ML20206Q219
| ML20206Q219 | |
| Person / Time | |
|---|---|
| Site: | Callaway  |
| Issue date: | 04/15/1987 |
| From: | Schnell D UNION ELECTRIC CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| ULNRC-1492, NUDOCS 8704210365 | |
| Download: ML20206Q219 (5) | |
Text
"Umov
.Etscraic s
1901 Gratiot Street. St Louis Donald F. Schnell Vce President April 15, 1987 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Washington, D.C.
20555 Gentlemen:
ULNRC-14 9 2 DOCKET NUMBER 50-483 CALLAWAY PLANT RCSPONSE_TO N_RC_ QUESTI_ONS_ _0_N _AMSAC EQUIP _M_ENT l
Re fe rencos 1.
ULNRC-1472 dated 3-19-87, Response to NRC Safety Evaluation of WCAP-10858-P-A l
2.
OG-87-10 dated 2-26-87, Addendum 1 to l
This letter provides responses to questions discussed during a conference call between NRC Staff, their consultant EG&G, WCNOC and UE personnel on March 31, 1987 concerning the common AMSAC design described in Reforonce 1.
The questions addressed heroin are paraphrased from that discussion.
1)
Will the AMSAC syntom have a variable timer in accordanco with Addendum 1 to WCAP-10850?
Ronpons3 The additional requirements for variable timo delaya discuased in Reference 2 are not applicable to the steam generator lovel logic option chosen by UE and WCNOC.
The variable timo delays are applicable to the low foodwater flow l
logic and the foodwater pump and valvo statua logic.
As stated in Reference 1, the AMSAC signal will be delayed approximately 25 seconda to permit the Reactor Protection System g
coa:
(RPS) to provide the first trip signal.
This statement wan based T@
tipon information contained in WCAP-10858.
Section 11.0 on page h
3-6 of WCAP-10858 requiron AMSAC to trip the turbino within 30 acconds.
Thio 30 accond responao timo in defined no the timo go interval following a stop input in steam gonorator water level l
g from 5% above to 5% below the trip notpoint until the turbino la no tripped.
Section 12.2 discunnon the uno of an AMSAC signal delay h@
to onouro that the RPS will provido the first trip signal.
Section 13.0 on pago 3-8 requiron the AMSAC signal adjustablo do:
dolay to have a range of 0-60 noconds.
ESo.
UE and WCNOC intend to moot the abovo requirements.
Twenty-J f vo (25 nocondo was chonon to allow a 5 cocond margin for sensor /o{octronico delay and still moet the 30 nocond MaMg Addicss: P 0. Box 149, St. Louis, MO 63160
f requirement.
This setpoint will be adjustable to allow changes to be made in accordance with any future guidance from the WOG.
2)
Will isolation devices be qualified in accordance with Appendix A to the SER for WCAP-108587
Response
AMSAC requires isolation between Class IE and non-Class IE circuits on the steam generator level inputs from the RPS and on the actuation outputs to the Balance of Plant-Engineered Safety Features Actuation System (BOP-ESPAS).
Isolated outputs on the instrument loop power supplies in the RPS isolate the steam generator level inputs to AMSAC.
Westinghouse qualified the power supplies as an isolation device in WCAP-8892-A.
The testing done meets the requirements of Appendix A and has been reviewed and approved by NRC.
The AMSAC outputs to DOP-ESFAS will be isolated using Struthers-Dunn 219 frame general purpose relays.
The Stru thers-Dunn Qualification Test Report demonstrates that the 219 frame general purpose relay qualifies as an isolation device and meets l
the requirements of IEEE 279-1971 and RG 1.75.
The Struthers-Dunn relays remained functional (rolay collo did not short, ground-out or open-circuit) as demonstrated by the l
speciflod environmental and functional testing per IEEE-323 after l
aging.
Thoroforo, relay f ailure is not postulated to be a credible common mode failure during the 40 year qualified life of theco rolays.
These relayn successfully passed diolectric strength functional testing.
Under this testing, a voltago potential of 2200 V rms (as determined per ANSI C37.90) was applied to tho l
relays between the coil and contacts, the coil and caso, and tho l
contacts and caso.
