utility Commission 1800 Washington Street, East Post Office Box 3265 Charleston, West Virginia 25305-Harrisburg, Pennsylvania 17120 Regional Administrator, Region 1 Gerald Charnoff, Esquire U.S. Nuclear Regulatory Conmission Jay E. Silberg, Esquire 631 Park Avenue 1
Shaw, Pittman, Potts and Trowbridge King of Prussia, Pennsylvania 19406 2300 N Street, N.W.
Washington, DC 20037 Mr. R. Janati Bureau of Radiation Protection Charles E. Thomas, Esquire Pennysivania Department of Thomas and Thomas Environmental Resources
. 212 Locust Street P.O. Box 2063 Box 999 Harrisburg, Pennsylvania 17120 Harrisburg, Pennsylvania 17108 John D. Burrows, P.E.
Marvin Fein Director of Utilities.
Utility Counsel State of Ohio City of Pittsburgh Public Utilities Commission 313 City-County Building 180 East Broad Street Pittsburg, Pennsylvania 15219 Columbus, Ohio 43266-0573 Resident Inspector Pennsylvania Office of Consumer U.S. Nuclear Regulatory Commission Advocate Post Office Box 298 ATTN: Michael Bardee Shippingport, Pennsylvania 15077 1425 Strawberry Square Harrisburg, Pennsylvania 17120
4 REQUEST FOR ADDITIONAL INFORMATION
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ON ELIMINAT10N'0F POSTULATED PRIMARY. LOOP PIPE RUPTURES l'
AS A DESIGN BASIS
'(1) The primary loop piping and fittings were fabricated from cast stainless steel'. Describe whether the piping and fittings are centrifugally cast stainless steel or statically cast stainless steel. Also, identify the welding process of the primary loop and indicate if solution annealing was performed.
(2) The material properties were presented in Table 3-1 in Westinghouse report WCAP-11317., Describe whether the properties are plant specific data from certified material test reports (CMTRs) or Section III 1
Code-minimum values, at room temperature or operating temperature.
Provide the elastic modulus, yield strength, ultimate strength, and.
stress-strain curve, at the limiting location and at the operating temperature, that would be used in the leak-before-break (LBB) analyses.
(3) It appears that the same stress-strain relationship was used in the fracture stability and leakaoe calculations. The licensee should use the lower-bound stress-strain relationship for the stability evaluation and the average stress-strain relationship for the leakage evaluation.
(4) Linear elastic fracture mechanics (LEFM) was used for the fracture stability analysis. However, from the calculated fracture mechanics parameter J-integral "J it appears that the associated Irwin plane-stress plastic 20NP,zes are not small compared with the si half-crack length'"a". The licensee should use elastic-plastic fracture mechanics (EPFM)instead'ofLEFMprocedures. Similarly, the tearing modulus "T,pp" should be evaluated based on EPFM procedures.
- (5) Limit load analysis was used to estimate the size of a stable crack.
However, limit load analysis does not account for material toughness limitations.
In particular, low toughness thermally-aged cast stainless steel is involved in the present evaluation. The licensee should'use a fracture stability analysis which accounts for material toughness.
i (6) Since the primary loop was fabricated from materials having various toughness properties, load critical and toughness critical locations were discussed. However, the LBB evaluation margins should be demonstrated j
for the limiting location having the least favorable combination of i
stress and material properties. The limiting location may be defined j
from a fracture stability evaluation of the load critical and toughness critical locations.
Since the primary loop piping is of a similar size, the location with the smallest stable crack size under a combination of normal (pressure, deadweight, and thermal) and safe shutdown earthquake (SSE) loads, independent of leakage, is the limiting location for LBB evaluations.
1 (7) The limiting location as discussed in item 6 above should be evaluated to j
demonstrate that the LBB margins are satisfied. Specifically, the 1
margins are 10 on the leakage rate, 2 on the crack size, and 1.4 on the
{
applied load, as discussed in detail in NUREG-1061 Volume 3.
(Note that in the submittal, the licensee did not discuss'the margin of 1.4 on the applied load. The licensee should include this margin of 1.4 on the appliedloadintheLBBevaluations.)
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