ML19224B863
| ML19224B863 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/12/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19224B853 | List: |
| References | |
| 790510-12, NUDOCS 7906270104 | |
| Download: ML19224B863 (4) | |
Text
ENCLOSURE
SUMMARY
OF 229TH ACRS MEETING MAY 10-12,1979 The 229th ACRS meeting was held on May 10-12, 1979.
The meeting was principally a continuation of the Comittee's consideration of the implications of the accident at Three Mile Island, Unit 2 (TMI-2).
(A special ACRS meeting on the implications of the accident at TMI-2 was held on April 16-17, 1979).
The agenda included a report by the TMI-2 Accident Implications ACRS Subcommittee and presentations by the suff, Combustion Engineering, Westinghouse and TVA (on the implications of TMI-2 on it:, Sequoyah Nuclear Plant). The staff also briefed the Committee on the Oyster Creek incident.
TMI-2 Accident Imolications ACRS Subcomittee Report As a result of its three days of meetings (April 30, May 1 and 9,1979), the TMI-2 Accident Implications ACRS Subcomittee developed a number of recomendations to present to the Comittee for its consideration.
Among those presented by Dr. Okrent, the subcommittee's chaiman, were the following:
1.
Prepare a letter addressing those matters previously presented to the Commission as well as any others.
2.
Assign to appropriate subcommittees those matters reccmended by the Subcommittee for further consideration.
3.
Consider how to proceed with pending license aaplications.
4.
Consider how to proceed with the Babcock & Wilcox plants with operating licenses.
5.
Consider the adequacy of various philosophical approaches to safety such as the single-failure criterion.
2JD dic 6.
Consider the adequacy of plant operating procedures.
7.
Consider the proposed reactor safety research program including the need for
" exploratory" research.
7906270lOf'
. 8.
Consider the need for reactor vessel level indication for pressurized water reactors.
9.
Consider the need for operating experience information to be fed back to utilities' technical and operations staffs.
- 10. Consider the need for further operator training.
- 11. Consider the effects of plant-specific features such as UHI on natural circulation.
12.
Consider mechanisms for completing generic matters such as purge valve closure against a LOCA.
- 13. Consider quantifying risks te provide safety goals and thresholds for actions such as a limit for determining whether a plant should be shut down as well as to put the risks associated with nuclear power plants into perspective with other risks.
Staff Presentations Brian Grimes reported on the current status of TMI-2. The reactor is steaming on the "A" steam generator using natural circulation.
Primary coolant pressure is approximately 775 pounds per square inch and decreasing. The highest incore thermocouple U
reading is approximately 310 F and decreasing.
Activity levels inside the containment are approximately 130 Roentgens per hour (80 Roentgens per hour from gases, principally xenon and krypton, and 50 Roentgens per hour from plateout).
Offsi te activity is near background. Current plans are to continue to steam on the "A" steam generator until the pressure decreases to 500 pounds per square inch, continue steaming or go water solid until the pressure decreases to 300 pounds per square inch and then decide how to proceed to atmospheric pressure.
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?7~b qG Ls Denny Ross and Jack Heltemes discussed in ganeral the staff's review of the licensees' responses to the various I&E bulletins and the implementation of the Committee's recommendations of April 7,17 and 20,1979.
They also reported that confirmatory orders had already been issued for Oconee and Rancho Seco and those for the other Babcock & Wilcox plants were imminent. Tom Cox, Nat Villaiva, Pat O'Reilly and Bill Kane presented more detailed information concerning the licensee's responses to the I&E bulletins for the Babcock & Wilcox, Combustion Engineering, Westinghouse and General Electric plants, respectively.
Zoltan Rosztoczy discussed the status of the staff's review of Babcock & Wilcox's small break analyses.
Zoltan reported that Babcock & Wilcox has considered a number of additional small breaks as well as the effects of loss of auxiliary feedwater to one steam generator. He also outlined a proposed staff position which would, if approved by management, serve as a basis for lifting the confirmatory orders for the Babcock & Wilcox plants. The Committee's questions concerned principally the need for reactor vessel level indication, the means by which reactor vessel level could be inferred and the need for experimental verification of the analytical results.
T' a Committee asked the staff to consider the adequacy of the vendors' modeling of natural circulation.
Ed Jordan, Paul Check, Frank Coffman and St.n Nowicki briefed the Committee on the Oyster Creek incident.
Ed reported that the licensee's conservative calculations showed that the minimum collapsed water level over the core was frcm one to one-and-one-hal f feet. The Committee's questions concerned principally the timing in which the operator reacted and wnether or not the operator acted in accordance with the established procedures.
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r Combustion Engineering, Westinghouse and General Electric Presentations Reoresentatives of Combustion Engineering, Westir.:'Luse and General Electric described tre principal design features of their plants and discussed the applicable I&E bulletins and Committee's recommendations of April 7,17 and 20,1979.
For the pressurized
4 water reactors, tha Comittee's questions concerned principally the need for reactor vessel level indication, the means by which the level could be inferred and natural circulation.
For the boiling water reacters, the Cemittee's questions concerned principally the effects of adverse operator action and the need for incore the rmocouples.
TVA Presentation Representatives of TVA discussed the applicable I&E bulletins and Comittee's recomendations of April 7,17 and 20,1979 as they pertain to the Sequoyah Nuclear Plant.
Harley Silver represented the staff. The Committee deferred action on Sequoyah until its June meeting as TVA representatives advised that the plant will not be ready for fuel loading until the first of July.
Miscellaneous Matters The Comittee announced that Dr. Harold Lewis was acting as a consultant at the meeting and that he would have full member status at the June meeting.
The Comittee deferred action on Comissioner Gilinsky's request concerning the relative merits of :irconium and stainless steel cladding until its June meeting.
Comittee Actions The Ccmmittee wrote two interim letters concerning TMI-2. The first letter addressed principally those matters presented.' rally to the Commissicn on April 17, 1979.
The second letter addresses principally other matters recommended by the TMI-2 Accident Implications ACRS Subcommittee.
,l3'3 Li3 The Committee wrote a brief letter concerning the quantification of risks,