ML20101G014

Responds to NRC 920408 Request for Addl Info Re Time Required to Obtain Reactor Coolant Grab Sample & Analyze Sample for Dissolved Gas.Util Negotiating Agreement to Analyze Gas,Per NUREG-0737,Item II.B.3

ML20101G014
Person / Time
Site:	Fort Calhoun
Issue date:	06/12/1992
From:	Gates W OMAHA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.3, TASK-TM LIC-92-197R, TAC-M81256, NUDOCS 9206250257
Download: ML20101G014 (4)

Text

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Omaha Public Power District 444 South 16th Street Mall Omaha, Nebraska 68102-2247 402/636-2000 June 12, 1992 LIC-92-197R U.S. Nuclear Regulators Commission Attn: Document Control Desk

, Main Station PI-137 Washington, DC 20555

References:

1. Docket No. 50-285

2. Letter from OPPD (W. G. Gales) to NRC (Document Control

. Desk) dated July 30, 1991 (LIC-91-177R)

3. Letter from NRC (D. M. Crutchfield) to Chairman - Advanced Light Water Reactor Steering Committee (E. E. Kintner) dated February 27,1992. " Major Technical and Policy issues Concerning the Evolutionary And Passive Plant Designs"

4. Letter from NRC (D. L. Wigginton) to OPPD (W. G. bates) dated April 8, 1992 Gentlemen:

SUBJECT:

NRC Information Request Regarding Post Accident Sampling System (PASS) - Fort Calhoun Station (FCS), Unit 1 (TAC No M81256) x Omaha Public Power District (0 PPD) is providing this letter in response to the.

. NRC's request (Reference 4) for additional information on the time needed to

{ obtain a reactor coolant (RC) grab sample and analyze it for dissolved gas.

In a telephone call on May 11, 1992, Mr, T. C. Matthews of my staff .s Mr.S.D.BloomoftheNRCandreceiveda30dayextensiontoallow0gokewith .PD to u

perform additional research prior to submitting this response. In Reference 2, OPPD proposed to delete credit for the PASS automatic inline dissolved gas analysis sequence and retain only the ability to obtain an undiluted, pressurized RC grab sample for offsite dissolved gas analysis. The NRC request for additional information is stated below:

NRC RE0 VEST Criterion 1 in Item II.B.3 of NUREG-0737 specifies that the licensee should have the capability to obtain reactor coolant samples and containment atmosphere samples and perform analysis within 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> of a decision to obtain them. Either confirm that the Fort Calhoun Station's modified procedure for dissolved gas analysis, based on taking grab samples, meets this requirement, or indicate how much time is expected to pass between the decision to take the sample and the completion of the analysis. Justify the acceptability of a time greater than 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.

OD 4s st24  % i yment with Equal opgrten 920625b2'57 920612 "'*l*

PDR ADOCK 05000285 k P PDR

V. S. Nuclear Regulatory Commission LIC-92-197R Page 2 OPPD RESPONSE As stated in Reference 2 OPPD does not have the ability to analyze undiluted, pressurizedRCgrabsamplesonsiteandcurrentlydoesnothavepre-arranged agreements for offsite analysis. The nearest facility capable of analyzing an undiluted, pressurized RC grab sample for dissolved gases is the Department' of Energy's (DOE) Argonne National Laboratory (ANL) in Argonne, Illinois. ANL representatives have estimated that following notification, it would take 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> to set up the initial test equipment / shielding and have results from the first sample analysis. Upon receipt by ANL, subsecuent samples could be analyzed in 3 to 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Use of prebuilt specialized test equipment to decrease the set-up time for analysis of the initial RC grab sample is not considered practical by ANL.

A hypothetical timeline (Attachment A) was developed, which assumes that the decision to take a grab sample is made 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> after the beginning of an accident and ANL is notified at that time. The grab sample is then actually taken at 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the accident. This sample time is based on Reference 3, page 30, which concluded that samples for dissolved gas and chloride analysis can be taken up to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> after the beginning of an accident. The grab sample would then be trucked to ANL, and the results would be available approximately 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> after the sample was taken (54 hours6.25e-4 days <br />0.015 hours <br />8.928571e-5 weeks <br />2.0547e-5 months <br /> into the accident).

