ML19319B776
| ML19319B776 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 12/15/1972 |
| From: | Anthony Giambusso US ATOMIC ENERGY COMMISSION (AEC) |
| To: | Sampson G TOLEDO EDISON CO. |
| Shared Package | |
| ML19319B777 | List: |
| References | |
| NUDOCS 8001270246 | |
| Download: ML19319B776 (4) | |
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t DEC 15M2 Docket !;o. 50-346 99I D
D W6 ite Toledo Edison Ccaiparty g n }b q
ATHl: Mr. Olenn J. Sempson D
y[J Vice Prea W nt, Fuwer 3
3C0 h21 son Plaza
'Ibledo, Chio 43652 Gentlecen:
'Ibe iterulatory staff's continuing review of reactor pcnder plant safety indicates that the carmec.uences of postulated pipe failures outside of the contairrent structure, including the rupture of a main stem: or feedwater lira, need to be adequately docuuented arx1 analyzed by 11ccraees arx1 applicants, and evaluated by the staff as scen as possible.
Criterian !b. 4 of tM CMasicn's General Design Criteria, listed in A;perdix A of 10 GTR 50 requires that:
"Etructurcs, systecs, and cmocnents 1:cportant to safety shall be designec to acccxrodate the effects of and to be empatible with the env1.w.tal conditiam associated with nortel operaticn, maintenance, testing arxi postulated accidents, $mlivMng Icss-of-coolant accidents. Sese structures, systems, and cor.penents shall be c4supclately protected against dynamic effects, including the effects of missiles, pipe whippirg, and dischargirt fluids, that may result fra:s equip:sent failures ard frcut events and concitions outside the nuclear power unit."
2e previous version of the C imatm's General Cesici Criteria also reflects the above requirecents.
Thus, a nuclear plant should be designed so that the m actor can be snut-
.icwn and maintained in a safe shutoown condition in the event of a postulated rupture, outside containment, cf a pipe containing a high energy fluid, including the double ended a gture of the largest pipe in the main steam and feedwater systecs. Plant atmotures, systers, and components important to safety should be designed and located in the facility to acerwerv' ate the effects of such a postulated pipe failure to the extent neecammy to assure that a safe s!natdoom condition of the reactor can be ac-Mahal and maintained.
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'Ibe 'Ibledo Edison Capany :
Eased on the infomation we presently have ayn11nhle on the Davis-Besse plant, we understand that steam lines pass through the upper level of the amr111ary building in the space above the control recxa. Failure of either overpressure of the closed ccupartment or pipe whip appears possible. FItsa this it appears that scrae modification of the facility may be necessarJ.
3 We request that you provide us with analyses and other mlevant inforration needed to detemine the cweequences of such an event, usirg tre guidance provided in tre enclosed general infomation request. 'Ibe enclosure represents our basic information requirements for plants mw being cen-structed or operating. You should deter h the applicabi E ), for the Davis-Besse fact'ity, of the ites listed in tre enclosure.
If the results of yoar analyses indicate that changes in the design of stmetures, systeca, or ccmporents am racessar/ to assure safe reactcr shutdown in the event this postulated accident cituation should cccur, please provide infomation on your plars to revise tre design of your facility to acccamodate the postulated failures described above. Any design modifications proposed shculd include appropriate consideration of the midelines and requests fcr inferraticn in the enclosure.
We w211 also need, as soon as pcssible, esti: rates of tre scredule for design, fabricaticn, and installation of any modifications found to be necessary. Please infom us within 7 days after receipt of this letter when we may expect to receive an E==ulent with your analysis of this postulated accident situatien for the Davis-Besse facility, a descripticn of any proposed modifications, ard the schedule esti=ates described above.
Oi.xty copies of tre amencment shculd be pzuvided.
A copy of the Cmenhsion's press announcement on this matter is also enclosed for your infomaticn.
Sincerely, Criginal Signed by A.Glambussa A. Gim=+ e e, Deputy Dim eter for Peactor Pzujects Dimetorate of Licensing
Enclosures:
As stated cc: See next page
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' 'Ibe Toledo Edison Ccs:pany '
t cc: Mr. Donald H. Hauser, Esq.
'Ibe Cleveland Electric m = Matirg Co.
P, O. Box 5000, Pocan 610 Cleveland, Ohio 44101 Isslie Eenry, Esq.
Fuller, Seney, Henr/ & Fodge 800 Owens-Illinois B1Jg.
405 Madism Avenue Toledo, Otto 43604 Mr. Gerald Ommoff, Esq.
Shaw, Pittman, Potts, Trewbridge & Padden 910 - 17th St met,ii. W.
Washington, D. C.
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i No. -
P-429 FOR IMMEDI ATE RELEASE
Contact:
Frank Ingram (Wednesday, December 13, 1972)
Tel.
301/973-7771 AEC REGULATORY STAFF REQUESTS DATA ON PIPE BREAKS IN NUCLEAR PLANTS The Atomic Energy Commission's Regulatory Staff is asking all utilities that operate nucicar power plants or have applied for operating licenses to assess the effects on essential auxiliary systems of a major break of the largost main steam or feedwater line.
These lines carry steam from inside the reactor containment building to the main -turbine in the turbine building, and hot feedwater back.from the turbine condenser.
The utility assessments will be evaluated by the AEC's Regulatory Staff.
The probability of a steam-line rupture is low.
Nonetheless it will have to be considered in the AEC's safety evaluation.
The review of the pipe break problem has been under way for several weeks.
It was started af ter the Advisory Com-mittee on Reactor Safeguard received a letter raising questions about the location of pipes in the two-unit Prairie Island plant in Minnesota.
The Regulatory Staff has reviewed the Northern States-Power Company application to operate Prairie Island, and on the basis of data available it has concluded that design changes.will be required at Prairie Island.
Based on the new information--to be submitted by utili -
ties as soon as possibic--the Staff will determine what' corrective action, if any, is necessary in each case.
The changes could include such steps as relocating piping, pro-viding venting of compartments, the addition of piping restraints, and, in some cases, structural strengthening.,
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