ML20008F424
| ML20008F424 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 03/05/1981 |
| From: | Lundvall A BALTIMORE GAS & ELECTRIC CO. |
| To: | Clark R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8103130432 | |
| Download: ML20008F424 (3) | |
Text
.
BALTIMORE GAS AND ELECTRIC COMPANY P. O. B OX 1475 B A LTIM O R E. M ARYLAN D 21203 March D, s ARTMUR C. LUNCVALL.,jR,
[
%*l j
Q'-
/
V Vict Pat siot*st u
t.
8 am s_
gg l s l%I"m Office of Nuclear Reactor Regulation
'n U. S. Nuclear Pegulatory Commission pron 8,
~
Washington, D. C.
20555 9, " cowiso" C,
/
Attn:
Mr. Pobert A. Clark, Chief qf Operating Peactors Branch #3
' a; c'
Division of Licensing
Subject:
Calvert Cliffs Nuclear Power Plant Units Nos. 1 & 2, Dockets Nos. 50-?l7 & 50-318 NRC Recuirements for Auxiliary Feedvater System Beferences:
(a) Ltr. from Eisenhut to Lundvall dated 11/7/79, same subject.
(b) Ltr from Lundvall to Clark dated 11/18/80, came subject.
(c) Ltr from Ash to Conner dated 2/2/81, AFT System Modifications Gentle'.en:
Feec mendation GL-2 of reference (a) required that licensees with plants in vnich the primary AW system vater supply passes through valves in a single flow path, but the alternate 124 system vater supplies f
connect to the AW system pump suction piping downstream of the above i
valve (s) should install redundant valves parallel to the above valve (s) or provide automatic opening of the valve (s) from the alternate water supply upon lov pump suction pressure. Reference (c) informed the NRC an to how we were going to modify the AW suction piping to comply with this recommendation.
'41th the entire plant unde. going an analysis by the Interin Feliability Evaluation Program task force, we decided to determine the impact on system unavailability of various proposed modifications to the suction piping line t o of the /E4 system. The analysis resulted in the following:
Tl T2 Present System 5 9 x 10-3 1.2 x 10-2 Modification A 7.h x 10-5 7.7 x 10-5 Modification B 6.7 x 10-5 7.1 x 10-5 81031~80 M
/
Mr. F. A. Cl ark Pace 2
" arch 5, 10'1 The above numbers represent the unavailability of the AFW system during two different transients. Tl involves a demand for the AFW systen in which there are no soecial circumstances. T2 transients are demands for AFW system when there has been a steam generator (S/G) rupture, i.e.
loss of one R/G. Modification A includes those design chances discussed in references (b) and (c) with the excention of installine the typasses around 1-AF7-161 and 2-AFW-161 (see attached dravinc for valve location).
Modification B presents the decrease in unavailability obtained by installing the bypasses around the above nentioned valves.
As can be seen from the above nunbers, installine the bynasses around 1-AFW-161 and 2-AFW-161 does not significantly i=preve the avail-ability of the systen.
It vill not even improve reliability by a factor of two.
We estinate the cost of installing these two valves to be Ah0,000.
This dnes not include replacement power costs due to the outare being longer because men are diverted to perfor= this task.
In addition to this, it may be necessary, because of tech spee requirements, to shut down both units at the same time for this work. To avoid shuttinr devn the unaffected unit we vould have to maintain 150,000 gal 2cns in the alternate condensate storage tank (CST). The alternate CST (No.11 or No. 21) is the normal source of makeup water for the unit's condensate systen and detending on makeun requirements ve may not be able to =aintain the required 150,000 gallon capacity. Without denonstrating the operability of the alternate CST've vould have to shutdown the unit within 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> per tech stec 3.7.1.3.
It currently costs $760,000/ day / unit for replacement power.
Even based solely on the Sh',000 expenditure to install these valves, we feel that the small increase in availability does not varrant j
the cost. We propose to nodify the suction piping lineut as discussed in reference (e) to that shown on the attached drsvine.
We request the NRC review this procesed nodification in licht'of the infornation provided on costs and reliability.
Due to the lonc lead time associated with ordering equipment we desire a respense as soon as posrible. Should you have any questions, feel free te contact us.
4 Very truly yours, _
f
/
,,/ /*
j cc:
J. A. Biddison, Esquire G. F. Trowbridge, Esquire
- Messrs. E. L. Conner, Jr. - NRC J. C. Ventura - Bechtel P. W. Kruse - CE 1
O
\\
4f Y 5 v i(N
-s
?c
'k N
lt b
pg n go
? '4
%u s
3 s
e, N'i' 1 '
N4 4 W4 s
D.
4 M
h s
h A
s2 m
4'N N
4 5
N "A
X 3
7 4
4 s
N*
%v l'L o
i a N
4kN
>a
=
-Q
\\x k,,
Q N
2 L a 3 c
M n
y k
b
(
N Q
Q k
3
%v
- N a
4 S
%e N
h
?
N y
s e.
A P00RORSNAl.