ML19309B057
| ML19309B057 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 03/29/1978 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| TAC-6710, NUDOCS 8004020661 | |
| Download: ML19309B057 (9) | |
Text
.
p 4E O'. 40lW REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS) f1STRIBUTION FOR INCOMING MATERIAL 50-312
.ID R W ORG: MATTIMOE J J DOCDATE: 03/29/78 SACRAMENTO MUN UTIL DIST DATE RCVD: 03/31/78
/PE: LETTER NOTARIZED: NO COPIES RECEIVED JECT:
LTR 1 ENCL 40 3PONSE TO NRC REQUEST OF 11/02/77... FURNISHING ADDL INFO RE THE PROPOSED JDIFICATIONS AT UNIT 1 TO PROVIDE OVERPRESSURE PROTECTION...W/ATT DIAGRAMS.
PLANT NAME: RANCHO SECO (SMUD)
REVIEWER INITI AL:
XJM DISTRIBUTOR INITI AL: ntf ooc ************** DISTRIBUTION OF THIS MATERIAL IS AS FOLLOWS ******************
GENERAL DISTRIBUTION FOR AFTER ISSUANCE OF OPERATING LICENSE.
(DISTRIBUTION CODE AOO1)
FOR ACTION:
BR PW'""
^~'""""/7 ENCL
,5 INTERNAL:
REG FILE **W/FNr' NRC PDR**W/ ENCL A a t**W/2 ENCL OELD**LTR ONLY HANAUER**W/ ENCL CHECK **W/ ENCL EISENHUT**W/ ENCL SHAO**H/ ENCL BAER**W/ ENCL BUTLER **W/ ENCL GRIMES **W/ ENCL J COLLINS **W/ ENCL J.
MCGOUGH**W/ ENCL EXTERNAL:
LPDR'S l
SACRAMENTO, CA**W/ ENCL REGION V**W/ ENCL TIC **W/ ENCL NSIC**W/ ENCL ACRS C,AT B**W/16 ENCL DISTRIBUTION:
LTR 41 ENCL 40 CONTROL NBR:
22COCeev '
SIZE: 4P+4P A'
- [Tw
.cooco******************************
THE END
- 004 0so GCf
p
,J ONU
~^
SACRAMENTO MUNictPAL UTILITY DISTRICT O 6201 S street. Bokh[hIa h,blifomia 95813; (916) 452-3211
'G B2 3l PM 5 17
. March 29,1978 cm r:
N J3Y;CES Director of Nuclear Reactor Regulation Attention: Mr. Robert W. Reid, Chief Operating Reactors, Branch 4 U. S. Nuclear Regulatory Comission Washington, D. C.
20555 Docket No. 50-312 Rancho Seco Nuclear Generating Station, Unit No. 1
Dear Mr. Reid:
Your letter of November 2,1977 requested additional information regarding the proposed modifications at Rancho Seco Unit No.1 to provide overpressure protection. On October 14, 1976, October 28,1976, and March 17, 1977 the District presented an analysis of, and proposed, the following plant and procedural modifications:
1.
The addition of a dual setpoint to the pressurizer power operated relief valve.
2.
Plant operating procedure changes to require the closure of a valve downstream of the high pressure injection pumps in each high pressure injection leg during cold shutdown.
3.
The addition of a low pressure trip to the high pressure injection and make-up pumps which would be enabled during cold shutdown.
The dual setpoint feature for the electromatic relief valve has been discussed with your staff in detail in recent telephone conversations.
[
Your letter of March 13, 1978 indicates that installation of this dual setpoint feature is acceptable and we are proceeding with the installation of this feature.
This work should be completed by April 17, 1978.
Other discussions with your staff regarding the low pressure trip of the high pressure injection and make-up pumps has led to the conclusion that this is not the most desirable modification to provide overpressure protection.
A reevaluation has been made based on this recent information.
l g,O a==ccce -
slkg m
O, f ^'
Mr. Robert W. Reid March 29, 1978 There are several plant and procedural modifications which could be made in addition to the dual setpoint relief valve.to provide the required redundancy for overpressure protection.
Some of the modifications are quite costly or could have a possible adverse impact on plant operation or the 1
safety function of the associated equipment.
The modifications which nave been considered are as follows:
1.
A second relief valve could be added to the pressurizer which would be enabled when overpressure protection is required. This modification would cost at least $400,000 and its installation would require considerable radiation exposure to the plant maintenance personnel.
This modifi-cation was rejected for these reasons.
2.
A low pressure (550 psi) setpoint could be added to the high pressure injection and make-up pumps which would be enabled when overpressure protection is required.
This modification would cost at least $5,000.
In addition, there is the possibility of a failure within such a system causing a failure within the high pressure injection system when required for emergency core cooling.
This modification j
was rejected for this reason.
3.