Thoro was no arc-over, flash-over or l
breakdown observed.
The potential applied during this testing l
well excoods the maximum credible fault potential present in the AMSAC cabinet.
The maximum credible fault is from the 125 VDC power supply to the AMSAC cabinet.
l In addition to the electrical isolation provided by the coil i
to contact configuration of those relaya, physical separation l
between the terminals for the class IE nido and the non-Claas IE l
01d 0 providen at leant 6 inches of air space or its equivalent in
(
tracking distanco by means of barriors.
The Struthors-Dunn Qualification Toot Report moots the requiroments of IEEE 323-1974 and IEEE 344-1975.
i The Class IE contacts will be poworod from DOP-ESPAS Clann IE circuito.
AMSAC providon DOP-ESPAS with a dry contact through the inolation rolay.
Since this is an on/of' devico, thoro will bo no oloctrical interforence propagating from the coil to the contacts which would af fect the Claca IE BOP-ESPAS circuito.
o 3)
Provide more detail relating to the AMSAC logic and IE/NON-IE interfaces (Figure 1).
Respons,e is a logic drawing depicting the Callaway and Wolf Creek AMSAC system.
Isolated inputs from the RPS enter the l
logic cabinet and are compared to the AMSAC steam generator water level setpoint.
These signals are processed through a 3 out of 4 logic gate and are delayed 25 seconds to permit RPS actuation prior to initiating any AMSAC function.
Turbine impulse pressure signals are input to block AMSAC below 40% power.
Three logic schemes are connected in a 2 out of 3 configuration to protect l
against any inadvertent actuation.
l l also indicates the Class IE/non-Class IE l
interfaces.
Input isolation is provided by the RPS power l
supplies in the Westinghouse 7300 Process Protection System cabinets.
Output isolation is provided by Struthers-Dunn i
isolation relays.
4)
Will dif ferent power levels af fect the steam generator level transmitters?
nonponse l
l The Callaway and Wolf Creek plants employ a constant water l
level control scheme.
The control system maintains a 50% steam generator narrow range water level at any power level.
In addition, the level transmitters used by AMSAC are different than those used to control steam generator level.
If you have any further questions, please contact us.
Very truly yours, i
p/t 4
Donald F. Schnell GGY/ dis l
Attachment l
l l
4 h
f cc Gerald Charnoff, Esq.
Shaw, Pittman, Potts & Trowbridge 2300 N. Street, N.W.
Washington, D.C.
20037 J. O. Cermak CFA, Inc.
4 Professional Drive (Suite 110)
Gaithersburg, MD 20879 W. L. Forney Division of Projects and Resident Programs, Chief, Section lA U.S. Nuclear Regulatory Commission Region III 799 Roosevelt Road Glen Ellyn, Illinois 60137 Bruce Little Callaway Resident Of fice l
U.S. Nuclear Regulatory Commission RRil Steedman, Missouri 65077
[
Tom Alexion (2)
Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission l
Mail Stop 316 7920 Norfolk Avonuo Bothonda, MD 20014 l
Manager, Electric Department Missouri Public Service Commission P.O. Box 360 Jofferson City, MO 65102 l
l h
L I
(
ATIACBMENT L
as m
AMsAc.--.7,,
@x^*us i
1 26~S42:: og D(M
~~w g
g u
>I 6_gih
_rc t
i sg1
,u fn i ii
-!a
~ ~ -
DusM
- C un 126 sec
^*^Y 1sm.Arnw p
CDNof5Asus);
l I
I
\\
l'A ruaw t'R 1
r zsvuise I
,Q MMunC l
i t
I ar e a i-I l
l wy annaww I
o nw 3
'ZSerA r3 ant" l
t' f
i
<j j
f
//
1xaAyi r
i a
N
,A FA s o seay we i
i, l
L:.!
M
,v i
I t
j t
I i
I I
+t,:'
t 25 sec on t
i MY I,,
j i
i i
h 34 a
I snew z<<w=w m n,.,,,
AELAY Ei g
i: :
Z w beAy M
1 I
O t
N A
l e
/
DJ t
a