ML20107B731
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February 8, 1973 C. A. Pelletier, &ief, Environmental Inspection Br.
Directorate of Regulatory Operations, Headquarters HIGH I-131 REI. EASE RATE - OYSTER CREEK This memo is forwarded for Headquarters' action. On January 29, 1973,
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I was notified by telephone by the New Jersey Department of Environmental i
Protection, which performs environ-w al measurements under the AEC/NJ j
State contract, that one of their air samplers in the environs of Oyster Creek had indicated unusually high I-131 concentrations. The sampler is located approximately 1-1/2 miles to the southeast of the Oyster Creek i
j Nuclear Power Plant. The sampling time was from January 9 through 16, l
1973. The observed concentration averaged over the period of approximately 3
5-1/2 days was 127 femtocuries per cubic meter.
(The ape for I-131 in the unrestricted area after applying a reconcentration factor of 700 is l
143 femtocuries per cubic meter.) The State personnel indicated that this j
concentration was approximately a factor of 10 to 20 times higher than that normally observed.
I spoke to plant personnel on January 31, 1973, and they supplied the i
following information. he plant was started up on January 10 and was
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i critical at approximately 7:30 a.m.
The plant was at full power by January 13, 1973. The charcoal cartridge from the stack monitor was placed in service on.Nuary 10 at 8:00 a.m. and was removed and analyzed on January 13 at 10:35 a.m.
Analysis of the cartridge indicated an average l
release rate for this period of 2.1 microcuries per second. Normal releases have been running approximately 0.1 to 0.2 microcuries per second. Plant personnel stated that the concentrations on the particulate
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filter, the radioactive noble gas concentrations, and the reactor water iodine concentrations had not been unusual during this period. Plant
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I personnel also indicated that they hadn't seen an iodine " spike" like this during previous startups. A charcoal cartridge placed in service for a 24-hour period subsequent to the removal of the aforementioned l
cartridge indicated that the release rate was down by a factor of 10 (in the normal range). We meteorological conditions for the period in question were such that the wind blev toward the southeast with an average wind speed l
of approximately 14 mi ha per hour. Oyster Creek's Technical Specification 3.6.8.2 states that the. d== release rate shall not exceed 4 microcuries 4
per second. Technical Specification 4.6.B(1)(g) states that in the event the iodine release rate exceeds 4% of the above 1;ait that the charcoal cartridge in th's stack monitor shall be pulled and anelyzed twice a week.
Based on the above, Oyster Creek is meeting its Technical Specification requirements.
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. i Using the release rate and the meteorological conditions existing at the time of the release, I calculated the concentration which might have j
been observed in the e m irons had the sampler been located'at the ideal location for finding the highest eonsentration. 7he calculations indi-i cated that the concentration observed by State personnel might have been exceeded by up to perhaps a factor of 5.
This indicates that on a short time average, the 10 CFR 20 limits reduced by a factor of 700, may be exceeded occasionally. However, on an annual basis they should certainly l
not be exceeded.
The following is our analysis of the situation. Since it involves piecing together bits of information, we re&21:e that it is subject to question.
i Based primarily on the time sequence involved and the findings during l
l C. Pelletier's study at Oyster Creek, we think the most likely cause of 1
the iodine spike would have been the running of the mechanical vacuum pump for several hours during initial startup. A likely source might have been iodine which had plated out on condenser tubes during normal operations and subsequently became available for release. We and the licensee think there is a possibility that the release limit of 4 microcuries per second may have been exceeded for a time shorter than the three-day sampling i
period which was observed by the charcoal cartridge.
Questions arising as a result of this exercise, for which we request some i
R0:HQ consnents, are:
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Was there any intent to allow the licensee to average his iodine release rate over o certain period of time, perhaps as long as three or four days? The three or four day period seems to be implied by Technical Specification 4.6.B(1)(g) which states that 4
damples shall be taken twice a week if the licensee is running l
release rates greater than 47. of limits, i
i 2.
Are we on firm ground in asking the licensee to change and analyze his charcoal cartridges on a more frequent basis during the next startup to help identify the source of, and mechanism for, iodine activity being released to the stack, as we think he should? (This has been discussed with the licenses, and he is agreeable to doing this if he can still average his release over three or four days for the purpose of detemining compliance with the Technical Specification release rate limit.)
I 3.
If the licensee does change the cartridge more frequently, say daily, and upon analysis, the results indicate that the release rate has exceeded 4 microcuries per second, where does he stand then with respect to violating the Technical Specifications? May he simply include the high results for that one day with results for several days and time average over half a week, or must he report the high result as a violation of thelimiting condition for operation?
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4 Oyster Creek does not have an iodina monitor, as such, which would l
provide a readdut in real time of the concentration going out the j
stack as one would have for the noble gases via the stack gas j
Vermont Yankee has an iodine monitor which looks at a monitor.
i fixed sharcoal cartridge, although the usefulness of such a monitor i
with a high noble gas background is subject to some question.
j However, the question arises as to whether we should push Oyster j
Creek to incorporate such an iodine monitor in their stack monitoring system. We bring enforcement estion to bear upon a licenses who i
enseeds his off-gas release rate, although if averaged over several i
hours, he may have been within his Technical Specification release i
limit. Are the iodine release rate limits of less significance than the off-gas release rate limits?
i 5.
There is also some question as to the significance of the licensee exceeding a release rate limit for a few hours if the limit was
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based on annual average conditions and if averaged over a period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> the limit was not exe wded.
(20.106 allows concentrations of effluents to unrestricted ares to be averaged over a period of l
j As one criterion for 24-hour notification, 20.403 j
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up to one year.
i allows averaging over a period of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of concentrations at a level of 500 times the limits specified in 10 CFR 20. As one criterion for i
a 30-day report, 20.405 specifies concentrations in unrestricted areas have to be in axesse of 10 times any applicable limits set forth in j
this part or in the licensee's license.)
e Although we are waiting for Headquarters' guidance in this matter, our interim position is that for subsequent startups in similar situations, thio licensee should change the charcoal cartridge in the stack monitor on a more frequent i
basis than twice a week. We think that the cartridge should be changed l
before and after the mechanical vacuum pump goes into operation during the next startup to help identify the source of the activity. The licensee is l
agreeable to doing this but would not like to be placed in the embarrcosing 4
position of establishing that he is violating a Technical Specification i
through his cooperation with us on this matter.
If our mobile van was avail-l able, this is an instance in which it probably would have been used.
l We consider the above to be a generic problem. To make Technical Specifica-tions covering this area more readily inspectable, we recommend that release 4
rate limits be either identified an instantaneous limits thereby requiring a real time monitor; or if they are not instantaneous release rate limits, i
l the period of time over which the release may be everaged should be designated, and the surveillance requirements in the Technical Specifications should be d
set at a frequency matching the time over which the release may be averaged.
We' await your comment on these matters.
J. P. Stohr, Senior Environmental Protection &
Special Programs Section cc:
J. G. Keppler, RO:HQ i
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