ML19305E738
| ML19305E738 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 05/12/1980 |
| From: | Pappas H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Burstein S WISCONSIN ELECTRIC POWER CO. |
| References | |
| NUDOCS 8005200339 | |
| Download: ML19305E738 (1) | |
Text
l 80052007J4
)
ganco
,f'
+
o, UNITE D STATES TO e
f
,n NUCLEAR REGULATORY COMMISSION l
3 7q#. E
(
REGION 111 o,
[
799 ROOSEVELT ROAD
[
GLEN ELLYN, ILLINOIS 60137 MAY ! 2 S80 Docket No. 50-266 Docket No. 50-301 Wisconsin Electric Power Company ATTN: L. Sol Burstein Executive Vice President Power Plants 231 West Michigan Milwaukee, WI 53201 Gentlemen:
Due to an oversight, the attached " Enclosure A" to IE Information Notice No. 80-20 was omitted from our letter dated May 8, 1980.
Sincerely, 4
Helen Pappas, Chief Administrative Branch
Enclosure:
Attachment A to IE Information Notice No. 80-20 cc w/ encl:
Mr. G. A. Reed, Plant Manager Central Files Director, NRR/DPM Director, NRR/ DOR C. M. Trammell, ORB /NRR PDR Local PDR NSIC TIC Sandra A. Bast, Lakeshore Citizens for Safe Energy Mr. John J. Duffy, Chief Boiler Inspector, Department of Industry, Labor and Human Relations
IE Information Notice No. 80-20 Enclosure A DAVIS-BESSE EVENT OF APRIL 19, 1980 STATUS OF DAVIS-BESSE 1 PRIOR TO LOSS OF POWER TO BUSSES E-2 AND F-2:
1.
Refueling mode with RCS temperature at 90 F and level slightly below vessel head flange.
Head detension~ed with bolts in place.
Manway cover on top of OTSG removed.
Tygon tubing attached to lower vents of RCS hot leg for RCS level indication.
Decay heat loop 2 in service for RCS cooling.
2.
All non-nuclear instrument (NNI) power and Static Voltage Regulator YAR supplied from 13.8 KV Bus B via HBBF2.
13.8 K Bus A energized but not connected.
RPS and SFAS Channels 1 and 3 being supplied from YAR.
3.
Equipment Out of Service Source Range Channel 2 - Surveillance a.
i I
b.
Emergency Diesel Generator 1 - Maintenance, Lecay Heat Loop 1 - Maintenance.
c.
4.
Breakers for containment spray and RPI pumps racked out.
i SEQUENCE OF EVENTS TIME EVENT i
CAUSE/ COMMENTS 2:00 p.m.
Loos of power to Ground short on 13.8 KV breaker HBBF2 Busces E-2 and F-2 which caused breaker to open.
This (non-essential 480 interrupted power to busses E-2 and F-2 VAC) which were supplying all non-nuclear' instrument (NNI) power, channels 1 and 3 of the Reactor Protection System (RPS) and
.the Safety Features Actuation Signal (STAS),
the computer, and much of the control room indicators.
2:00 p.m.
STAS Level 5 (recircu-Two out of four logic tripped upon loss lacion ecde) actua-of Busses E-2 and F-2.
Actuation caused tion.
ECCS pump section valves from containment sump to open and ECCS pump sue. ion valves from Borated Water Storags Tank to close.
During valve travel times, gravity flow path existed from BWST to containment sump.
2:02 p.m.
Decay Heat (low Operator turned off only operating DH 1
pressure safety in-pump to avoid spillage of RCS vater to l
jection) flow secured containment via the tygon tubing for RCS by operator level indication and open SG manway.
2:33 p.m.
Partial restoration of power Power to Bus E 2 and SFAS channels 1 and 3 restored along with one channel of NNI. This restored all essential power for GC@@o 1
l l
l o
l
_2-TIME EVENT CAUSE/ COMMENTS 2:44 p.m.
, Attempt to reestab-Started DH pu=p 1-2 then stopped it when lish DH flow it was determined that air was in suction line.
Pump secured to prevent danage.
3:34 p.m.
Source Range Channel 2 energized.
4:00 p.m.
Restoration of Busses Busses restored sequentually as efforts to (480 VAC) F-2 F-21, progressed to isolate ground fault.
4:06 p.m.
F-22, and F-23 4:25 p.m.
DH flow restored DH pump 1-2 started af ter venting. RCS temperature at 170 F. DH flow bypassing 28 1956. '"" ** ' b'1"8 ""**" '"d ""***""
F 4:46 p.m.
Containment sump Precautionary measure to assure containment pump breakers sump water from BWST remained in gentainment, opened Incore TC's range from 161 to 164 F.
5:40 p.m.
Computer returned to Incore TC's range from 158 to 160 F.
service.
6:24 p.m.
DH flow directed RCS cooldown established at less than 25 F through cooler per hour.
RCS te erature at 150 F. Incore Ti rangefrom151to$580F.
9:50 p.m.
Power completely RCS temperature at approximately 115 F.
restored STATUS OF DAVIS.BESSE 1 AFTER RECOVERY FROM LOSS OF PORER TO BUSSES E-2 AND F-2:
1.
Refueling mode with RCS temperature at 115 Y and level slightly below vessel he flange. Head detensioned with bolts in place.
Manway cover on top of OTSC removed.
Tygon tubing attached to lower vents of RCS hot leg for RCS level indication.
Decay heat loop 2 in service for RCS cooling.
2.
Bus E-2 being supplied from 13.8 KV 3us A via breaker RAAE2 and Bus F-2 being supplied from 13.8 KV Bus 3 via breaker HBBF2.
3.
Decay heat loop filled, all tags clear.
Maintenance work restricted so restoration of system will be less than two hours.
4.
ECCS pusp suction valves (DH-9A and DH-9B) frem containment sump closed and breakers racked out.
This will prevent the suction of air into the decay
/
e-3-
heat loop during a level 5 actuation (recicculation mode) when there is no water in the.aump.
5.
Equip =ent Out of Service:
Emergency Diesel Generator 1 - maintenance 6.
Breakers for containment spray and HPI pumps racked out.
e e
4 4
0 6
v--
- -