ML17345B287

Forwards,For Review & Comment, Low Temp Overpressure Events at Turkey Point Unit 4, Draft Case Study Rept

ML17345B287
Person / Time
Site:	Turkey Point
Issue date:	09/26/1983
From:	Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD)
To:	Wilkinson E INSTITUTE OF NUCLEAR POWER OPERATIONS
Shared Package
ML17345B286	List: ML17345B285 ML17345B287 ML17345B288 ML17345B289 ML17345B290 ML17345B291 ML17345B292
References
NUDOCS 8310060175
Download: ML17345B287 (4)

Text

tlr. Eugene P. Wilkinson President Institute of Nuclear Power Operations 1100 Circle 75 Parkway, Suite 1500

Atlanta, GA 30339

Subject:

Case Study Report - Low Temperature Overpressure Events At Turkey Point Unit 4 On November 28 and 29, 1981 during the filling and venting process while restarting the reactor after a refueling outage, two overpressure events occurred at Turkey Point Unit 4 which exceeded by a factor of two the technical specification limits.

Both trains of the overpressure protection system were inoperable and operator actions were required to mitigate the pressure t~ansients to prevent a more severe pressure excursion.

The safety significance of the events is the possibility of the reactor vessel failure by brittle fracture as a consequence of the overpressure transients during low temperature operation..

These overpressurization transients were the first events to occur at an operating pressurized water reactor which exceeded the technical specification limits since the IIRC staff resolved the generic issue of low temperature overpressure transients in 1979.

The events were identified to Congress as Abnormal Occurrences which indicate that the events involved a major reduction in the degree of protection to the public health and safety.

Because of the safety significance of the

events, AEOO performed a detailed case study of the event sequences, the causes and the corrective actions taken, and the generic impl-ications of the events.

A preliminary report of our investigation is enclosed.

The purpose of this letter is to provide you with the opportunity to review the repor t, particularly with regard to its completeness and accuracy, prior to the issuance of the AEOD final report.

Changes to the findings, con-clusions and recommendations will be considered only if the underlying information concerning the details of plant design, systems operation or event sequence is in error.

Therefore, counts are being solicited on the technical accuracy of the report.

The findings, conclusions, and recommen-dations are provided for your information in order that you understand the significance AEOD places on this event and therefore obtain a more complete picture of the total report.

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You will note that there fs an activity identiffed for Il!PO to consider developing a Recommended Operating Practice for pressurized water reactors concerning filling and venting of the reactor coolant system.

We would appreciate your specific comments on the issue and whether INPO may be receptive to pursuing this activity.

We would welcome your comments..either informally by phone or formally by letter.

Since we wish to finalize and i.ssue the report shortly, we ask that any comments you may wish to make be brought to our attention within 30 days from receipt of this letter.

As you may know, AEOD reports do not represent an official WRC position or the position of the responsible HRC program office.

Our reports are one input to an ongoing review and evaluation process, and any recommendation contained fn our final report will be considered and perhaps modified or eliminated by the responsible HRC office.

A copy of the preliminary report and this letter are being placed fn the Public Document Roon at 1717 H Street, W.W., 1!ashfngton, D.C.

20555.

If you have any questions regarding this matter, please feel free to contact Wayne Lannfng of my staff.

51r. Lanning can be reached at 301/492-4433.

Sincerely,

Enclosure:

As stated C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data

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