ML19256B330
| ML19256B330 | |
| Person / Time | |
|---|---|
| Site: | Wolf Creek  |
| Issue date: | 04/21/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Koester G KANSAS GAS & ELECTRIC CO. |
| References | |
| NUDOCS 7906110003 | |
| Download: ML19256B330 (1) | |
Text
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UNITED STATES NUCLE AR REGULATORY COMMISSION
,o REGION IV
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611 RYAN PLAZA DRIVE. SUITE 1000 g((
ARLINGTON, TEXAS 76011 o
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%*'vnf April 21,1979 In Reply Refer To:
RIV Docket flo. STil 50-482/IE Bulletin 79-05B Kansas Gas and Electric Company ATTN: Mr. Glenn L. Koester Vice President-0perations P. O. Box 208 Wichita, Kansas 67201 Gentlemen:
The enclosed IE Bulletin 79-05B is forwarded to you for information.
flo written response is required. We have also enclosed copies of recommendations of the ACRS to the Commission for your information.
If you desire additional information regarding this matter, please contact this office.
Sincerely, N68w-/h Karl V. Seyfrit Director
Enclosures:
1.
IE Bulletin No.79-05B with enclosures 2.
ACRS Recomendations to the Commission dated April 18, 1979 and April 20, 1979 3.
List of IE Bulletins Issued in the Last Twelve l'onths cc w/ enclosures:
Messrs.
Nicholas A. Petrick, SilVPPS D. T. McPhee, Kansas Cit 3 Power and Light Company Gerald Charnoff, Shaw, Pittman, Potts & Trowbridge E. W. Creel, Kansas Gas and Electric Company 790611000I Q
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UNITED 5TATES c-e.:m :-
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NUCLEAR REGULATORY COMMISSION EMr OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON,- DC 20555 C
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APRIL 21,1979 Ems
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IE Bulletin 79-05B
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sasc NUCLEAR INCIDENT AT THREE MILE ISLAND - SUPPLEMENT i=.tr
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Description of Circumstances:.
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Continued NRC evaluation of the nuclear incident at Three Mile Island 5*Nb M
Unit 2 has identified measures in addition to those discussed in IE Bulletin 79-05 and 79-05A which should be acted upon by licensees with reactors designed by B&W.
As discussed in Item 4.c. of Actions to be
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following a trancient or accident is to provide forced flow using 2-reactor coolant pumps.
?#Y It appears that natural circulation was not successfully achieved upon EEH WE" securing the reactor coolant pumps-during the first two hours of the Three Mile Island (TMI) No. 2 incident of March 28, 1979 Initiation C ~~~
of natural circulation was -inhibited by significant coolant voids, M55 possibly aggravated by release of noncondensible gases, in the primary
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coolant system. To avoid this potential for interference with natural I~~
circulation, the operator should ensure that the primary system is subcooled, and remains subcooled, before any atteropt is made to establish natural circulation.
y Natural circulation in Babcock and Wilcox reactor systems is enhanced by 2 '~a.
W maintaining a relatively high water icvel on the secondary side of the once through steam generators (OTSG).
It is also promoted by injection of auxiliary feedwater at the upper nozzles in the OTSGs. The integrated
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Control System automatically sets the OTSG level setpoint to 50% on the
=+s; operating range when all reactor coolant pumps (RCP) are secured.
- However,
'r.!.it in unusual or abnomal situations, manual actions by the operator to F =-
increase steam generator level will enhance natural circulation capability 5e in anticipation of a possible loss of operation of the reactor coolant pumps.
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As stated previously, forced flow of primary coolant through the core is G~i preferred to natural circulation.
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Other means of reducing the possibility of void formation in the reactor s%;r coolant system are:
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Minimize the operation of th DUPLICATE DOCUMENT i'5"f-the pressurizer and thereby re
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reduction by a blowdown throug ntire document previously
' Mif entered into system under:
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