ML20148F815
| ML20148F815 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 03/16/1988 |
| From: | Larson C NORTHERN STATES POWER CO. |
| To: | Norelius C NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| NUDOCS 8803280292 | |
| Download: ML20148F815 (2) | |
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Northern States Power Company 114 N+ col'et Man Minneapons. Minnesota 55401, March 16, 1988 Tewpwet2) 330 ssoo pgicay7y pgg77C 1
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Mr Charles E Norelius, Director lJ W d-Division of Reactor Projects C N k-U S Nuclear Regulatory Commission Region III fR y
799 Roosevelt Road Glen Ellyn, Illinois 60137 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License No. DPR 42 50-306 DPR-60 Additional Information Related to Startup Physics Program
Reference:
Letter dated December 31, 1987 from Charles E Norelius, NRC Region III, to C E Larson, NSP The purpose of this letter is to provide additional information re-lated to the adequacy of corrective actions taken in response to Vio-lation No. 2 in NRC degion III Inspection Reports 50-282/87012 and 50-306/87011.
This additional information was requested in your letter of December 31, 1987.
Frequency of Actual Power versus Indicat'.on Power Measurements During power escalation, comparisons between the actual versus indi-cared power are made at several different power levels.
Comparisons start at a point where the system is stable up through full power.
Calorimetric measurements are performed at 20%, 35%, 60%, 90%, and 100% power.
In addition, the reactor power as measured by loop delta T is compared to the nuclear instrumentation system measured power during the escalation to full power.
A direct measurement of actual power versus indicated power is not possible during heatup.
Inaccuracies in Calculated Neutron Leakage The prediction of excore detector responses were developed to give a
general indication of expected response only. While our model gives a general idea of the relative response from cycle to cycle, it has sev-eral limitations in that it does not explicitly model such factors as downcomer boron concentration and temperature, i
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.'. hs i-Mr Charles E Norelius Northern States Power Company March 16, 1987 Page 2 By necessity, this model must make assumptions concerning the position of the control rods, which may or may not be valid when the excore responses are calibrated.
We are in the process of benchmarking this modeling technique to de-termine if uncertainties can be reduced.
We believe that some model improvements can be made relatively easily to better predict excore detector response.
These efforts will be completed prior to the re-start from the next Unit No. 1 refueling outage this autumn.
Please contact us if you have any questions related to the additional information we have provided, f
M8M C E Larson Vice President Nuclear Generation c: Regional Administrator, Region III, NRC Sr Resident Inspector, NRC Sr Project Manager, NRC G Charnoif l
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