IR 05000275/1986006
| ML17083B733 | |
| Person / Time | |
|---|---|
| Site: | Diablo Canyon  |
| Issue date: | 04/18/1986 |
| From: | Hamada G, Yuhas G NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | |
| Shared Package | |
| ML17083B732 | List: |
| References | |
| 50-275-86-06, 50-275-86-6, 50-323-86-07, 50-323-86-7, NUDOCS 8605050529 | |
| Download: ML17083B733 (12) | |
Text
U. S.
NUCLEAR REGULATORY COMMISSION
REGION V
Report Nos. 50-275/86-06, 50-323/86-07 Docket Nos.'0-275, 50-323 License No. DPR-80, DPR-82 Licensee: Pacific Gas and Electric Company 77 Beale Street San Francisco, California 94106 li Facility Name:
Diablo Canyon Units 1 and, 2 Inspection at:
San Luis Obispo County, California Inspection conducted:
February 24-28, 1986 Inspector:
G. H.
da, Rad a ion Laboratory Specialist Date Signed Approved By:
G. P.
s, Chief Faciliti Radiological Protection Section Date Signed
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Ins ection of Februar 24-28, 1986 (Re ort Nos. 50-275/86-06, 50-323/86-07)
Areas Ins ected:
Routine announced inspection of radioactivity measurements program and associated quality assurance program.
This inspection involved the Region V Mobile Laboratory and covered modules 84725 and 79701.
Results:
No items of noncompliance or deviations were identified.
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Details 1.
Persons Contacted
'Boots, J.V., Manager, Chemistry and Radiation Protection-Chen, D., Engineer/Radiochemist,,
Chemistry and Radiation Protection Creath, M., Technician, Chemistry and Radiation Protection Guerra, F., Foreman, Chemistry
"Hinds, J.R.,
Power Production Engineer, Regulatory Compliance
>Johnson, R., Foreman, Radiochemistry
"-O'ara, W., Senior Chemistry and Radiation Protection Engineer 2.
-Indicates personnel present at exit interview.
I Discussion Split samples. of gases and liquids were obtained for confirmatory measurements.
For the charcoal. cartridge and filter paper sample categories, the"same samples were analyzed by both the licensee and the NRC.
The results are summarized below.
Table'
E ui ment Drain Li uid Diablo Nuclide uCi/ml NRC uCi/ml Ratio
~Diablo
"-Agreement R~aa e
Na-24 Mn-54 Co-57 Co-58 Co-60 I"131 3.28E-6 2.82E-5 3.25E-6 1.82E-3 2.77E-4 9.21E-6 3.10E-6 2.96E-5 2.59E-6 1.67E-3 2.56E-4 8.13E-6 1.06 0.95 1.25 1.09 1.08 1.13 0.50-2.00 0.75-1.33 0.50-2.00 0.85-1.18 0.80-1.25 0.60-1.66 See enclosure 'for explanation.
The sample indicated for Table 1 was selected to test a liquid matrix containing relatively low concentrations of radioactivity.
The ratios indicate that good agreement was achieved for this tes I N
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Table
RCS Stri ed Li uid Ratio Diablo NRC Diablo/
Agreement Nuclide uCi/ml uCi/ml NRC
~Ran e
Na-24 Co-58 I-131 I-132 I-133 I-134 I-135 Cs-138 5.86E-3 1.02E-3 3.96E-3 2.89E-3 3.95E-3 3.27E"3 2.94E-3 2.25E-2 6.50E-3 1.06E-3 4.22E-3 2.63E-3 4.90E-3 3.59E-3 3.90E-3 2.49E-2 0.90 0.96 0.94 1.10 0.81 0.91 0.75 0.90 0.80-1.25 0.80-3..25 0.85-1.18 0.80-1.25 0.80"1.25 0.75-1.33 0.75-1.33 0.75-1.33 The above test was for a liquid with relatively high concentrations of radioactivity.
While the agreement is adequate, there appears to be a
slight bias in the data.
Table
RCS Stri ed Gas Diablo Nuclide uCi/cc NRC uCi/cc Ratio Diablo/
NRC Agreement R~an e
Kr-85m Kr-87 Kr-88 Xe-133 Xe-133m Xe-135 2.87E-3 4.10E-3 5.72E-3 4.15E-2 8.85E-4 1.30E-2 2.58E-3 3.54E-3 5.68E-3 3.55E-2 1.03E-3 1.21E-2 Table
Waste Gas 1.11 1.16 1.01 1.17 0.86 1.07 0.80-1.25 0.75-1.33 0.80-1."25 0.85-1.18 0.60-1.66 0.80"1.25 Diablo
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NRC Nuclide uCi/cc uCi/cc Ratio Diablo/
Agreement NRC R~an e
Xe-133 1'.33E-2 1.16E-2 1.15 0.80-1.25 Tables 3 and 4 represent comparisons for a waste gas sample and fission gases'st'ripped from reactor coolant.
