ML19319B328
| ML19319B328 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 02/25/1976 |
| From: | Butler W Office of Nuclear Reactor Regulation |
| To: | Roe L TOLEDO EDISON CO. |
| References | |
| NUDOCS 8001150812 | |
| Download: ML19319B328 (6) | |
Text
o r -
o
.s.
Distribution:
NRC PDR W. Haass 0 3 I576 ktF TIC Docket No. 50-344[-
LWR #4 File R. C. DeYoung R. Heineman W. Mcdonald, Post Q-2 Mr. Lovell E. Roe R. Klecker Vice President, Facilities M. Williams Development ELD The Toledo Edison Company IE (3)
Edison Plaza, 300 Madison Avenue L. Engle Toledo, Ohio 43652 M. Rushbrook bec:
J. R. Buchanan, ORNL BWR BCs T.'B. Abernathy, DTIE
Dear Mr. Roe:
ACRS (16)
Based on our review of your analyses of the ICCS for Davis-Besso, IJnit 1, and of the B&W topical report entitled, "ECC5 Evaluation of B&W's 177-FA Raised Loop NSS", ve find that we require additional information to complete our review. The additional information we require from the Toledo Edison Company is identified in *.he enclosure.
Ve have already requested certain additional infernation from B&W pertaining to topical report BAW-10105. Uc are continuing our review of the contents of your letters dated July 9, July 21, September 5, and October 8, 1075, and of the topical report BAV-10105.
In order to maintain our licensin;; schedule, we vill need your response by April 5, 1976.
If you cannot nect this resnonse date, please inform us within seven days after receipt of this letter of the date you can neer so that we may revise our schedule accordingly.
Sincerely,
'Orif. d 23.?'i b'l W. R. Eder Walter 2. Butler, Chief Light Vater Reactors 3 ranch No. 4 Division of Project "1n. &ecant 9
D n
D Enclo9ure:
2ecuest for Additional Od Information D l Q
~' T P
O cc: See next page a
?
LWB LWR #4b.
o,,,c s,
g sv am * * =
- WRButler' _
- LEng,
_2/Eg/76 2/ 7.N/ 76
..rs,
Form AEC.318 4 Rev. 9 53 p ABCM 0240
- u. s. sovsamassar,mmtime orricas se,4.see.ese
. 8001150 8/.2 /
,.. ~.
~
e 2-Mr. Lowell E. Roe FEEE' G75 cc: Donald H. Hauser. Esquire The Cleveland Electric Illurinating Co.
P. O. Box 500'), Room 610 Cleveland, Ohio 44101 Gerald Charnoff, Esquire Shaw, Pitt: nan, Potts Trowbridge and 1:adden 910 - 17th Street, N. W.
Washington, D. C.
20006 Leslie Henry, Esquire Fuller, Seney, Henry & Hodge 300 Madison Avenue Toledo, Ohio 43604 1
I l
s OFFtCs P
~~~a SUNN A Ms &
-. + - - - * * - -
asss >
~~~
- ~ ~ ~ - - ~ - -
- - ~ ~ ~ ~ ~
Fene AEC 3ts (Rev. 9 53) AEG 0240 W u, s. eovenwassNT PemTme OPPsCes 1974-838-908
^
DAVIS-BESSE 1 REQUEST FOR ADDITIONAL INFORMATION 1.
Justify the selection of initial pin pressure and oxide layer for the CFT line break (referenced in BAW-10103 to FSAR).
Ex-plain not considering the Case 1 power shape previously shown to produce a higher PCT. What value of LHGR was assumed and why?
2.
With regard to the single failure analysis in your letter dated Saptember 5,1975; a).
The core flooc'.ng line isolation valves CFIA and CFlB will be required to have power disconnected and breakers locked open.
b)._ Attachment l' states that if valve HP1556 spuriously closed during the injection phase of a LOCA, there will
'e no effect on HPI capability. To confirm that your o
evaluation was complete, provide the details of your study which considered this spurious closure during a small break which allows RCS pressure to remain above the cut-off head of the HPI pumps for such a time as to compromise pump integrity (due to the loss of the 1 h-inch bypass lines). Provide the time that you assumed it would take before pump damage would occur and relate this situation to its affect on the capability to meet the criteria of 10 CFR 50.46.
D 3
Your July 9, 1975 letter indicated that, with the exception of decay
- h. eat suction' valves DH-ll and DH-12, no critical equipnent is affected by post-LOCA flooding.. Provide the level of water (above the con-tainment floor) assumed for the LOCA and include the calculations a
upon which this value is based. Also, the statement is made that a water-tight " trench" will enclose valves DH-ll and DH-12.
Pro-vide a description, with diagrams, of the trench and discuss the surveillance planned to ensure that this installation remains water-tight throughout the reactor lifetime.