Technical Specification changes could be made requiring a valve downstream of each high pressure injection pump in each injection leg to be closed and/or requiring power to the high pressure injection pumps to be removed during cold shutdown.
If a malfunction were to occur to the make-up 1
system or decay heat removal system during cold shutdown, such a technical specification could make it impossible to abide by a technical specification requiring the ability to inject concentrated boric acid into the primary system during these periods.
For this reason, this modification i
was rejected.
4.
A modification could be made to provide control room annun-I ciation of the valve position for the motor operated valves downstream of each high pressure injection pump in each injection leg, and annunciate if power is available to the high pressure injection pumps during cold shutdown.
In addition, annunciation can be provided which will alarm to indicate a failure of the make-up valve in the full open ps,Mion. These modifications can be accompanied by plant operavng procedure changes which will require closing a valve downstream of each high pressure injection pump and the removal of power to each high pressure injection pump.
This modification was chosen because its failure could not affect the high pressure injection system when required for emergency core cooling or boron injection.
/
D.
fT a
4 Mr. Robert W. Reid March 29,1978 We have not proposed technical specifications allowing the power operated relief valve to be removed from service only if the high pressure injection valves are closed and power is removed to the high pressure injection pumps.
We consider it more desirable to make this a requirement of the plant operating procedures since annunciation is being provided if (a) the low setpoint feature is required, (b) the block valve is closed removing the power operated relief valve from service, (c) power is available to the high pressure injection pumps, and (d) an injection valve is open.
The attached drawings should provide the details necessary for a thorough review by your staff of the proposed modifications.
Since the District considers these additional modifications to be an unreviewed safety question, we do require your approval before they will be implemented at Rancho Seco Unit No.1.
We request your review be completed in time to allow us to implement these modifications during the next refueling outage.
In summary, the following features are being made, or proposed, to provide overpressure protection:
1.
A dual setpoint on the power operated relief valve to open at 550 pounds and close at 500 pounds, to be installed by April 17,1978.
2.
Annunciation to alarm when plant pressure is reduced below 550 pounds and that overpressure protection should be enabled.
This alarm will cancel when the dual setpoint feature is enabled. This feature will also be installed by April 17, 1978.
3.
Annunciation to alarm when the block valve is closed, removing the power operated relief valve from service, to be installed at the next refueling outage.
4.
Plant operating procedures will require closing and removing power to (or closing and tagging if manual valves are chosen) a valve downstream of the high pressure injection pumps in each of four injection legs.
5.
Annunciation of the four motor operated injection valve
-positions, to be installed at the next refueling outage.
i l
6.
Operating procedure changes requiring power to be removed from two high pressure injection pumps.
7.
Annunciation of the status of power to these pumps, to be installed at the next refueling outage.
l
a O
.Mr. Robert W. Reid ~ March 29,1978 8.
Annunciation to alarm high ' flows which.would be caused by i
the failure of a make-up control valve in the full open position, to be installed at the next refueling outage.
14! believe these modifications satisfy the requirements of your November 2,1977 letter.
If we can provide any additional-information, please contact us.
Sincerely yours,
?. hrYA J.' J. Mattimoe Assistant General Manager and Chief Engineer Attachmen ts t9
,_7 y
c w...
.+m,
D.SMUD n
)
SACRAMENTO MUNICIPAL UTILITY DIST".lCT p,
1
<p DATE gugJgCT OVEicP2 ESC,UCC E'bO'/727?DU h LA ?M J5-2'7-Tb Lonic
' Dong.emr).
DEFT. }ed. EUG.
[
L.W. Sroneasov.
- * **"** NRC LETMe DATED /l T[
n,.s: " ~'*7" Sn.3/2 OVER.PAi?K55UC E ksiu SOA/
SP I r*.A 7t='.O Rt.nen - Pwe.
%e A va.
'M f*fi MM
P23R R Ovancesssues 'Rearscr:rco
~
Sri nc.rpo A1.AeH-Hiqa R.ad g
"M
- 2. 0. Sv'<TnM
. ~ " -
~~~
'~
R.C. Intar-g
....i.a.
.2 OVEAPC'W2 a2JC MECT/CA)
SrrE m v
-.. '... "... T
~
- ~ ~
~~'
SFY25609 h.AA?m - R.C. Zw.er-s,.
- ~
Mn o OPEA)
^ i
~
SFV 2.5810 L.
Va t.ve A~1.s Dom >
. ' ' ~
~
~~
Mai Op=3.1
~'
^
.. '. ' SFV238/)
D
~~":.-.................
..~
~
M1-Ocn) U
~~
... ::'.~
SFV 23812
- ~
g, g,.,,
Ovax.fr.Essven PEr.oi ns aCU y,_
_p M V Z1505 M~
Cmn
~
....g..,...
