ML20081L688
| ML20081L688 | |
| Person / Time | |
|---|---|
| Site: | Washington State University |
| Issue date: | 03/23/1995 |
| From: | Tripard G WASHINGTON STATE UNIV., PULLMAN, WA |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 9503300295 | |
| Download: ML20081L688 (4) | |
Text
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Nudear Radiahon Center Pullman.WA 99164-1300 509 335-8641 FAX S09-335-4433' Thursday, March 23,1995 Director
. Office of Nuclear Reactor Regulation USNRC B ~ Washington, D.C. 20555 L
L 1 Ref: Docket 50-27 * '
Facility Operating License No. R-76
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Dear Sir:
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" On the moming of March 17,1995 in response to recent Radiation Safety Office and City of Pullman concerns about sewer releases of radioactive isotopes, the reactor supervisor (Jerry Neidiger) and I.were reviewing water releases from our hold-up tanks. I noted that the last sewer release on January 11,1995 was slightly above the new 10 CFR 20 release limits. We checked with our Technical Specifications [6.10 (1) (a) in particular) and verified that "any accidental E release of radioactivity above permissible limits in unrestricted areas whether or not the release -
L resulted in property damage, personal injury, or exposure" constitutes a reportable occurrence. I therefore called and faxed both the Regional Office of the US NRC and the US NRC Operations g Center.to report the incident at about 2 pm, March 17,1995 (see enclosed memo).
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Our Regional Administrator accepted the call, asked a few appropriate questions and said to write the incident up in detail. He then said that they would review the incident at the next inspection.
The amount of radioactivity involved is 3.69 micro-Ci mixed in 3181-cubic feet of water. I do not know at this time the source of this activity. We are quite sure it did not originate from our reactor pool because such activity has a recognizable gamma-ray signature which did not appear in 'our .
- Ge(Li) detector scan of a sample of the water. The following is a record of recent releases:
Total Activity Concentration - Dilution Concentration Release Date pCi before dil. pCi/ml factor after dil.pCi/ml 1/5/93 7.2 9.27E-08 0.214 1.98378E-08 3/1063 10.4 18.lE-08 0.204 3.6822E-08 4/20 S 3 2.04 11.0E-08 1 11.E-08 5/1863 10.5 30.4E-08 0.097 2.9488E-08 7/13S3 29.2 15.3E-08 0.201 3.0753E-08 8/30 S 3 14.3 72.4E-08 0.272 19.693E-08 10/25 S 3 2.9 10.9E-08 0.326 3.5534E-08 11/16S3 0.21 4.01E-08 0.104 0.4170E-08
<- new regs begin -
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2/3S4 0.98 3.44E-08 0.243 0.83592E-08 I 3/23 S 4 ' 0.68 - 7.41E-08 0.235 1.74135E-08 4/21S 4 0.96 4.44E-08 0.26 1.1544E-08 6/17S4- 0.46 3.47E-08 0.165 0.57255E-08 .
12/8S 4 ' O.89 -
- 3.26E-08 -0.303 0.98778E-08 "i 1/1ISS - 3.69: 16.5E-08 0.248 4.092E-08 <-- violation 9503300295 950323 -
PDR. ADOCK 05000027 '
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The following is a histogram of the last column above, showing the 1/11/95 release above the new 10 CFR 20 release limit of 2 x 10-8 Ci/ml:
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Recent Sewer Release Concentrations 20 --
18 -- 1993 1994 16 --
l l 1995 y ja .. l l e 12 -- l l
?10-- l l , ,
~2 8--
6--
. .4--
2- - - - - - - - - - - - -
New i0 CFR 20 0-releam N Releases Current Status of the event analysis:
This week is a particularly bad time to try to analyze this event. It is the campus school break and most of us are on a reduced schedule or absent. The reactor technician who did the release left on vacationjust before the violation was discovered and will not be back until March 27,1995. What we believe may have happened is as follows:
After July of 1993 the Radiation Safety Office quit dumping some of their radioactive wastes down the drain of their waste collection shed in the back of the building because its drain goes into our hold-up tanks so that we were double counting the facility releases. After they stopped doing this, the activity found in our hold up tanks dropped dramatically. During the 1994 we had no incidents of these formerly large activities.
