ML19317G829
| ML19317G829 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 05/16/1977 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8004010657 | |
| Download: ML19317G829 (10) | |
Text
exs avce ascu'A s.
,on 19s
, i$C DISTRIBUTION FoR PART 50 DOCKET MATERIA'L
^ '
,P FROM:
DATE CF occuMENT 5/16/77 TO:
Sacramento Municipal Util.ity Dist.
Mr. Robert W. Reid Sacramento, California DATE RECEIVEo J. J. Mattimoe 5/19/77
. M T' ten ONOTORIZED PROP INF'.1T FORM NUMBER OF COPIES RECEIVED f j (;A) f D Mmomas.
ACLAss:FiE o Ccoes ENCLOSURE DEscHIFTeoN Ltr. trans the following:;
Response't'o NRC request-for-information regarding em,ergency dieseT' generator ' alarm and c9ntrol circuitry - D ted March,28, 1977..
~
' DDNOT EY:
1
.y ACI$70gLg)h'[
(-
( *-"
I'LANT NAME:
Rancho Seco Unit. No 1 O
RJL h
c, y g dMC SAFETY FOR ACTION /INFORMATION vm7Tu n
_\\ /,SSICNED.'.D:
AsSIGNen An.
_' 3RAN.CH CHIEF!
fei d (6)
RnANm mTre.
/ PROJE_CT l'A1AGER:
INCfson.
PROJECT PANAGER:
181 A rei M LIC. ASST. :
/ LIC, ASST. :
l INTERNAL DISTRt BUT*1CN DU rv4 _)
SYSTEMS SAFETY PLANT SYSTEMS SITE SAFETY &
REG FILE HEINEMAN TEDESCO ENVTRO AtlATYSTS
/ I & E (~2 )
CCHROEDER BENAROYA DEllION & "1RTIR f OELD f_ATNAR GOSSICK & STAFF ENGINEERING IPPOLITO EPJIRO TECR.
MIPC MACARRY KIRKWOOD ERNST CASE BOSHAK BALLA,RD
/ HANAUER SIHWEIL OPERATING REACTORS YOUNC3LOOD HARLESS PAWLICKI STELLO SITE TECH.
PROJECT MANAGEMENT REACTOR SAFETY OPERATING TECH.
CAMMILL j
BOYD ROSS
/
EISENHUT STEPP P, COLLINS NOVAK
/> SHAO HULMAN HOUSTON ROSETOCZY
/.
BAER PETERSON CHECK
/
BtJII.ER SITE ANALYSIS MELTZ
/
CRIMES VOLLMER BUNCH HELTEMES AT & I
/ J. COLLINS l
SKOVHOLT SALTEMAN KREGER J
R1ITBERC EXT RNAL DISTRIBUTION CONTROL NUMBE9 l
~
LPDR! Secka menfo, C4 NAT d AB:
DEQQK11AYSLEAI. LATL
_ TIC
/ REGlIE ULRIKSON (ORNL) 6 d
Z ACRS no CvS
- wee 3 r d. ULTANIS: score ov v+ oeot> >)
[
If NSIC:
^ SIB:.,
COE m __
/
g h
C,
,).
gSMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT O 6201 s street, Box 15830, Sacramento, Califomia 95813; (916) 452-3211 May 16,1977
!,.7,,,, y,,- y 7 r y
CU.jdUniWbM$UllUbef'
[ *g' g
Director of Nuclear Reactor Regulation I
u,,44yJg 197/m 7 At L ntion: Mr. Robert W. Reid, Chief Operating Reactors, Branch 4 U. S. Nuclear Regulatory Comission ma y
Washington, D. C.
20555 8
l/
D Docket No. 50-312 fn\\
Rancho Seco Nuclear Generating Station, Unit No.1
Dear Mr. Reid:
Please refer to your letter of March 28, 1977 wherein you re-quested that the District investigate the Rancho Seco Unit No.1 nuclear generating plant regarding the alarm circuitry and diesel generator con-trol circuitry to determine how each condition that rendcr5 a diesel generator unable to respond to an automatic start is.iarmed in the Control Room.
Enclosed with this letter are 40 copies of our response to the information request items on Page 2 of your letter.
Sincerely yours,
. l-J. J. Mattimce Assistant General Manager and Chief Engineer Enclosures l
A P.
