ML19319B334
| ML19319B334 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 11/14/1975 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Roe L TOLEDO EDISON CO. |
| References | |
| NUDOCS 8001150827 | |
| Download: ML19319B334 (4) | |
Text
-.2 m mwg NRC PDR becs: J.R. Buchanan, ORNL L PDR T.B.Abernathy,DTIE Docket No.: 50-346 Docket File ~
LhR 2-3 Rdg VMbore T4 1 4'975 RHeineman 101cDonald Toledo Edison Conpany thR TC's ATIN: Mr. Lowell E. Roe ELD Vice President IE (3)
Facilities DeveloInent LEngle Edison Pla::a EGoulbourne 300 Madison Avenue IR BC's Toledo, Ohio 43652 LhR BC's ACRS (16)
Gentlenen:
TIC PF The.NRC staff recently ccepleted a site visit to Davis-Besse, L'ait 1 (DB-1) on October 15 and 16,1975.
Based on observations of the ECCS strp during that visit, we request that you provide additional infomation as stated in the enclosure to this letter. h'e will require some neans of testing to confim the suction line pressure drop :alculations. Most, but not all of the requested infomation concerns the area of adequate NPSii.
h'e will need your responses to the enclosure by recer.ber 5,1975. If you cannot met this resnonse dite, please infom us within seven (7) days after receipt of this lett:r so that we :nay revise our scheduling.
Please contact us if you have a:rf questions regarding the enclosure provided.
Sincerely,
<:.:n!;6,ig A. Schwencer, Chief Light h'ater Reactors Branch 2-3 Division of Reactor Licensi:t;
Enclosure:
Request for Additional D**D Infomation ow ccs: See next page
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ADDITIONAL INFORMATION REQUIRED ON ECCS SUMP TESTING FOR DAVIS-BESSE 1 W
1.
The FSAR provides the following information (Page 6-79);
NPSH REQUIRED NPSH AVAILABLE DH Pump G 3000 gpm 8.5 ft.
9.26 ft.
BS Pump @ 1300 gpm 9.0 ft.
11.37 ft.
Provide alf calculations of total elevation head available and total head required, including velocity heads, head losses, elevation heads, etc. Also, submit the values utilized in the NPSHa equation on page 6-79.
Specify the flood level assumed inside the containment and provide the basis for this assumption in terms of equipment volumes displaced and the type of LOCA assumed.
Confirm that the location of the assumed break resulted in the minimum flood level inside contain=ent (i.e., most water left in.the primary system).
2.
Discuss the piping runs from the sump in terms of potential air bindage as the flood level rises after a LOCA.
3.
Discuss tests by the manufacturer to confirm the required NPSH for each pump at Davis-Besse 1 (Decay Heat and Building Spray).
4.
It is noted that less than.1 ft. margin exists between NPSH required and~available for the DH pumps, and less than 3 ft.
for the BS pumps., Discus; :he potential that such margins could cignificantly diminisn after a LOCA due to pump flows in ex [eds of design.
- 5. What is the minista test flow rate at which Toledo Edison C wouldclearlybeabletoconfirmpreviousheadlosscalcula5[o"ds (see question 1)? Discuss the basis for this conclusion.
. ~g 2-6.
Discuss the feasibility of expanding the capacity of the sump to allow design flow rate testing. As an alternative, discuss the possibility of installing temporary piping to permit a pressure drop test at design flow rates (or the flow proposed in response to question 5).
7.
What is the maximum gravity drain rate capability to the sump from the BWST?
8.
With regard to the potential for vortexing, submit your bases (including analyses and supporting test data) for concluding that this phemomenon would not occur.
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