ML19344A741
| ML19344A741 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 07/24/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Woolever E DUQUESNE LIGHT CO. |
| References | |
| NUDOCS 8008220118 | |
| Download: ML19344A741 (1) | |
Text
. _ _ _ _ _ _ _
p it:q e
+
o UNITED STATES
~,,
[
g NUCLEAR REGULATORY COMMISSION G
j REGION 1 e
4 631 PARK AVENUE 4'+,+....g',
o KING OF PRUSSIA, PENNSYLVANI A 19406 July 24, 1980 Docket No. 50-412 Duquesne Light Company ATTN:
Mr. E. J. Woolever Vice President 435 Sixth Avenue Pittsburgh, Pennsylvania 15219 Gentlemen:
The enclosed IE Bulletin No. 80-18, " Maintenance of Adequate Minimum Flow Thru Centrifugal Charging Pumps Following Secondary Side High Energy Line Ruptu: e,"
is forwarded to you for information.
No written response is required. If you desire additional information regarding this matter, please contact this office.
Sincerely,
'O-Vl'l.$$$zuu 8 yce H. Grier irector Enclos'ures:
1.
IE Bulletin No. 80-18 and Enclosure with 2 Attachments 2.
List of Recently Issued IE Bulletins CONTACT:
E. G. Greenman (215-337-5267) cc w/encls:
R. J. Washabaugh, Quality Assurance Manager l
i 8 0082 2 0 llg
i l
SSINS No.: 6820 Accession No.:
UNITED STATES 8005050062 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION Atia ENFORCEMENT WASHINGTON, D.C. 20555 IE Bulletin No. 80-18 Date:
July 24,1980 MAINTENANCE OF ADEQUATE MINIMUM FLOW THRU CENTRIFUGAL CHARGING PUMPS FOLLOWING 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 enclose' "Part 21" letter contain a complete description d
of the potential problem summarized 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 circumstar.ces that could result in damage vary somewhat from plant to plant, but involve unavail-ability of the pressurizer power operated relief valves (PORVs), with operation of one or more CCPs repressurizing the reactor during SI following a secondary 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 ccoling, and resulting pump damage could violate design criteria before current SI termination criteria are met.
Westinghouse recommends that plant specific calculations outlined in the letter (enclosure) be performed to determine if adequate minimum flow is assured under all conditions. If adequate minimum flow is not assured, Westinghouse recommends specific equipment and procedure modifications which will result in adequate minimum flow. The recommended 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.
DUPLICATE DOCUMENT d
Entire document previously entered into system under:
g 90 M c P O6 L ANo d
No. of pages:
/3 WG}.;Q
~L+ : XLL%
.