ML19224A721
| ML19224A721 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 04/26/1979 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Crocker H, Galen Smith NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| NUDOCS 7905300112 | |
| Download: ML19224A721 (5) | |
Text
s
~
- f. / '.N*f WIl VDiff {f. Hf9 q
(k C...._..
J g. _..
W
~ ~ ~
5 hk l
~
~
l i
i -
4
./
T/*ff
/
,/
a
)
7905300117.-
+
16Y057 y
i 4
m Question 3.
The exposure received by the employees who were in the plant at the time of the cool.ing system malfunction and the way in which employee exposure is measured and recorded; Answer Employees working in radiation areas wore self-reading dosintters and thermoluminescent dosimeters {TLDs).
TLDs are usually read on a quarterly basis unless the self-i
~
reading dosimeters. indicate a significant exposure.
No significant exposures occt.rred as a direct result of the cooling system malfunction, however, through April 16 the following exposures of licensee or contractor personnel were received during recovery operations:
Dose Range (Whole Body Gamma)
Number in Range 100 - 250 mrem 125 251 - 500 mrem 35 501 - 750 mrem 10 751 - 1000 mrem 4
1001 - 2000 mrem 3
2001 - 3000 mrem 0
3001 - 4000 mrem 3
/
y/
)
167 058 e
'4F
5-----.......---...-.-
w.
Question 5.
The cause, as far as may be determined, of the March 28 and 30 radiation leaks; During the initial stages of tha event on March 28, large Anwer quantif.ics of water were released from the primary coolant system into t.he reactor containment building cump. This water contained xenon and iodinc from the cor c.
Sump, pumps
~
in the containment building automatically pumped this water into tanks in the Auxiliary Building.
Because of the large quantity of water involved, the holding tanks overficwed onto the floor of the Auxiliary Building.
Xenon and Iodine evolved from this watar and was released via the Auxiliary Building Ventilation systenn.
wA In addition, radioactive gases were relcased frnm theg-gas
~
handling system.
The exact release mechanism is not precisely known at this time.
'i.
e 1
t?.
e
.~
.d u
. 47
.):
'm,5
.~1 e.c i.
.Er es.
m
..m.
167 059
.e
- E r:
T 3.-
.e q.
. q__________----_~.-
\\
\\
t.
Question 6.
The radiation Tevels measured at all distances prior to the March 28 incident as well as subsequent to it and the potential health hazard posed by those 1cvals; Ans'ver Prior to the March 28 incident the normal background level in all directions from the site ranged from approximately j
.01.02 milli roentgens / hour.
In the t.ime frame iraT>ediately
{
following the. incident, the measured radiatian levels were j
substantially higher with the highest readings bc,g peasured
}
i near the site boundary.
i At the time of the incident. Metropolitan Edison had 17 thermoluminescent dosimeters (TLDs) deployed at various distances from the site (out to approximately 15 miles).
These TLDs measure the integrated dose over a period of time.
The TLDs were collected and replaced with new TLDs approximately 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> after the incident.
Analysis of the TI.Ds indicated that the average dose rate in the envirens
~
(as measured by the TL0s) during the thirty hours inr.ediately after the incident was generally in the range 0.1-0.2, milliroentgens/ hour above background.
Two locations on uninhabited islands near the site indicated a significantly higher dose rate.
Shelley Island (1.1 miles SSW of site) - 1.3 milliroentgens/hr Vohr Island (0.4 miles NNW of site) - 25 milliroentgens/hr nuring t pa iod March 29-31, analysis of the results from the same TLDr indicated that the dose rate was generally ir. the range of 0.02-0.2 millirnentgan/hr.
The highest reading was O.8 mi'llircentgen/hr 1/2 mile EflE of the site.
The dose rate
~
at Shelley Island and Kohg Island had decreased to 0.3 and 1.0
'2-milliror.ntgens/hr respectively.
167 060 c
O
s
. =,
2 Analysis of the 37 TLDs deployed by the NRC out to 12 c1iles from t e sity indicated that the average dose rates on March 31-April 1 ' ranged from.05-0.1 millf roentgens /hr with the highest average dose rate pf 1,4 ist111rcentgens/hr approximately 1/2 mile ENE of the $lte.
During the next week the average dose rates were on a gen ~erally downward trend ar.d by April 8 they were at normal background levels.
No significant. health hazard is expected to result from the
- incident at Three Mile Island.
e 9
e e
e e
9 e
e 4
e O
e e
o e
e e
~
167 061
.