ML19321A700
| ML19321A700 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 05/08/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Collier A OFFSHORE POWER SYSTEMS (SUBS. OF WESTINGHOUSE ELECTRI |
| References | |
| NUDOCS 8007240084 | |
| Download: ML19321A700 (1) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION n
I E REGION II o
101 MARIETTA ST., N.W., SUITE 3100 o
ATLANTA, GEORGIA 30303 MAY 8 1980 In Reply Refer To:
RlI:JPO Offshore Power Systems Attn:
A. R. Collier, President
. O. Box 8000 Jacksonville, Florida 32211 i
Gentlemen:
The enclosed Information Notice provides early notification of an event that may have safety significance. Accordingly, you should review the Information Notice for possible applicability to your facility.
No specific action or response is requested at this time; however, con-tingent upon the results of further staff evaluation, a Bulletin or Circular recommending or requesting specific licensee actions may be issued.
If you have questions regarding this matter, please contact me.
Sincerely,
- _A N'
MM James P. O'Reilly Director
Enclosures:
1.
IE Int'ormation Notice No. 80-20 2.
List of Recently Issued IE Information Notices I *
~
e 8007240
SSINS No.: 6835 Accession No.:
UNITED STATES 8005050073 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 IE Circular No. 80-15 Date:
June 20, 1980 Page ' of 4 LOSS OF REACTOR COOLANT PUMP COOLING AND NATURAL CIRCULATION JOLDOWN Description of Circumstances:
This Circular contains information on the St. Lucie Unit I response to a total loss of component cooling water i CW) flow to reactor coolant pumps.
Pres-surizer level and primary system pressure response indicate that voids were formed in the reactor vessel during the ensuing natural circulation cooldown.
The void was believed to have been steam in the area located directly under the reactor vessel head.
At time 0226 on June 11, 1980 with St. Lucie Unit 1 at full power, an electrical short across a solenoid valve terminal board caused one of two series containment isolation valves in the CCW return from all reactor coolant pumps (RCP) to fail shut. The terminal short resulted from environmental effects of a minor steam leak in the immediate vicinity of the solenoid valve.
After unsuccessful attempts to restore CCW flow, the reactor was tripped manually at time 0233. Within two minutes, all four RCPs were also manually tripped. A natural circulation cooldown was initiateo at approximately 0300.
Component cooling water flow to RCPs was restored at 0400. The solenoid operated air valve whose terminal board had shorted was bypassed with a temporary air line to reopen the CCW valve (HCV-14-6). Although variations in seal leakoff flowrates were observed, the seals on the four idle RCPs did not fail.
St. Lucie has Byron Jackson reactor coolant pumps with three stage mechanical seals plus a vapor seal.
Controlled reactor coolant bleedoff flow is used for seal cooling and lubrication. The pumps do not have a seal water injection system.
The natural circulation cooldown continued uneventfully until after time 0600.
The highest cooldown rate achieved was approximately 65 to 70 F per hour.
Between 0600 and 0630 RCS pressure was reduced from 1140 to 690 psi by charging water through the pressurizer auxiliary spray line.
Pressurizer level increased rapidly around 0700 while chapipAvif,the.Juviyns mre.-Lin31.x...
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Pressurizer level continued variations p
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the cooldown and depressurization conti M
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RCS loops, pressurizer level decreased gj DUPLICATE DOCUMENT increase in level when charging throughsJ two minute interval while charging into?j Entire document previously l
at 88 gpm, pressurizer level rose at a pi entered into system under:
than the charging flowrate.
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