- In the weeks just prior to the January 1995 release there wem several unusual water releases to the hold-up tank; a large boiler room release associated with furnace problems, a radioactive chemistry lab (room 101) heater leak into the floor drain, a large water release from the Radiation Safety Office storage shed at the back of the building to clean used scintillator fluid jugs. Any of these releases may have been large enough in volume to have dislodged some old accumulations of contamination that could have collected m the drain system during the years prior to 1994 when larger activities were routinely released into the radioactive drains.
. This should still have not been a problem because even with the slightly elevated activity we have been able to achieve dilution factors of 10 in the past which would have brought us well under the limit. Unfortunately our reactor technician improper', set up the dilution system and instead of the exaected factor of 10 he instead achieved a dilution factor of only four. Jerry Neidiger and I be'.ieve the primary mistake made in the setting was that a pump had been left on that should have been left off during the eductor operation. I cannot confirm this until the technician gets back from vacation. The other possibility is that one of the valves (used to control the degme of dilution) may not have been set properly.
. We actually may not have exceeded the release limit of the campus. There is a funher dilution of any release from our facility when our release is combined with sewer water from the rest of
1 campus. I can not estimate the value of the daily release of the campus right now because the engin,eer who knows this number is on vacation until M. rch 27,1995. Our release was spread over a three day period.
Proposed actions to reduce the likelyhood of a similar event happening in the future:
. We can not fully resolve the issues in this event until more information is gathered. IfI can confirm that the problem was indeed caused by a pump being left on inappropriately then I need to question the technician carefully as to why this happened. The solution may be as simple as putting an extra line of instruction in the appropriate procedure that says one needs to confm' n that the recirculation pump is not on before making a release to the sewer.
If you have any questions, please contact Dr. Gerald Tripard, Facility Director (509) 335-0172 Sincerely, - , -
Gerald E. Tripard, Director enclosure: Initial memo by Jerry .'Teidiger, sent by FAX to US NRC on March 17,1995 cc: Region V NRC office
I STATE UNIVERSITY
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' Nuclear Radiation Center,. Pullman, Washington 99164-1300/509-335-8641 ]
MEMORANDUM TO. : DR. GERALD TRIPARD, DIRECTOR ,
FROM' : JERRY A. NEIDIGER, REACTOR SUPERVISOR DATE : MARCH 17, 1995 SUBJECT : DISCHARGE OF LIQUID WASTE EXCEEDING 10 CFR 20 LIMITS On January 11, the facility's liquid waste tank was sampled, analyzed and discharged to the sewer system as per our SOP #11 Since the calculated activity of the tank contents was 1.
wcsgreaterthanthe10CFR20limitof2.0x10~g5x10~9 uci/ml*which uCi/ml, the Reactor Technician discharged the waste tank using the educetor dilution cystem. The educator system gives an average dilution factor of 0.25 which would still yield an average discharge concentration of 4.2x10~8 uCi/ml, still greater than the 10 CFR 20 limit. Thinking he could achieve a larger dilution factor by throttling the tank discharge valve, he opened the tank discharge only one turn (fully open is 5-6 turns) and preceded to disc.arge the liquid waste tank to the sewer system. Upon completion of the discharge, the diluted activity'was calculated and discovered the partial openigg of the tank valve DID NOT increase the dilution factor. 1.g5x10~ uCi/ml tank contents concentration was'releasgd in 3181 Ft of water to yield a discharge concentration of 4.2x10~ uCi/ml and a total release of 3.69 uCi. The dilution factor was calcu) '.ed to still be 0.2483. ;
.I became aware of the results of this discharge on January 13th when I questioned why it was ta).ing so long to dump the liquid waste and the discharge final results. I immediately obtained a 500 m1 sample of the remaining liquid waste from the tank and counted it on a GeLi
. system to identif the isotopes present in the sample. The counting results showed gamma peaks or levels above normal background water camples. I ma e a note in the discharge log that the isotope may be a pure beta emitter which would be counted on the low background proportional counter but not the GeLi system.
I must apologize for not informing you immediately about the liquid discharge above 10 CFR 20 limits. I neglected to realize the significance of this occurrence until we were reveiwing our liquid waste discharge limits.
One final note is that this concentration activity DOES NOT take into account the dilution factor from the rest of campus OR the city of Pullman, although I have no data as to what that would be.
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