ML20090B412
| ML20090B412 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 03/01/1982 |
| From: | Laaksonen J Office of Nuclear Reactor Regulation |
| To: | Sheron B Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML082380335 | List:
|
| References | |
| FOIA-91-106 NUDOCS 8203110426 | |
| Download: ML20090B412 (2) | |
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MAR 01 1982 NEMJRANDUH FOR: Brian-W. Sheron, Acting Chief Reactor Syste:ms Branch, DSI TilRU:
Cerald Hazetis, Section Leader, Section C. RSB, DSI FROH:
Jukka t.aaksonen, Section C, Reactor Systems Branch, 051
SUBJECT:
GINNA SG TUBE RUPTURE EVENT For your inforation, I had an opportunity to discuss the Ginna SG tube rup-ture event with Westinghouse representatives who are responsible for develop-ing generic emergency response guidelines for Westinghouse plants. The dis-cussions took place February 9,1982.
From the discussion I learned that Westinghouse has available detailed primary and secondary parameters from the very beginning of the event. The information has been extracted from the computer printouts and the parameters were plotted with about one minute intervals. The parameters included at least following:
1 Temperature in the core exit.
2)))
Temperature in both cold legs 3
Tanperature in pressurizer (unclear in which part of the psi)
Temperature in the upper head 4)g Pressure in the reactor coolant syttem S
- 6) Pressure in both steam generators The following observatici s could be made from the curves:
1.
The secondary pressures were equal and had decreased to about 800 psi at the time the mptured SG was isolated. Westinghouse explained that the pressure decrease was attributed to the cold auxiliary feedwater.
As soon as_ the mptured SG B was cogletely isolated the pressure started to increase and was about 900 psi at 10:07 when the-operator started to depressurize the RCS to the same pressure.
The RCS pressure decreased too low (800 psi) becadse the operator cotid 2.
not close the PORY. The intent was to stop dapressurization at 900 psi.
The stuck open P0RV caus,d also the pressurizer to fill with relatively cold water and nomal prasure control was lost.
-3.
Westinghouse explanation on the history of steam bubble in the upper head is-that the bubble was formed at 10:08, af ter the PORY had stuck open. The bubble persisted until the operators started the RCP in loop A.
Westinghouse has diagnosed the existence of the bubbla by coccaring the upper head and pressurizer temperatures. This comparison indicates that from 10:08 to 11:29 the upper head was the hottest part l
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Westinghouse position is that the operators should have taminated the $1 when told to inspite of the bubble. A note will be added to the SG tube tvpture guidelines which tells not to wrry about a possi-ble steam bubble in the upper head at that time because.it will be condensed whan one RCP is started.
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