Adequate agreement was achieved for this category as indicated in the table ~
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Charcoal Cartrid e
Diablo Nuclide uCi/cc NRC uCi/cc Ratio Diablo/
NRC Agreement R~an a
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Br-82 I-131 I-133 1.65E-10 2.13E-10 0.77 0.75-1.33 5.91E-10 7.30E"10 0.81 0.80-1.25 8.68E-11 1.09E-10 0.80 0.75-1.33 The charcoal cartridge category shows adequate agreement but a small bias appears to be present,.
Table
Particulate Filter Diablo Nuclide uCi/cc NRC uCi/cc Ratio Diablo/
Agreement R~an a
Na-24
'Cr-51
, Mn-54 fe-59 Co-58
, Co-60 Sr-91 Zr-95 Zr-97 Nb-95
, I-131 Cs"134 Cs-136 Cs-137 Ba-140 I,a-140'a Be-7 5.01E-4 6.56E-5 4.64E-5 5.83E-6 1.13E-4 1.35E-5 7.84E-5 9.47E-6 1.01E-5'.26E-5 2.57E-6 3.30E-5 5.41E-6 5.42E-5 5.15E-5
'.40E-5 1'.25E-4 5.46E-4 6.41E-5 5.46E-5 6.59E-6 1.30E"4 1.50E-5 6.48E-5 1.14E-5 1.04E-5 1.44E-5 2.17E-6 3.16E-5 5.22E"6 5.72E-5 4.92E-5 4.40E-5 1.36E-4 0.92 1.02 0.85 0.88 0.87 0.90 1.21 0.83 0.97 0.88 1.18 1.04 1.04 0.95 1.05 1.00 0.92 0.80-1.25 0.80-1.25 0.80-1.25 0.75-1.33 0.85-1.18 0.80-1.25 0.60-1.66 0.75-1.33 0.60"1.66 0.80-1.25 0.60-,1.66 0.80-1.25 0.75"1.33 0.80-1.25 0.80-1.25 0.'80-1.25 0.80-1.25 Because an air particulate sample with 'sufficient activity to measure was difficult to obtain, a test for this geometry was performed by measuring a particulate filter sample obtained by filtering reactor coolant through a membrane filter.
This provided a sample with ample activity representing numerous nuclides.
The results indicate good agreement for this test:
The procedure used by counting technicians to evaluate and interpret data was reviewed.
During the course of this review, it was revealed that the technician had the option to reject results as not being "significant" when the sum of the counting error at the 95/ confidence limit (+1.96 sigma)
and the "critical level" (1.645 sigma) value exceeds the nuclide valu ~
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Note:
The sigma'above is the standard deviation for the net count.
This
'sigma is approximately equal to 2 times the standard deviation of background alone for low activity samples.
Thus the "critical level" when expressed in-terms of the standard deviation of background becomes approximately 2.33 background.
While this procedure provides high assurance that false positives are rejected, it also has a high probability of rejecting true positives.
This is inconsistent with accepted statistical practice and regulatory detection limit criteria.
When this 'inconsistency was pointed out, the licensee immediately changed the procedure to require that all values which exceed the 1.96 sigma limit be treated as positive values.
In conjunction with the above, a review of the method used by the system software to calculate sample standard deviation was performed.
A description of this procedure is contained in the document,
"Germanium Spectroscopy Analysis System Verification and Validation Report",
ll/23/83.
An incorrect formula for calculating sample standard is given in this document.
When the licensee was informed of this discrepancy, a
check was made to 'determine whether or not the software was generating the correct standard deviation term. It was concluded that the software was indeed performing the calculation correctly but the description of this process was incorrectly stated.
Diablo Canyon is in the process of acquiring a new gamma spectroscopy system with new software and expect to have this system operational by early summer. It is also expected that documentation of al1 phases of the new system, including software, will be available at that time.
What this means is that the new documents will supercede current documents including the above mentioned document.
A secondary chemistry review from the standpoint of facility and instrumentation was conducted.
A portion of the cold laboratory is currently shared with the hot laboratory.
A new secondary chemistry laboratory is currently under construction and is expected to be operational by October 1,
1986.
This new laboratory will not only provide more space, but more important; a cleaner environment, which is essential to performing trace analyses.
Instrumentation for trace analyses include the ion chromatograph and atomic absorption systems.
It is expected that addj.tional instrumentation will be acquired as needed.
3.
Exit Interview Inspection findings were discussed with licensee personnel indicated in paragraph l.
Expected'chedules for the new. cold chemistry laboratory and the new gamma spectroscopy system were discussed during this sessio I,
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Enclosure Criteria for Acce tin the Licensee's Measurements Resolution Ratio
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- 200 200 0.4 0.5 0.6 0.75 0.80 0.85 2.5
'.0 1.66 1.33 1.25 1.18 Com arison 1.
Divide each NRC result by.,its associated uncertainty to obtain the resolution.
(Note:
For purposes of this procedure, the uncertainty is defined as the relative standard deviation, one sigma, of the NRC result as calculated from counting statistics.)
2.
Divide each licensee result by the corresponding NRC result to obtain the ratio (licensee result/NRC).
3.
The licensee's measurement is in agreement if the value of the ratio falls within the limits shown in the preceding table for the corresponding resolutio p
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