ML19321A687
| ML19321A687 | |
| Person / Time | |
|---|---|
| Issue date: | 06/24/1980 |
| From: | Pappas H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Wright G ILLINOIS, STATE OF |
| References | |
| NUDOCS 8007240065 | |
| Download: ML19321A687 (2) | |
Text
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NUCLEAR REGULATORY COMMISSION g'
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799 ROOSEVELT ROAD Q
GLEN ELLYN, ILLINOIS 60137 QUN 2 4 G80 State of Illinois Department of Public Health ATTN:
Mr. Gary N. Wright, Chief Division of Nuclear Safety 535 West Jefferson Street Springfield, IL 62761 Gentlemen:
The attached IE Circular No. 80-15 titled " Loss of Reactor Coolant Pump Cooling and Natural Circulation Cooldown" was sent to the licensees listed below for information on June 20, 1980:
Anserican Electric Power Service Corporation Indiana and Michigan Power Company D. C. Cook 1, 2 (50-315, 50-316)
Cincinnati Gas & Electric Company Zimmer (50-358)
Cleveland Electric Illuminating Company Perry 1, 2 (50-440, 50-441)
Commonwealth Editon Company Braidwood 1, 2 (50-456, 50-457)
Byron 1, 2 (50-454, 50-455)
LaSalle 1, 2 (50-373, 50-374)
Dresden 1, 2 (50-10, 50-237, 50-249)
Quad-Cities 1, 2 (50-254, 50-265)
Zion 1, 2 (50-295, 50-304)
Consumers Power Company Big Rock Point (50-155)
Midland 1, 2 (50-329, 50-330)
Palisades (50-255)
Dairyland Power Cooperative LACBWR (50-409)
Detroit Edison Company Fermi 2 (50-341)
Illinois Power Company Clinton 1, 2 (50-461, 50-462)
- df 8007240 d
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- State of Illinois 'JUN 2 4 G80-Iowa Electric Light & Power Company Duane Arnold (50-331)
Northern Indiana Public Service Company Bailly (50-367)
Northern States Power Company Monticello (50-263)
Prairie Island 1, 2 (50-282, 50-306)
Public Service of Indiana Marble Hill 1, 2 (50-546, 50-547)
Toledo Edison Company Davis-Besse 1 (50-346)
Union Electric Company Callaway 1, 2 (50-483, 50-486)
Wisconsin Electric Power Company Point Beach 1, 2 (50-266, 50-301)
Wisconsin Public Service Corporation Kewaunee (50-305)
Sincerely, I
Helen Pappas, Chief Administrative Branch
Enclosure:
IE Circular No. 80-15 cc w/ encl:
Mr. D.li.-Kane, Sargent1& Lundy Central Files Reproduction Unit NRC 20b Local PDR NSIC TIC.
5
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 1 of 4 LOSS OF REACTOR COOLANT PUMP COOLING AND NATURAL CIRCULATION C00LDOWN Description of Circumstances:
This Circular contains information on the St. Lucie Unit I response to a total loss of component cooling water (CCW) 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 I 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 (SCP) to fail shut. The terminal shcrt 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 initiated 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.
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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 chagingryg.tlwaupypa wry. ljng-,,777 1m n =" ~ ' & ~ m T " " "
Pressurizer level continued variations {V '
the cooldown and depressurization conti RCS loops, pressurizer level decreased (j DUPLICATE DOCUMENT increase in level when charging throughi two minute interval while charging into[j Entire document previously at 88 gpm, pressurizer IcVel rose at a l
entered into system under:
than the charging flowrate.
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