__. 3.u _..
-r------,-------'-~-
- E "Q E C a::cor*
"ANo' Cseau er l
1 l
THIS DOCUMENT CONTAINS POOR QUALITY PAGES s. *
.6-
{ *
- MM MO
, t-a f
9.
w, _
e 3,
1
=..
i a___
a
.u i
ae
-,a
.,,,,m e i
ga i
l, is j _
ii
.I d
4 tt l-rg o, o.
o
.mQ
~,
...4.y_....._.
_4..._.
g. 4_
Dh e
m,Re 23 g
ho
. i _...
.. '... _...._[ : '.. -
I e
g'..
\\
I g
}
g Q
, 4" Ij X
l E
M 6
o R
o" 4
0 k
~.
~
g ll V
ll
..V a
a3 e,s!,
2 J!
J,i t
no
~
n
=
il-llo iitsd F.
,g g
m.
44 t
I l
3 n
- tlI
$)
E2,!
~
s b1
~
8 9
~~
'\\r l'
V yd ii es jg m
a RR HI u
g y
e a
E o
a e
i ll ll V
ll l
ObrA 03T
.LHD3 ameo asanunop u E -0.c 4wxxu M,-3 -// N6'CI 7" " 3 I JB' N
,3,,,,,,,
' NN Hd u 13 'F1,,
- tW g *nu,*),LeBo i
- bitmbyrq Aysu.ngomrsy 9/ -LZ-C (YOf L. =r /Q 3nSS23d23AQ 7
31VO 13Bf9ftS 8*
d 131H1S10 All' Illa "lVdI31NOW 01N3MVH3VS anne e -
c-o
H4Prol H3CEE i
k
,H4 PIol tsc-3
. y_ s -
,_7_,_7,o,, n rass.
g
_w p,,
~
- d. 22zeCs i_se 6 ~
=a12,z.e.c. *= h =a
^
-e K W 4
4, e
,-a so o
- S<
b, pg asi',
i g,
I'
}
f
[
- f$
. D4 E
E
/-l}(
T~-Pcf
=
Ji4+proh
<W 4,, M I 5-10 s-1-5s p.
O d
cz efI
, HscKa,e, g[w
,, H3cv,Ja ni ros.z a- -
~~PR 0
sT
$k
- t
/d 4
'Pov2.15J) i
.~
P R.
y Q
z o g
g 5
':)
~>S (.- 3 1
5 9'
~.N
~N C
E. M 1
(0 yk 2
gb4 H4PIol
-$ CourAcTs l~ mom 40%, ret.AV 3
{
3J 2 2 -14 Loca rtou 3-10-9 (H4Prol)
~.
gR NI5 07-6t f
b4-q
/
> Q, u
2 t
Ey k
8E'_17/Rc BM
% Ag
~
~
)S sn 5
@L a
A I O*k f0 fl a
H AP.t6 t 5
4-s-1-15 gg
- gge, y
'b.
" H)g"R
- . ' P O.,.',': Y h ~; -
,v,' 9 ; ys;y.;p -
. h. - ;_
a g
PRESSUR/ZER REL/EF VALVE
~
...,,, 1...,-,.,,..,.,,, PS V-2/S// e~ zo.5 so, a.
- : i : : ! ;. :,J.:J:.: : i,. - -- - : t
.a
-t 6
j g ug OtM H3fint j
s g
-4
- s
.-s.,
,,.j....
.,l.,.,,-,-
1-. 8
. *=
2 i..-
[
10 pi
.,.e.
l se
,y.,,-
a Q
y e4 a
t-
\\n
_s.
g g **;
e p,
p c4 j
~ s.,L;J i
g
--.~, -
4 I
4 o
q, si
.Tj g.4.
9 4.fss -;
. s-; h es-n b.ra.
'Ji..Q'1
].
..I (f1 1
.f., 2, v,...
s Eg o
?
'b,,) W
_.i V
J 4
i
__g9
~]
I T
b.
y.l-p,.; :
1..
6 g
- ! y. ;.. '
i
- i..
q c)
V3 p
y O
t
-. -.- l g
g i
q p
r
(-
]
~;[~~
{-[
. ", N es' i.*
-I
' [.."
. I, 2
.i x
wg i. '.
..I
--g n
c:
e e.
,.y c
-- -l i !
{s 1
i -
. +
i g
q :...-.;..
i gl.. ---
)
i i e
6 a t :
-e L. **
I a.
c.
e L
a f
fE)E o " j ' '
n.
i z
i v.
Tt t
-e i
'c.
g a vi 0.
~
i
~
l
~
h 98 '
._ -- e
)
1 Z /S - C t.;irw q l
(( ~ U */[ NWC DM DN
~~
33N3W3d3W A8
- w rab.u3a doo7 inawmr.1swz 9/o -/,o 3 -T f19 2'dMc'Id 39AQ alvo Asaretts Y
- d 131HIS10 Ailll10 "lVd!3INOW 01N3WVM3VS i
I
\\
-