ML20076K893
| ML20076K893 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 09/06/1983 |
| From: | Musolf D NORTHERN STATES POWER CO. |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.B.3, TASK-TM NUDOCS 8309150303 | |
| Download: ML20076K893 (6) | |
Text
{{#Wiki_filter:e + Northern States Power Company 414 Nicollet Mall Minneapoks. Minnesota 55401 Telephone (612) 330 5500 September 6, 1983 Director Office of Nuclear Reactor Regulation U S Nuclear Regulatory Commission Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Additional Clarification on NUREG-0737, Item II.B.3 Post Accident Sampling System Ref: Letter from D M Musolf, NSP, to Director of NRR, NRC, dated December 3,1982, titled "Information Related to NUREG-0737, Item II.B.3 Post Accident Sampling System". In our discussions with the NRC Staf f, several items relating to our post accident sampling system required further clarification: The purpose of this letter is to document the following information provided during these discussions: 1. NSP is a member of Westinghouse Owner's Group (WOG) committee on core damage analysis. 2. The interim procedures are in place for post accident sampling. The final procedures will be written, reviewed, and implemented when the WOG completes their program. l 3. A heat balance analysis was completed on our sample lines. The results showed that it would take 40 minutes to reach less than 10 degrees of the required temperature for a 200-foot long sample line. 4. The EG&G Inc letters (attached) state tha t the present arrangement of the sampling lines is adequate for obtaining a representative iodine sanple from containment during a post accident situation, if the line is heat traced from the containment to the condensing pot. We agree to heat trace this section of the sanple lines for each unit. A copy of the July 20, 1983 and August 29, 1983 letters from EC&G are attached. 5. A containment pressure curve as a function of time was requested l and is attached. It is Figure 14.9-2 from the USAR. 1 8309150303 830906 PDR ADOCK 05000282 \\ g P PDR
NORTHERN GTATED l*CWER COMPANY l l Dir of NRR Page 2 September 6,1983 We believe this information will allow the NRC Staff to complete their review of NUREG-0737 II.B.3. Please contact us if you have any questions related to this material, we David Musolf Managar-Nuclear Support Services DIN /SAF/j ls cc: Regional Administrator-III NRR Project Manager, NRC Resident Inspector, NRC G Charnoff July 20, 1983 letter from EG&G to NSP August 29, 1983 letter from EO&G to NSP Figure 14.9-2 in the USAR t ) l r ( I i l
II E G c G...... &4 P O cOX 1625. IDAHO F ALLS,loAMO 83415 July 20,1983 Mr. Don Schuelke Rural Route 2 Prairie Island Nuclear Plant Northern States Power Compar1y Welch, MN 55089 PRAIRIE ISLAND POST-ACCIDENT CONTAINMENT AIR SAMPLING SYSTEM REVIEW - DWA-17-83
Dear Sir:
As per your request, the EG&G staff has reviewed the adequacy of the post-accident containment sampling system (Design Change No. 82L688) that has been proposed for the Prairie Island Nuclear Plant. This review was directed principally at whether the system, as described, would provide representative measurable samples of the containment atinosphere in a post-accident environment. The conceptual design of the sampling system is in general adequate for sampling a post-accident enviroriment. However, some modifications are considered appropriate to this system to assure representative sampling. The following is a list of the conclusions and justifications that were ueveloped concerning this sampling system: 1. The sample line should be heat traced from the reactor containment to the steam collection device. It wa:, concluded that the distance of approximately fifty feet that the sample line travels outside the containment wall is too great to assure that condensation and plateout reactions would not remove a large fraction of activity present in the 3as stream. 2. The nitrogen purga gas should be introduced as far upstream in the sample line as possible (i.e., the containment boundary). This will prevent sample cross-contamination and reduce potential deposition in the sample line. 3. Some provision should be made for measuring the volume uf liquid collected in the condenser cell. Without a measure of the volume of liquid collected or some assurance that all waste drains to the sample vial, it would be difficult to determine the radionuclide concen-trations present in the containment.
^ Don Schuelhe Attachent 1 July 20, 1983 DWA-17-83 Page 2 4. No assurance is present that water will not be carried from the condenser pot into the gas sample line downstream to the gas analyzer. A simple condenser pot does not provide assurance that water carryover into the sample line will not occur. It is hoped that these comments will assist you in the design of your containment sampling system. If you have any further questions or if we can be of assistance, please call. Sincerely, Douglas W. Akers Radiation Measurements Section Physical & Biological Sciences Division af cc: R. W. Kiehn, EGSG Idaho l l \\ t ?
AttachmInt 2 gp6 $33 EGsG... ~. P.C. BOX 1625. IDAHO FALLS. IDAHO 83415 August 29, 1983 Mr. Joel Sorenson Rural Route 2 P,rairie Island Nuclear Plant Northern States Power Company Welch, MN 55089 PRAIRIE ISLAND POST-ACCIDENT CONTAINMENT AIR SAMPLING SYSTEM MODIFICATIONS - DWA-21-83
Dear Sir:
During our telephone conversation in early August, you indicated that changes were to be made in the post-accident monitoring system in response to our review letter (DWA-17-83). The principal change in the system design is to include heat tracing along the sample line to the steam collection device. This will provide greater assurance that plateout and condensation will not occur. Items 2-4 of the review letter were determined to be of much less concern based on your explanation of the system. For Item 2 it was determined that a three-minute purge using containment atmosphere was done prior to sampling and that the N2 purge gas is to be used only to clear the sample line after sampling. For Item 3, a calculational method is listed in the procedure which determines the containment atmosphere concentrations when used in conjunction with steam tables. This will provide assurance that the volume of water is measured as noted in the procedure. For Item 4, it was determined that the sampling device has a water jacket which should ensure proper condensation of the sample. It should again be noted that the evaluation performed on this sampling system is for the conceptual design only. This design does appear adequate to provide representative sampling with the added heat tracing system. Sincerely, I D. W. Akers Radiation Measurements af cc: R. W. Kiehn, EGaG Idaho l
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