ML20092A686
| ML20092A686 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 06/13/1984 |
| From: | William Jones OMAHA PUBLIC POWER DISTRICT |
| To: | John Miller Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.3, TASK-TM LIC-84-079, LIC-84-79, NUDOCS 8406190310 | |
| Download: ML20092A686 (5) | |
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Omaha Public Power District 1623 Harney Omaha. Nebraska 68102 402/536 4000 June 13, 1984 L IC-84-07 9 Mr. James R. Miller, Chief U. S. Nuclear Regulatory Commwion Office of Nuclear Regulatory Regulation Division of Licensing Operating Reactors Branch No. 3 Washi ngton, D.C.
20555 Refe rence: Docket No. 50-285
Dear Mr. Miller:
Post Accident Sampling System (NUREG-0737 - Item II.B.3)
In a telephone conversation on March 6,1984, the Omaha Public Power District discussed the Post Accident Sampling System (PASS) iacluding the problems be-ing experienced with the pH cell, the Ion Chrmatogra,'h, Gennanium detectors, and interim sampling capabilities with Mr. E. G. Tourigny of your staff.
Since this time, significant progress has been made toward the resolution of these problems.
This letter serves to provide an update on the status of the PASS, and to provide a new cmpletion date.
Items discussed as still being outstanding were:
(1) pH Cell As recommended by the manufacturer, a one-point calibration has been performed on the cell.
Additionally, the District has performed a two-point calibration.
Both calibrations have been rechecked. The elec-tronic portion of the calibration process still needs to be completed.
The plant staff will complete the electronic calibration and will check the 2-point calibration before declaring the pH cell operable.
(2) lon Chromatograph The connections for the Ion Chrmatograph have been moved fran Room 60 (the primary sample room) and have been placed in the corridor for eas-ier accessibility.
The Ion Chrmatograph has been laboratory tested using the NRC matrix solution including the addition of trisodium phos-phate dodecahydrate (TSP), and successful results have been achieved.
The District now plans to test the Ion Chromatograph using the connec-tions provided in the corridor to take a sample from the system.
If the results of these field tests prove to be satisfactory, the Ion Chro:aatograph can be declared operable.
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Mr. James R. Miller, Chief June 13, 1984 Page Two (3)
Germanium Detectors The District had experienced problems with the Gemanium detectors.
The detectors have functioned from time to time, but in general have not been dependable. The vendor was to the site four times trying to resolve the drift problem, and has stated it is due to the temperature and humidity of the environment in the area.
The detectors have been tested in the chemistry lab and operated satisfactorily; (the lab is air-condi tioned).
In order to detennine if it was indeed a temperature and humidity problem, the District built a temporary air-conditioned en-closure around one of the detectors.
In this way, the temperature and humidity of the District's environment closely approximated that of the lab. Preliminary results, over the past 2 months, indicate this seems to have alleviated the problem. However, the detector outside the air-conditioned enclosure has also functioned properly.
The District will continue to monitor the operation of these detectors.
If further re-sults indicate the problems were due to temperature and humidity, the District will pursue permanent corrective action in this area.
Based on recent successful results, however, this portion of the system can be considered operable.
(4)
Interim Sampling Capabilities
-The current interim sr.piing and analysis capabilities for boron and chloride are presented in the attachment to this letter.
It should be
- noted that these capabilities do not meet (nor is it intended that they meet) the NRC guidance for primary sampling capabilities, but describe the District's ability as far as back-up capabilities are concerned.
Because some testing which must be completed before the system is declared operational cannot be done during shutdown, the District proposes a new date of 30 days after reaching 10D% pwer for system operability. The Post Acci-dent Sampling System Technical Specifications required by NUREG-0737 will also be submitted at that time.
Si el y,
bbtM W. C. Jc nes Divisibji Manager Product' ion Operations WCJ/DJM/ rh-J Attachment-cc:
LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Avenue, N.W.
Washington, D.C.
20036 Mr. E. G. Tourigny, Project Manager Mr. L. A. Yandell, Senior Resident Inspector
s ATTACHMENT Interim Sampling and Analysis Capabilities for Boron and Chloride A.
'The current 524 cc sample flask car.not be handled two (2) hours after an accident if the flask contains undiluted reactor coolant. This is
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based on the fact that the dose rates to the technicians would exceed the GDC-19 guidelines during handling and analysis.
