IR 05000312/1979013
| ML19253B245 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 08/07/1979 |
| From: | Book H, Thomas R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML19253B242 | List: |
| References | |
| 50-312-79-13, NUDOCS 7910030723 | |
| Download: ML19253B245 (4) | |
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U. s. NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMEhT
REGION V
Report No.
50-312 Docket No.
ttcon,, go, DPR-54 safeguards croup Licensee:
Sacramento flunicipal Utility District P. O. Box 15830 Sacramento, California 95813 Facility Na:re:
P,ancho Seco Inspection at:
Clay Station, California Inspection conducted:
June 13-14, 1979,
&/ M/bW 7/f/7f Inspectors:
R. D. Thomas, Radiation Specialist
' Dat-Signed Date Signed Date Signed Approved By (M -
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e H. E. Book, Chief, Fuel Facility ~ and Materials Safety D te Signed
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Branch Surrma ry :
Inspection on June 13-14,1979 (Report fio. 50-312/79-13)
~ Areas Inspected: Analytical results and sampling techniques were examined pertinent to the confirmatory measurements program.
Representatives from the DOE Radiological and Environmental Sciences Laboratory reviewed the overall program for possible areas of disagreement and sources of error in the reported analytical values.
Independent inspection effort related to a reported contaminated algae sample. The inspection involved 12 inspector hours onsite by one flRC inspector and two DOE-RESL representatives.
Results: Some sampling and counting techniques were identified which could be sources of error in the analytical results related to the confirmatory measurements program.
Corrective actions were proposed.
fio items of noncompliance or deviations were. identified.
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DETAILS 1.
Persons Contacted R. Colombo, Technical Assistant R. Miller, Chemical and Radiation Protection Supervisor W. Wilson, Senior Chemical and Radiation Assistant T. Morrill, Senior Chemical and Radiation Assistant B. Rogers, Senior Chemical and Radiation Assistant Others D. Olson, Chief, Radiochemistry Section, DOE, Radiological and Environmental Sciences Laboratory S. Morton, Radiochemistry Sectiori, DOE, Radiological and Environmental Sciences Laboratory 2.
Confirmatory Measurements Proaran At the request of the inspector, tuo individuals from the Radiochemistry Section of the DOE Radiological and Environmental Sciences Laboratory (RESL)
accompanied the inspector to Rancho Seco on June 13-14, 1979 to find a way of resolving the differences between RESL and the licensee's analytical results in the confirmatory measurenents samples (see Paragraph 4.d.,
IE Inspection Report 50-312/79-06).
a.
Gamma Spectrometer Countinq Efficiencies Two standar'd counting sources, supplied by RESL, were used to verify the counting efficiencies for a 50 milliliter liquid source at three centimeters and a point source at 20 centimeters from the detector.
Agreement was within 5% except for the 122 kev gamma ray of Co-58 which was high by 8%.
Since the licensee did not have a calibration for a point source, a comparison was made using the efficiency for a two inch distributed source.
At three and ten centimeters an expected disagreement was noted because of the different geometry configurations.
When the counting data were corrected for the effects of dissimilar calibration, the data results appeared to be well within the classification of agreement.
b.
Gamma Ray Branchino Ratios An examination was made of the gamma spectrometer computer library for gamma ray branching ratios being used by the licensee.
In many cases, different gamma ray branching ratios are being used by RESL and the licensee. Two cases of importance were Xe-133 where the difference
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-2-was 7% and of Ba-140 where the difference was about 40%.
This situation has been corrected since a copy of the latest tables of nuclear data, as contained in ORNL/NUREG/TM-102, dated August 1977 was supplied to the licensee.
The licensee stated that the computer library would bp changed to incorporate the current nuclear data.
c.
Calibration of Gas Countina Containers
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A discussion with the licensee indicated that the gas counting containers were being calibrated with an aqueous standard, and no attempt is being made to correct for absorption of the gammas in the water natrix. Calculations showed that the licensee's results would be high by about 35%, which would account for most of the differences between the DOE-RESL and the licensee's gas analyses results. The licensee stated that an effort would be made to obtain a Xe-127 gas standard from the National Bureau of Standards which could be used to calibrate their normal gas counting containers.
A discussion was held related to the loss of gas from a gas sample during transit to the RESL. To resolve this situation, it was agreed that the next gas sample taken would be counted by the licensee, sent to RESL for analysis, and returned to the licensee for a followup count.
d.
Splittino of liouid Samoles The technique for splitting liquid samples was examined.
It was determined that the proba' ility of obtaining identical samples, using o
the present splitting technique, was quite low. The licensee has not been using the recommended sample splitting technique which could account for the differences in the liquid sample analyses. The licensee agreed to follow the written sample splitting procedure which was supplied by RESL. The licensee also agreed to supply, with each analysis of gross beta in liquid samples, a statement concerning the radioisotope used for calibration. To minimize the possibility of additional errors in the analytical data results, RESL and the licensee agreed that all sample data would be decay corrected to the sampling date.
3.
Summary The two DOE-RESL representatives summarized their findings with R. Miller, Chemical and Radiation Protection Supervisor, and T. I'.orrill, Senior Chemical and Radiation Assistant.
All corrective actions and agreements were discussed. The inspector stated that a new series of confirmatory measurement samples would be taken on the next inspection.
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Contaninated Algae Sample It was brought to the attention of the inspecter, while onsite, that a mixed effluent algae sample collected on May 15, 1979 showed five (5)
radionuclides which slightly exceeded the ShUD trip notification limits.
A discussion with the licensee indicated that follow-up actions were being taken to determine the source of contamination in the plant liquid effluent.
On Wednesday, June 20, 1979, SMUD nade a news release solving the " mystery" of the contaminated algae sample. Apparently, the algae sample was cross contaninated by a plastic bag which had been used inside the plant to transport contaminated protective clothing. An analysis of a plastic bag similar to the one used to collect the algae sample for May indicated the same contaminants in the same trace quantities that were present in the May algae sample.
On June 21, 1979, an NRC inspector obtained an algae sample from Clay Creek for an independent measurenent. At the time of this report, the analytical results were not available. The results will be reported in a subsequent inspection report.
(Followupitem 79-13-01)
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