ML19249B187
| ML19249B187 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 08/01/1979 |
| From: | Fraley R Advisory Committee on Reactor Safeguards |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML19249B183 | List: |
| References | |
| 790725, NUDOCS 7909040062 | |
| Download: ML19249B187 (3) | |
Text
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NUCLEAR REGULATORY COMMISSION UNITE D ST ATES f ' 'i ADVISORY COMMITTEE ON REACTOR SAFEGUARDS f M..
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j July 25, 1979 i
Harold R. Denton Director, Office of Nuclear Regulatory Regulations AGS REVIEW OF THE FLCATIM NUCLEAR PLANT CORE IADLE DESIG4
SUBJECT:
At the June 27, 1979 ACRS Subcommittee Meeting on the Floating Nuclear Plant, members of your staff requested that the ACRS meet at an early date to discuss the proposed FNP Core Ladle Design and to write a letter to Mr. Gossick commenting on that preliminary design prior to the NRC Staff's The Acting ACRS Subcommittee Chairman issuance of its safety evaluation.
informed your staff and representatives of Offshore Power Systems that the suggestion to hold an early AGS meeting would be considered at the July 1979 AGS meeting.
The proposal to hold an early AGS review of the conceptual design of the FN? core ladie was discussed at the July 1979 ACRS meeting.
It was decided that additional i.nformation, as indicated below, is necessary be-fore the Cocmittee can proceed with its review of the FNP.
Items Related to the Imcact that the Core Ladle Will Have on Other a.
Containment Structures Calculate the fraction of decay heat radiated frcm the pool 1.
for the proposed design.
Calculate the effects of heat radiation in Item 1 on the rate of:
2.
(a) disintegration and collapse of exposed concrete disintegration and collapse er melting of concrete behind (b) the 6 inch magnesite brick wall (c) collapse of steel from the reactor cavity.
3.
Discuss the consequences of Itan 2 with respect to:
(a) loss of integrity of superstructures (b) loss of hearth capacity 7909040 6 6 [
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AC55 Review of FNP Core Ladle Design July 25, 1979 (c) impact resistance of the hearth and its supports (d) integrity of structural steel members.
Discuss the stability of the 6 inch magnesite brick wall above the 4.
hearth level with respect to:
(a) loss of brick by spalling (b) differential motion with respect to the hearth, concrete walls, and anchors loss of concrete behind the wall by spalling, disintegration, (c) and melting at calculated temperatures, or at temperatures indicated in Fig IV-6 of OPS Topical Report No. 36A59 (d) slagging reaction between the brick walls and melted concrete.
Discuss the fluxing of magnesite brick by siliceous material falling 5.
into the hearth.
6.
Discuss the properties and merits of basalt as a concrete aggregate.
7.
Discuss the possibility of the heat flux being higher on the sides of the molten mass than on the bottom (FPG conclusion for concrete melt) with melting going hori::entally faster than vertically.
b.
Items Related to Three Mile Island Accident 1.
Discuss the possibility of the Upper Head Injection System re-leasing nitrcgen into the primary system and impeding the ability to establish or maintain natural circulation.
2.
Discuss the acceptability of the single failure criterion.
3.
Discuss the timed sequence of events upon the loss of all AC power before core damage will result.
4.
Discuss the reliability of the auxiliary feedwater system.
5.
Discuss how H buildup in the ice condenser containment is dealt 2
with follcwing a 'IMI event and following a core melt.
6.
Discuss how the FNP comcensates for the difficulty, due to the re-note location and the lack of space available, in improvising new systems and techniques'in case of an accident.
7.
Discuss how one faces lack of flexibility for design changes due to the compactness and lack of available space en the FNP.
OCC.CSO
July 25,1979 ACRS Review of Core Ladle Design Items Concerning the Effects of Changing Base Mat Materials c.
Discuss the effects of changing the base mat from concrete to 1.
ragnesium oxide.on the probability of a major air release during a core melt accident. Discuss the comparisons of probabilities and dose levels for air releases associated with concrete and ragnesium oxide during a core melt accident.
Discuss the consideration given to the use of a vented containment.
2.
Discuss the consideration given to the use of sea water for venting and/or cooling a molten core.
Discuss the change in position for allowing the FNP to be placed 3.
on riverine and' estuarine sites. Has the proposed installation of the core ladle changed the NRC Staff's position on this matter, if What actions and in what time period, are considered so, why?
practical to isolate the core for a riverine or estuarine site?
Discuss the NRC Staff's position that the ENP Core Ladle is con-4.
sidered an environmental issue and not a safety issue.
Additional Information Recuested From the NRC Staff d.
Provide available information on the Sandia 100 plant liquid path-1.
way study.
Provide available information on the WASH-1400 type study of the 2.
ice condenser type plant, along with a comparison for non-ice condenser type plants.
Ecllowing receipt of Offshore Power System's respanse to the items listed above and a written evaluation by the NRC Staf f, another ACRS Subcommittee Please advise us of the date by which you believe meeting will be held.
the above information will be available so we can schedule related ACRS activities.
R. F. Fraley Executive Director cc:
D.
Muller, DSE E. Case, NRC D. Vassallo, DPM F. Schroeder, DSS
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