4.
With regard to the partial loop analyses in your October 8,197.5 letter; a).
Provide an analysis of a break in the idle pump discharge.
b)*
Explain the double peak in cladding temperature under 20 seconds and explain why the 1st peak is more pronounced in this analysis relative to the 4-pump break spectrum and relative to the 3-pump analyses for other category plants.
-2 ~
3
~.'
,1 c).
Provide assurance that the PCT versus break size curve in BAW-10105 would not be significantly altered by partial loop operation.
d).
Submit the LOCA parameters of interest identified in the " Minimum Requirements for ECCS Break Spectrum Submittals," dated April 25, 1975.
e).
Explain the basis for the initial power level assumption of 77% for 3-pump operation.
~
f).
It is stated that the containment building pressure calculated by CONTEMPT is similar to the worst case in BAW-10105. Why didn't the lower initial core flow and power level for 3-pump operation result in a lower containment pressure?
g).
Provide the core-wide metal-water reaction for 3-pump operation.
h).
Submit the values of initial pin pressure and oxide layers assumed and justify the selection of these values.
5.
Provide your schedule for submitting the proposed Technical Specifi-cations affected by the LOCA analysis.
6.
Provide the passive failure analysis committed fer January (see your September 5, 1975 letter).
7.
With regard to the ability of, Davis-Besse 1 to cope with potentially high boron concentrations in the long term after a LOCA, the staff notes that Toledo Edison Company has referenced B&W topical report BAW-10105 (see letter dated July 21, 1975). The following add-itional information is required:
a.
11 ore recent boron dilution design proposals on such doc-kets as WPPSS and Oconee have the advantage of greater simplicity relative to the multi-mode piping networks described in the topical report.
Also, it is the staff's
. position that Mode 1 (forced circulation through the decay heat drop line) should not be attempted as a method to control boron concentrat.9n in the core during lond-term cooling. The succes's of this mode is not ensured because of the possibility of gas or steam entrainment in the decay
N o
+.-
heat' suction nozr.le.
Such gas or steam entrainment can result in severe damage to the decay heat removal pump.
Long-term heat removal requirements can exist for long durations (days or months) af ter the accident and^ continuous operation of one train of thc. decay heat removal system is required.
In the event of equipment malftnction in this train, no method is available to remove the decay heat if the other_ train has been previa.usly damaged.
For the same reason, step 7 on page-10-7 should also not be attempted.
It is preferred that a simple design exist for boron dilution whereby operator involvement with major ECCS components that fulfill the primary role of long-term heat ramoval is kept
'..mple and to a minimum. Accordingly, discuss alternate-A sr '
b,
,s
- indicators are not satisfactory instrumentation to ve.Ity that a minimum flow rate of 40 gpm is maintained.
The, staff requires flow rate indicators which will clearly show the operator that this minimum flow rate is achieved and maintained over the long term.
c, Discuss. common. power. supply problems and the procedure to restore a loss of' power ~ to essential valves.
Als'o, address possible access problems due to high doses should such a power loss occur after the shift to the recirculation mode.
{d.,Discussthecapabilitytotestthedilutionsystems.
Iej]Discussthefeasibilityofgravitydrainingfromthehotleg to the sump.
g,,
Indicate the feasibility of monitoring boron concentration levels during the long term.
a E
-, +
m.
)
=
8.
With' regard to the REFLOOD code resistance values in Tabic 4-2 of BAW-10105 used for loop venting calculations, insuf ficient.
information exists to support the values selected.
a.
Identify each paraceter which has been derived from actual measurements made on plant systems, compc :nts, models and/or prototypes. Provide calculations to show how these measured parameters were converted to the K-factors presented in Table 4-2.
b.
For each flow path shown in Table 4-2, justify the appropriateness of the flow resistance for Davis-Besse 1.
For example, it is'not clear that the most conservative areas were selected to serve as a generic calculation applicable to Davis-Besse 1.
c.
To allow a greater understanding of the effect of these resistances on reflood rate, re-submit Table 4-2 with the flow paths listed in decreasing order of importance to peak cladding temperature calculations. ' Provide the specific sensitivity study (peak cladding temperature versus K-factor) for the first, middle, and last value.
9.
It is noted that no additional flow resistance was added to the cold legs due to the HPI pumps injecting ECC water during reflood.
Evaluate the effect of an additional 0.25 psi cold leg AP upon the reflood rate and cladding temperature.
For the LOCA limit analysis, compare the existing time at which the reflood rate goes below 1 in/see to the new time calculated using the additional cold leg resistance.
10.
Justify that the assuced CFI line resistance is appropria'te for
~
Davis-Besse 1.
Provide the L/D's for the CFT line for Davis-Besse 1 and include the entrance and crit losses.
O S
e G
+