ML19221A464
| ML19221A464 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 03/28/1979 |
| From: | Metropolitan Edison Co |
| To: | |
| References | |
| OLS-790328, NUDOCS 7905230046 | |
| Download: ML19221A464 (3) | |
Text
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CHRONOLOGY OF TMl-2 ACCIDENT UNTIL CORE COOLING RESTORED 9,
_ _. WEDNESDAY MARCH 28. 1979 FIGURE TIME EVENT 1
4:00 & 36 sec loss of Condensate Pump Loss of Feedwater 4: 00 + 37 sec Turbine Trip 1
Electromatic relief valve opens (2255 3-6 sec psig) to relieve pressure in RCS 1
9-12 sec Reactor trip on high pressure (2355 psig) 1 12-15 sec RCS pressure decays to 2205 psig (POV should have closed) 2
+15 see RCS hot leg temperature peaks at 611.1 F and 610.9 F (pressure of 2150 psig, 450 psig over saturation) 2146.9 psig 10
+30 see Event recorder shows 2A and 2B started at same time as turbine trip.
Pressure started up at +30 sec 164 460 sec Pressurizer level indication begins to rise 3&6
+1 min it appears that the Steam Generators A and B are essentially dry 4
2 min & 2 sec ECCS initiation (HPI) at 1650 psig 4
4-12 min Pressurizer level of f scale - one HP! pump (PIC) tripped at
+ 4 min 38 sec.
Second HPI pump (PIA) tripped at + 10 min 24 sec 12
+6 min RCS flashes as pressure bottoms out at 1350 psi (Hot leg temperature of 584 F) 4 6 nin Pressurizer level indication is off scale high
?9052300'l) 163 045
2 FIGURE TIME EVENT
+7 min 29 sec Reactor building sump pump on 10
+8 min Aux, feedxater flow is initiated by opening closed valves 4&5 11 min 43 sec (Makeup Pump PI A (ECCS flow HPI) re-started by operators 8 min 18 sec
_B Steam Generator pressure reached minimum.
8 min 21 see A steam generator pressure started to recover af ter that
+15 min RC Drain Tank diaphragm ruptures at 190 psig due to continued-discharge thru electromatic relief valve.
11 73 min Operator trips RC pumps in loop B
(Pump vibration and reduction and os-cillation in loop flow had been observed).
__ll
_1 _r 40 min ~
Operator trips RC. pumps in Loop A h
(Pump vibration and reduction and os-cillation in loop flow had been observed).
14
+1.8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (est)
CORE BEGINS HEAT UP TRANSIENT - Hot leg temperature begins to rise to 620 F (off scale) and cold leg temperature begins to drop to 150 F (HPl water)
+2.3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> (est)
POV (we believe this is pressurizer power operated relief valve) isolated by operator af ter S.G.-B isolated to prevent leakage 19
+3 hour RCS pressure increases to 2150 psi and electromatic relief valve opened 18 3.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> RC Drain Tank pressure spike of 5 psi 18
+3.8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> RC Drain tank pressure spike of 11 psi (unexplained) - RCS pressure only 1750; Containment pressure increases from 1 to 3 psi i63 046 E
L -
3 FIGURE TIME EVENT 15
+5 hour Peak containment pressure of 4.5 psis containment would be automatically isolated at 4 psig.
We F.lieve the containment had been manually iso;*ted prior to this time.
19
+5.3 to 6.! hour RCS pressure increased f ro.a 1250 psi to 2!00 psi 19 7.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> Operator opens electromatic relief valve to depressurize RCS to attempt initiation of RHR at 400 psi 19
+8-9 hour RCS pressure decreases to 500-450 psi; CFT discharge 15
+9.9 hour1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> 28 'si containment pressure spike, sprays initiated and stopped af ter 5000 gal. of NaOH injected (abou t 2 minutes of operation) 19
+13.5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> Electromatic relief valve closed to repressurize RCS, collapse voids and start RC pump 19
+13.5-16 hour RCS pressure increased from 650 psi to 2300 psi 14
+16 hour RC pump in Loop A started hot leg temperature decreases to 560 F and cold leg temperature increases to 400 F indicating flow.
163 047
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