ML19308B702
| ML19308B702 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/31/1979 |
| From: | Harold Denton Office of Nuclear Reactor Regulation |
| To: | Deyoumg R NRC - NRC THREE MILE ISLAND TASK FORCE |
| Shared Package | |
| ML19308B703 | List: |
| References | |
| TASK-TF, TASK-TMR NTFTM-790724-02, NTFTM-790724-2, NUDOCS 8001160767 | |
| Download: ML19308B702 (2) | |
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UNITED STA S NUCLEAR REGULATORY COMMISSIO
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,E WASHINGTON, D. C. 20555
,e AUG 311979 Q
Ref No: NTFTM 790724-02 MEMORANDUM FOR:
Richard C. DeYoung, Deputy Staff Director NRC/TMI Special Inquiry Group FROM:
Harold R. Denton, Director Office of Nuclear Reactor Regulation
SUBJECT:
PRECURSOR EVENT IN A FOREIGN REACTOR By memorandum dated July 24, 1979, you requesced that we forward to you all relevant information currently available to NRR concerning an event involving a small LOCA at a foreign reactor, viz., a stuck-open PORV at a Swiss reactor.
In particular, you requested the following information as a minimum:
1.
A description of who within the NRC became aware of this event, by what means nas knowledge of this event formally or informally received by the NRC, and when was knowledge of the event acquired.
2.
A discussion of the basis for any decisions that have been made concerning the safety significance of this event and its applica-bility to domestic reactors.
3.
A discussion of the regulatory requirements associated with the reporting of this event to the NRC by the vendor, both after and prior to the TMI accident.
4.
A discussion of the basis for any decisions to release to the public information associated with this event.
These items are addressed individually below.
Item 1 As indicated in Enclosure 1, knowledge of this event was obtained in a meeting with Westinghouse on April 26, 1979. The event was informally mentioned by Westinghouse representatives in response to a question by an NRC representative (A.Thadani). is the meeting summary of the April 26, 1979 meeting which noted (page 5) the stuck-open PORY without identifying the reactor. As a result of this meeting, follow-up action was initiated by the NRC to obtain addi-tional details.
Subsequently, two formal proprietary reports describing the event were obtained from the Swiss Government, and these reports have been sent to the Special Inquiry Group.
Also, Westinghouse brief-ly noted this event in a letter, T. M. Anderson to D. Ross dated May 1,1979.
(Enclosure 2, page 1 of the attachment.)
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AUG 311979 R ' chard C. DeYaung I tem 2 As also indicated in Enclosure 1, this event was considered to have safety significance and applicability to domestic reactors. Although the event involves a Westinghouse-designed reactor, it is similar to the TMI-2 accident in that it involves a reactor transient with a stuck-open PORV, and some of the same instrumentation trends and system characteristics were observed. Further, the event was significant in that it confirmed other information on the existence of a deficiency in the ECCS actuation logic for Westinghouse-designed reactors. NRC Bulletins 79-06 and 79-06A had previously (April 11 and April 13, 1979) requested actions to correct this deficiency.
Item 3 The subject of whether regulatory requirements required the reporting of this event to the NRC, either before or after the TMI-2 accident, is under study by the Office of Inspection and Enforcement (IE).
I suggest that direct coninunications be established with IE (H. Thornburg) regarding the timing and results of their investigation.
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'% cwc [oR I tem 4 Discussions with the Swiss Government, and the arrangements reached regarding public discussion of this event have been handled by the Office of International Programs (IP).
IP representatives met with Mr. Rogovin and others of the Special Inquiry Group on July 31, 1979, and explained fully the manner and conditions under which the reports were provided to NRC.
Since that time, and after intensive negotiations, the Swiss Government has granted authorization for NRC to discuss openly and publicly information on the Beznau incident, pro-viding the reports received from the Swiss are not made a matter of public record.
With regard to NRR activities, this event was mentioned, in the detail permitted at the time, in a public meeting with licensees of Westinghouse-designed reactors on May 30, 1979.
In addition, NRR plans to forward information on this incident to licensees and applicants shortly.
Should you require additional information or details, please let me know.
AW h Harold R. Denton, Director Office of Nuclear Reactor Regulation
Enclosures:
1.
Note dtd 8/21/79, A. Thadani to J. Heltemes 2.
Meeting summary dtd 5/02/79 3.
Ltr dtd 5/01/79, D. Ross to T. Anderson j Yk ynse M
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