ML19221A626
| ML19221A626 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/07/1979 |
| From: | Thiesing J INDUSTRY ADVISORY GROUP |
| To: | Levenson M INDUSTRY ADVISORY GROUP |
| References | |
| TASK-107, NUDOCS 7905230468 | |
| Download: ML19221A626 (2) | |
Text
go jf f km M-lf A
(.
5.h s.,y.
TO:
Hilt Levenson DATE:
4/7/79
SUBJECT:
Containment FROM:
J.W.
Thiesin COPIES:
J.
Hurley 0F:
THI-IAG The following are some observations and estimates concerning the containment building and an estimate of the lower bound for total metal-water reaction.
I.
Operating History During Incident A.
Simulate H burn (1400, 3-28-79) to determine magnitude 2
of burn and confirm spray operation.
Determine pressure and temperature transient during H2 burn.
L B.
More definitive containment pressure data is needed.
Based on plot provided showing a 28 psig peak pressure, a burn of approx. 250 lb coles Hg would be required, equivalent to a 27% Zr-H O reaction consumed in the burn.
2 The burn would create a short term superheat in containment of (+1000 degrees F).
Spray actuation would reduce super-heat to zero in about 1 minute.
(operator log on 3-28-79 (1350) indicates that spray actuation occurred im plyir$g a peak pressure of at least the 30 psig spray set point.
Contain-ment H2 at the time would have been 4.7% H2, assunming all H
""8 CU"8"
'd*
2 II.
Current Status A.
Containment H in now at about 2 V/O corresponding to a 2
Zr-H O reaction of about 11.5%. (Thus metal water reaction 2
was greater than 27% + 11.5% = 38.51).
3 bubble in the RCS at 280 degrees F
- (Also note that a 1000 ft and 1000 psig would correspond to an additional 13% Zr-H,0 reaction, and the saturated H30 i'n RCS corresponds to an' additional 2.5% Zr-H O reaction for a grand total estimate 2
of at least 54%
Zr-H O Reaction 166 079 2
O 7 905 23 0 9'd y
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+
4
/-. Containment
/'I Page Two
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4/7/79
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s, 5 $,
g B.
Current building pressure holding at about
(
and'50 degroos F.
1.0 psig j
i 1.
Continued negative pressure probably inplies some g
inward buckling of the linor plate duo to trapped r
air behind the liner and inleakage through flud head welds and hatch liners and seals to the area behind the liner plate.
Recommend maintenance of current status to prevent leakage of containment inventory to environment.
Any potential future liner problems could be solved by allowing containment pressure to rise to - 0.1 psig but accuracy of containment pressure conitors and potential barometric pressure swings mitigate against this.
C.
Current containment leakage area, and rate of outleakage function of positive pressure, could be estimated by
,as a careful simulation of current operating modo, and system and containment parameters.
s III. Future Disposition of Containment A.
Reduction of PCS temperature will increase ability to maintain negative pressure in containment as will cessation of venting through pressurizer relief block valve.
B.
Increase in service water temperature as decrease ability to maintain negativesummer approgches will pressure.
C.
Maintenance of negative pressure over a long period will increase containment non-condensible gas inventory due to inleakage, and thus reduce ability to maintain negative pressure.
Also, as the non-condensible gas inventory rises, the negative pressure inducing efficiency of the air coolers decreases due to the relative inefficiency of reducing air temperature compared to reducing humidity by condensation.
D.
Should the reactor coolant system be forced into the feed and dump mode again, the containment can accommodate the current heat load at a steady-state temperature of about 200 degrees F (about 10-20 psig) forever with only one air cooler running.
With all S coo.lers running, the steady-state tenperature would be about 130 degrees F, maybe 1-3 psig.
(note:
steaming rate for current decay heat load is 40 gpm)
I Pressure rise with only one cooler running is very slow, re-sulting in a pressure of 6.5 psig at one day.
166 080