Less time would be necessary to analyze subsequent grab samples as the initial ANL test equipment setup would be reused. Following analysis of the first grab sample, the sample container would be trucked back to FCS where anotl.er sample could then be taken, shipped, and analyzed. As shown on Attachment A, the estimated time to receive analysis results for subsequent samples is 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> after the sample is taken at FCS. A total of 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br /> is estimated between the results of eacc subsequent analysis.

Criteilon (8) of NVREG 0737 Item II.B.3 states that the equipment available l for back up grab sample analysis shall provide results at least once per day for 7 days following an accident and then at least once per week. OPPD's utilization of ANL for offsite grab sample dissolved gas analysis does not meet the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> fr.quency of Criterion The initial grab sample results would take 54 hours6.25e-4 days <br />0.015 hours <br />8.928571e-5 weeks <br />2.0547e-5 months <br /> with subsequent analy(8). sis results available approximately every 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />. Although the specific sample analysis frequency of NUREG 0737 Item II.B.3 would not be met by this process, it would provide confirmatory I

analysis information to assess the accident severity.

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U. S. Nuclear Regulatory Commission LIC-92-197R Page 3 OPPD considers the above noted analysis timeframes justified since information obtained from RC dissolved gas sample analysis is useful only to confirm the extent of core damage and not for accident mitigation. However, isoto>ic analysis of diluted RC grab samples through operation of the PASS can 1elp evaluate core damage. Safety related, real time instrumentation to monitor fuel failure is available to the operators and Technical Support Center personnel for use in accident mitigation. This instrumentation includes the core exit thermocouples, heated junction thermocouples, containment radiation monitors and containment atmosphere hydrogen monitors. Details of this justification are available in Reference 2.

OPPD is negotiating a formal agreement with the DOE to utilize the ANL hot cell facilities for post-accident dissolved gas analysis of RC grab samples.

Th;s agreement, when reflected in appropriate FCS procedures, will provide a process which meets the intent of NUREG 0737 Item II.B.3. If this approach is acceptable to the NRC, these actions will be completed on a schedule to be coordinated with the NRC Project Manager for FCS.

If you should have any questions, please contact me. i Sincerely, C. Eh .

J. G. Gates Division Manager Nuclear Operations WGG/sel Attachment c: LeBoeuf, Lamb, Leiby & MacRae .

R. D. Martin, NRC Regional Administrator, Region IV R. P. Mullikin, NRC Senior Resident Inspector S. D. Bloom, NRC Acting Project Manager

Attachment A LIC-92-197R Time-line for Obtainina PASS RC Grab Samole Dissolved Gas Analysit A postulated time line for obtaining the initial grab sample following an accident is as follows:

• Accident Occurs at "T" Hours e At 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> into the accident it is determined that a RC grab sample will be taken for dissolved gas analytis. At this time, ANL and a qualified trucker would be notified. The PASS would determine certain radionuclides in the RC and the activity level of a grab sample. This information would be used in radioactivity calculations to meet . Federal regulations for shipping the grab sample as well as for analysis preparation at ANL.

• At 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the accident a grab sample is taken using container SL-19. The basis of taking a sample at this time is the NRC staff comment in Reference 3.

• The grab sample is loaded onto the truck at "T" plus 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br />, e The grab sample is delivered to ANL at "T" plus 39 hours4.513889e-4 days <br />0.0108 hours <br />6.448413e-5 weeks <br />1.48395e-5 months <br />, e ANL dissolved gas analysis results available at "T" plus 54 hours6.25e-4 days <br />0.015 hours <br />8.928571e-5 weeks <br />2.0547e-5 months <br /> (30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> after the sample was taken).

Subsequent actions to obtain additional sample analysis results would occur as follows:

• ANL grab sample analysis complete at "S" hours e load container SL-19 onto truck at ANL, "S" plus 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />

• Truck arrives at Fort Calhoun Station, "S" plus 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> e Unload and reconnect for new sample, "S" plus 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> e Grab sample taken, "S" plus 17 hours1.967593e-4 days <br />0.00472 hours <br />2.810847e-5 weeks <br />6.4685e-6 months <br />

• Prepare and load container SL-19, "S" plus 19 hours2.199074e-4 days <br />0.00528 hours <br />3.141534e-5 weeks <br />7.2295e-6 months <br />

• Truck arrives at ANL, "S" plus 31 hours3.587963e-4 days <br />0.00861 hours <br />5.125661e-5 weeks <br />1.17955e-5 months <br />

• Unload container SL-19, conduct dissolved gss analysis and have results available, "S" plus 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br /> (20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br /> after sample was taken).

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