The sample must be diluted if it is to be. analyzed two (2) hours after an accident.
The dilution factor is' based on the accuracy of the gross gamma detectors which each have an accuracy of f 20%.
Thus, the over-all accuracy due to dilution, detection and analysis is + 80%, - 50%.
Radiation exposure calculations were performed to evaluate the use of the current flask containing undiluted reactor coolant within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> af ter an accident.
The dose rate on contact was calculated to be 1.08 x 105 R/hr.
To reduce this exposure, the sample must be diluted by a factor of 380 in order to keep exposure below GDC-19 guidelines. This assumes the technician is. handling and analyzing the flask for 2 min-
-utes contact and 20 minutes otherwise. This dilution factor does not consider ^the error introduced by the gross gamma detectors (i 20%).
Because-the dilution factor is proportional to_ the measurements derived from the detectors, the overall dilution error is + 50%, - 33%.
There-fore, to canpensate for this error, the dilution _ factor must be adjust-ed to 510 to_ ensure the dose rate is within GDC-19 guidelines.
(See Table 1).
B.
Chloride Analysis Handling of the current 524 cc sample flask for chloride analysis 96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br /> after an accident cannot be done if the flask contains undiluted reactor coolant. -(This is due to GDC-19 concerns).
As with the Boron analysis, the sample must be diluted before analysis. Again, this dilution is dependent upon the accuracy of the gross gamma detectors (i 20%) yielding an overall analysis accuracy (including dilution and detection errors) of + 80%, - 50%.
Radiation exposure calculations were performed to evaluate the consequences of using the 524 cc flask 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> af ter an accident. The dose rate on contact was calculated
-to be 1.1 x 104 R/hr.
Upon review, it was _ concluded that a dilution factor of 67 is required to keep the dose rate below GDC-19 guidelines 100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> after an acci-dent.
This assumes the technician is handling the sample for 2 minutes contact and 15 minutes otherwise.
This dilution factor is unacceptable due to the low detection level re-commended by the NRC for chloride analysis (0.075 ppm). Dilution by a factor of 67 would lead to a detection level belcw 75 ppb. The Dis-trict's equipment does not have this sensitivity with accurate or repro-ducible results.
B.
Chloride Analysis (Continced)
If, however, the sample was allowed to decay for 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br />, a dilution factor of 5.4 would be sufficient to reduce the exposure..This dilu-tion yields acceptable results for low level detection as shown in Table _I.
Allowing the sample to decay 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> can be justified as follows.
Chloride analysis would essentially be necessary following a depressur-ized (large-break) LOCA.
During a pressurized LOCA there is little or no chance of internal or external contamination of the reactor coolant systea leading to chloride build-up.
The detection of chloride follow-ing a large-break LOCA (100 hours0.00116 days <br />0.0278 hours <br />1.653439e-4 weeks <br />3.805e-5 months <br /> or.1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> after the event) is to provide an indication of whether or not the potential for corrosion exists. Within a 100-hour or 1000-hour time frame, attempting to re-duce the potential for corrosion is an insignificant task in comparison to the event itself. Therefore, the District believes utilizing a 1000-hour decay time is adequate (and preferable) for meeting NRC guid-ance for backup chloride sampling and analysis capabilities.
t h
t t
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-Table I
. Analysis Boron Chloride Decay Time, hrs 2
100 1000 Volume Dilution Factor, cc 510 67 5.4 Accuracy (Includes i 20% error
~+ 8 0%
+ 8 0%
+ 80%
_ for Gross Gamma Detectars)
_5 0%
- 5 0%
- 50%
Minimum Sample ~ Concentration, ppm 1020(2).
5 0.4 Lower Detection Level Using Lab Equipment,.inxn 2-0.075 0.075 Whole Body Ddse,~R(1) 2,. 9 5.0
3.9 NOTES
- 1) Dose rates could vary; a safety factor of 2 was used when calculating the exposure.
- 2) A minimum sarple concentration of 1020 ppm is acceptable since the concentration of boron will be >2000.ppn fol-lowing boron _ injection. (Reference USAR Table 9.2-2)
Additionally, excore detectors can be utilized to verify subcriticality.
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