ML17345B285
| ML17345B285 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 09/26/1983 |
| From: | Heltemes C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Harold Denton, Deyoung R, Minogue R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE), Office of Nuclear Reactor Regulation, NRC OFFICE OF NUCLEAR REGULATORY RESEARCH (RES) |
| Shared Package | |
| ML17345B286 | List: |
| References | |
| NUDOCS 8310060171 | |
| Download: ML17345B285 (4) | |
Text
tlENORANDUI) FOR:
Harold R. Denton, Director Office of lluclear Reactor Regulation Richard C. DeYoung, Director Office of Inspection and Enforcement Robert B. IHnogue, Director Office of Nuclear Regulatory Research James P. O'Reilly, Regional Administrator Region II FROM:
C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data
SUBJECT:
CASE STUDY REPORT -
LOW TEMPERATURE OVERPRESSURE EVENTS AT TURKEY POINT UNIT 4
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'a.(A, On November 28 and 29, 1981 during the filling and venting process
<<hil'e restarting the reactor after a refuel-ing outage, two overpressure events occurred at Turkey Point Unit 4 within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> which exceeded by a factor of two the technical specification limits.
Both trains of the overpressure protection system we'e inoperable and operator actions were required to mitigate the pressure transients 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 lost 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 NRC 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, AEOD performed a detailed case study of the event sequences, the causes and the corrective actions
- taken, and the generic implications of the events.
A preliminary report of our investigation is enclosed.
In accordance with AEOD's "peer review" process, prior to the finalization and distribution of our case study reports, we are providing NRR, IE, RES, Region II, NSAC, INPO and the licensee with a copy of a preliminary report for review and comment, particularly regarding accuracy and completeness of the technical details.
Changes to the findings, conclusions, and recomrIen-dations will be considered only if the underlying information concerning the details of plant design,
'systems operation or sequence of events is in error.
Therefore, comments are heing solicited on the technical accuracy of the report.
The findings,. conclusions and recommendations are provided for your FICE SURNAME/
DATE 1n orma 1or
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NRC FORM 318 (10-80) NRCM 0240 OFFICIAL RECORD COPY USOPO: 1981~5-960
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Since we wish to finalize and issue the report shortly, we ask that any comments be received by us within 30 days from receipt of the preliminary copy.
Should your office require some additional time beyond that point, please let us know, otherwise it will be assmed that there are no comments.
He are also placing a copy of the preliminary r eport in the Public Document Roan. If you or your staff have any questions regarding this matter, please contact Wayne Lanning of my staff.
Hr. Lanning can be reached at 301/492-4433.
Encl osur e:
As stated C. J. Heltemes, Jr., Director Office for Analysis and Evaluation of Operational Data cc:
w/enclosure R. J. lIattson, NRR D. G. Eisenhut, NRR R. H. Yollmer, NRR T. Speis, NRR H. L. Thompson, NRR G.
M. Rivenbark, NRR
- 0. D. Parr, NRR J. S. Wermiel, NRR F. D. Cofiman, NRR J. H. glor, IE E. L. Jordan, IE S. A. Schwartz, IE R. H. Bernero, RES C. E. Johnson, RES P. Holmes-Ray, RII IE Training Center T. t1urley, RI J. Keppler, RIII J. Collins, RIV J. Hartin, RV
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