ML19331C961
| ML19331C961 | |
| Person / Time | |
|---|---|
| Site: | Trojan File:Portland General Electric icon.png |
| Issue date: | 07/24/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Goodwin C PORTLAND GENERAL ELECTRIC CO. |
| References | |
| NUDOCS 8008200525 | |
| Download: ML19331C961 (1) | |
Text
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7/c UNITED STATES 8
NUCLEAR REGULATORY COMMISSION o
,I REGION V o
g 1990 N. CALIFORNIA BOULEVARD SUITE 202, WALNUT CREEK PLAZA 4,,, *,e WALNUT CREE K, CALIFORNIA 94596 July 24, 1980 Docket No. 50-344 Portland General Electric Company 121 S. W. Salmon Street Portland, Oregon 97204 Attention: Mr. Charles Goodwin Assistant Vice President Gentlemen:
The enclosed IE Bulletin No. 80-18, is forwarded for action. A written response is required.
In order to assist the NRC in evaluating the value/ impact of each Bulletin on licensees, it would be helpful if you would provide an estimate of the manpower expended in conduct of the review and preparation of the report (s) required by the Bulletin.
Please estimate separately the manpower associated with correc-tive actions necessary following identification of problems through the Bulletin.
If you desire additional information regarding this matter, please contact this office.
Sincerely, R. H. Engelken Director
Enclosures:
1.
List of Bulletins Recently Issued cc w/ enclosures:
F. C. Gaidos, PGE J. W. Lentsch, PGE C. P. Yundt, PGE 8008 00535 Q
9 SSINS flo.: 6820 Accession ?!o. :
U!!ITED STATES 8005050062 flUCLEAR REGULATORY COMMISSION OFFICE OF IflSPECTIO!i AtlD ENFORCEMENT WASHIt'GT0!!, D.C. 20555 July 24, 1980 IE Bulletin t!o. 80-18 MAlilTEilANCE OF ADEOUATE MINIMUM FLOW THRU CENTRIFUGAL CHARGING PUMPS FOLLOWIflG SECONDARY SIDE HIGH ENERGY LINE RUPTURE Description of Circumstances:
Letters similar to the May 8,1980 notification made pursuant to Title 10 CFR Part 21 (enclosure) were sent from Westinghouse to a number of operating plants and plants under construction (list, within enclosure) in early May, 1980.
The letters and the enclosed "Part 21" letter contain a complete description of the potential problem summcrized below. The letters indicated that under certain conditions the centrifugal charging pumps (CCPs) could be damaged due to lack of minimum flow before presently applicable safety injection (SI) termination criteria are met. The particular circumstances that could result in damage vary somew'e trom plant to plant, but involve unavail-r ability of the pressurizer power operated relief valves (PORVs), with operation of one or more CCPs repressurizing the reactor during SI following a seccndary system high energy line break. Since the SI signal automatically isolates the CCP mini-flow return line, the flow through the CCPs is determined by the individual pump characteristic head vs. flow curve, the pressurizer safety valve setpoint, and the flow resistances and pressure losses in the piping and in the reactor core. That minimum flow may not be adequate to insure pump cooling, and resulting pump damage could violate design criteria before current SI termination criteria are met.
Westinghouse recommends that plant specific calculatQ + oclined in the letter (enclosure) be performed to determine if adw;n minimum flow is assured under all conditions. If adequate minir 4 f av.s r.ot assured, Westinghouse recommends specific equipment and ye ' c m3difications which will result in adequate minimum flow. The ecommded modifications assure availability of the necessary minimum flow by assuring that the mini-flow bypass line will be open when needed, but will be closed at lower pressures when the extra flow resulting from bypass line closure might be necessary for core cooling.
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