ML19242D603
| ML19242D603 | |
| Person / Time | |
|---|---|
| Site: | Hatch  |
| Issue date: | 07/31/1979 |
| From: | GEORGIA POWER CO. |
| To: | |
| Shared Package | |
| ML19242D601 | List: |
| References | |
| ZAR-790718, NUDOCS 7908150500 | |
| Download: ML19242D603 (1) | |
Text
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SPECIAL REPORT LOW WATER LEVEL IN FIRE TA NK S DOCKET 50 766 9
July ll, lo7n
.---Initial Condition
-Ig?7 Jn at aheut 2200 CST during enoration of Unit 2 at 1902 MWt n
('93 MWe) and Unit 1 shutdown for refuelinR/ maintenance, the Unit ?
circulating water system was being chlorinatad.
Water for the chlorination process was obtained from the fire orotection system since the normal source of water was unavailable due to Unit 1 being shutdown.
9
_N a t u_r.e..o f O c c u r r e n c e :
At about 2200 CST the water levels in the two fire tanks decreased to below the required level of 270,000 gallons as required in Unit 1 Tech Spec Section 3.13.2 and Unit 2 Tech Spec Section 3.7.6.1.
It is estimated that at least 206,000 gallons and 234,000 gallons were in the tanks when the low Invel was discovered.
Immediate Corrective Action:
The fire tank levels were returned to greater than ?7C,000 gallons within one hour after discovery of the low levels.
Cause:
The deep well pumps which suop1v water to the fire tanks had overpaessurized and tripped.
Had they not tripped, these oumos would have had adequate flow caoacity to keeo up with the chlorination requi ements.
_S u_ o_ p l _e m e n t a l Corrective Action _:
A new source of water supply for the chlorination systen is b e '. n g angineered to eliminate the need for using fire protection water for ch!crination of Unit 2 when the Unit circulating water avsten is wt of service.
in investigation aevealed that oressure 3 witch Pol-F OS, which trios the well pumps, was set lows" than its design value of 140 ost The switch was re-calibrated to the correct valae.
Statg of Redundant or Ba c k.: o Systems:
The service water cross-tie with the fire protection system was ava'lable during the period of low level.
_I _m p a c t to Other Units:
'he fi"e tank low levels impacted both unit 3 stace the "tre protection system is ccamon to both units.
- ati"ication for Continued Coeration:
Th>
level in the fire tanka were a e t u r r.e d to normal w ' t 'a i n one houa aF.?-
the occur ence.
r t e n ryn u u d O L.b U 7008150 m