ML20076D585
| ML20076D585 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/17/1983 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | Stolz J Office of Nuclear Reactor Regulation |
| References | |
| 5211-83-220, NUDOCS 8308230451 | |
| Download: ML20076D585 (2) | |
Text
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GPU Nuclear Corporation g
gf Post Office Box 480 Route 441 South Middletown, Pennsylvania 17057-0191 717 944 7621 TELEX 84-2386 Writer's Direct Dial Number:
August 17, 1983 5211-83-220 Office of Nuclear Reactor Regulation Attn:
J. F.'Stolz, Chief Operating Reactors Branch No. 4 Division of Licensing U. S. Nuclear Regulatory Commission Washington, D.C.
20555
Dear Sir:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. DPR-50 Docket No. 50-289 RPS Instrumentation Accuracies This letter is to notify you that GPUN has been informed by Babcock & Wilcox (B&W) that there has been a loss of traceability between original equipment test data and the summary test reports supporting Topical Report BAW 10003 which addresses RPS instrument errors and provides the basis of the FSAR analyses.
Consequently, B&W has performed retesting of certain modules employing updated IEEE testing methods and new calculational methods of combining module errors into instrument string errors. This reassessment resulted in certain errors larger than those previously used in safety analyses for TMI-1.
Based upon previous plant-specific analyses performed for other B&W 177 Fuel Assembly plants, application of the new calculated errors could result in certain RPS setpoint limits more conservative than the current TMI-l settings, although the differences would be small.
In light of the above, we are currently reviewing the information received from B&W and are pursuing a more detailed evaluation of the RPS instrument accuracies.
In the interim, as a prudent measure, we will administratively limit RPS setpoints to values that are consistent with bounding calculations j
received from L&W that are based on worst-case instrument string errors determined previously for other 177 FA plants.
The limits affected, and their respective interim administrative limits, are:
Current RPS Interim Setpoint Admin. Limit 1.
Overpower Trip 105.5%
104.9%
2.
Flux Flow Trip 108%
107%
3.
Hi RCS Temp Trip 619 F 618 F 8308230451 830817 DR ADOCK 05000289 OOf PDR GPU Nuclear Corporation is a subsidiary of the General Public Utilities Corporation
.. L c.
Mr. J. F. Stolz 5211-83-220 We anticipate that the detailed evaluation of RPS instrument errors for TMI-l will be completed in March,1984. At that time, we will determine if technical specification changes are appropriate and will notify the NRC accordingly.
Sincerely, r
11.
. Ilukill Director, TMI-l llDil:LWil: vj f cc:
R. Conte J. Van Vliet J. Allen