ML19241B326
| ML19241B326 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/05/1979 |
| From: | Jerome Murphy NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| To: | Ybarrondo L EG&G, INC. |
| References | |
| NUDOCS 7907160092 | |
| Download: ML19241B326 (2) | |
Text
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(h ucph3 4,0 sq 2-t 317 Potential Core 'telt Sequence of
' Events Based on TM1 Conditions on April 4.1979 I
I l
1.
Best technical judgment--core melt will not occur.
2 If core melt occurs--best technical judgment on sequence of events.
Time = 0
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--All reactor core flow stops with system at 2500 psi.
containment cooling starts soon.
t Time = 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> j":i 1
--Mol ten core mel ts through reactor vessel and El falls into water in bottom of containment.
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--Containment pressure goes to 23 psi.
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--Do not expect simultaneous hydrogen burning. but if l g occurred, containment pressure could go up to about 90 psi.
f Time = 3 days
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5,
--Molten core penetrating containment basemat--now about 3-4 feet into basemat.
Time = 1 week
--If there had been no_ containment cooling at all, predict containment failure by steam overpressure.
t Expected Final Condition Containment. remains intact core mass reaches thermal equilibrium af ter penetrating about halfway through the containment basemat, no significant release to environment.
i Important Notes fal W 7
1.
Containment sprays and heat removal are required to prevent containment failure.
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2.
Steam explosions and hydrogen explosions may occur but not expected' to rupture containment.
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Buhl Dra f t POTENTI AL CCRC l'ELT SCENARIO AT T!!!
BASED ON CONDITIONS OF 4/4/79 Assu:nptf ans in analysis: primary coolant pu:ip fails. High pressure cociant
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injection operates to fill vessel. Pressure increases to 2500 psia. High pressure coolant assuned to fail. The t'ime of high pressure coolant failure e
is seven days followin9 reactor trip and is time 0 in the accident scenario (q-described.
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Core fielt Times
[;f Time Cctranent It O
High Pressure Coolant Stops t
28 hrs Core uncovers l
29 fielting Starts 1
30 hrs 10 min.
Core falls into plenum 30 hrs 15 min.
Lower head fails
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Containment Parameters AT 77/g posw r.
Pressure without Pressure with Depth of Concrete Case Time Pydrogen Burning Hydrogen Burning Penetration Coments (psia)
(psia)
(cm)
Containment Cooling Operates 30 hrs 15 n.in.
23 63 0
If sprays operate, release 47 hrs 24 91 92 category PWR 7; if sprays 64 hrs 27 88 M6 fail, release category PWR 6 Sprays Operate, 30 hrs 15 min.
29 95 0
Predict containment failure no cooling of 47 hrs 37 83 147 by over pressure at 169 hrs containment 64 hrs 43 55 178 release category,PWR 7 hestase d? PD.tStGIUTY OF OW2M/9ecs.5Md RNMet* ds' <2WrA%vktq WC X2f'oMMKNb fADV/J/CN3 F#A A FUTWRED (ENfof COWTNWML<ff J^// M
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