ML19322D866
| ML19322D866 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 11/09/1979 |
| From: | Abbott E Advisory Committee on Reactor Safeguards |
| To: | |
| References | |
| ACRS-SM-0168, ACRS-SM-168, NUDOCS 8003060027 | |
| Download: ML19322D866 (2) | |
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INDICATION OF CORE DAMAGE DURING THE TMI ACCIDENT BY Edward G. Abbott Reviewing the accident's sequence of events from WUKHHiOO shaus there were ntanerous indications of core damage. The indications for fission product release were: 1) reactor coolant samples, 2) effluent radiation monitors, 3) process and area radiation monitors, 4) radiation surveys. Also, excessive fuel cladding temperatures, ICS loop temperature and the sudden increase in the RB pressure indicated core damage.
For the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the accident 20 effluent, 5 process, and 10 area radiation nonitor alarms were received. Continuing increases in activ-ity level were also noted. Seven radiation surveys were made some of which had readings of 71000 R/h. Four reactor coolant samples were taken and three had levels of activity that could not be attributed to a crud burst.
Hot leg RTD's were 720 F and reactor pressure was 1600 psig l
(T 605 F). Voiding and steam generations in the core indicated core sat damage was imminent or had already occurred. Incore thermocouple readings ranged frca 80 F to 2620 F.
Althot:3h this was less than the temperature at which the clad melts, it was high enough for a zi c-water reaction.
In addition, the reactor building pressure spike indicated hydrogen was gen-erated by the above reaction and subsequently burned.
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,r 4 M y once during the sequence of events in the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> is l
M en the shift supervisor notified the
" fuel Failure" mentioned.
Pennsylvania Emergency Management Agency, he reports " failed fuel and For the next nine hours there is no mention a anall offsite release."
of core dan""Je in the sequence of events.
It simply W e NRC's emphasis in NCREG-0600 is on " procedures."
compares the action of 'IMI's management and operators with the require-ments and steps of their procedures. We report fails to recognize that in the 'IMI accident the existing procedures were inadequate for the mis criticism applies equally to the 'IMI management plant's condition.
mis is perhaps the reason the indication of core during the accident.
damage were not interpreted as core danage during the initial phase of the accident.
Failure to recognize, take appropriate action and report in response-to these conditions should have been addressed more directly in NUREG-0600.
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