ELECTRIC SYSTEY SERVING ?.10 R E THAN 600.000
'N THE HEART OF r, A i ! f o P 'i f A
m 3
(
SACRAMENTO MUNICIPAL UTILITY DISTRICT RANCHO SEC0 NUCLEAR GENERATING STATION, UNIT N0. 1 RESPONSE T0:
NUCLEAR REGULATORY COMMISSION REQUEST FOR INFORMATION REGARDING EMERGENCY DIESEL GENERATOR ALARM AND CONTROL CIRCUITRY DATED M'RCH 28, 1977 l
a May 16, 1977
m 9
NRC REQUEST FOR INFORMATION I.
NRC Question (a):
All conditions that render the diesel generator incapable of responding to an automatic emergency start signal as discussed above.
Response
A.
Physical parameters, the loss or degradation of which would prevent j
an automatic safety features initiated diesel engine start.
1.
Loss of or low DC voltage for the engine automatic start-up
~
control circuit.
2.
Loss of or low starting air pressure.
3.
Loss.of fuel oil from day tank.
4.
Loss of combustion air caused by the discharge o# the CO2 fire protection system.
(NOTE: A safety featunas actuation signal blocks the automatic C02 discharge system.)
B.
Protective devices, the operation of which would. prevent an auto-matic safety features initiated diesel engine start.
1.
Mechanical overspeed trip mechanism.
2.
Generator differential and field ground protective auxiliary i
relay.
3.
Failure to start trip relay circuit.
(NOTE: This protection t
would only effect second and subsequent attempts of an auto-matic start. An initial start has to be attempted and have failed before this circuit is activated to block subse automatic starts until the circuit is manually reset.)quent C.
Conditions which would prevent a buildup of generator voltage:
1.
Loss of or low DC supply voltage to the generator excitation system control circuits.
2.
Mechanical overspeed trip mechanism tripped.
3.
Generator differential and field ground protective auxiliary relay tripped.
D.
Control switches, the position of which would impair the ability of the engine speed governor and generator voltage regulation systems to automatically regulate the generator output frequency and voltage within the specified limits under loading conditions.
4 s
enn
.ra
.w n-n-..
-~s,
,,-,,e
,n,
-sm.e e--..,~w-n--,n
,~,-v,
o
')
l NOTE:
The position of these switches will not effect the automatic starting system for the diesel engine.
1.
Electric governor speed droop control switch.
2.
Automatic voltage regulator control switch.
E.
The " Local-Remote" control switch, the position of which would block a manually initiated automatic start from the i.nain control room.
NOTE:
The position of this switch would not block an automatic safety features initi-ated start of the diesel engine nor would it effect the normal operation of the engine speed governor or generator voltage regulator.
II.
NRC Question (b):
The wording on the annunciator window in the c'ntrol room that is alarmed for each of the conditions identified.a (a).
Response
All of the conditions listed above in the response to Question (a) are annunciated in the main control room on one or more annunciator windows.
The window engraving and alarm condition association is as follows:
NOTE The "A" and "B" diesel generator unit alarms are on separate annunciator windows.
The engraving for the Unit "B" alarms are in parenthesis.
Electrical system annunciator window engraving:
"DSL GEN A TROUBLE"
("DSL GEN B TROUBLE")
The following abnormal conditions are connected to initiate illumination
~
of this window:
?
[
)
O
, Item ~
Condition Al Loss of DC power to engine control circuits A2 Low starting air pressure A3 Low fuel oil level in day tank B1 Mechanical overspeed device tripped B2 Generator differential and field ground protective auxiliary relay tripped B3 Failure to start lockout relay circuit C1 Loss of DC power to excitation system control circuits C2 Mechanical overspeed device tripped C3 Generator differential and field ground protective auxiliary relay. tripped D1 Governor speed droop control switch in the " Droop" position D2 Automatic voltage regulator control switch in the. " Manual" position Electrical system annunciator window engraving:
"DSL GEN A AVR ON MAN OR L/R ON LOC"
("DSL GEN B AVR ON MAN OR L/R ON LOC")
The following abnormal conditions are connected to initiate illumination of this window:
Item Condition D2 Automatic vo'.tage regulatory control switch in the manual position E
Local-Remote :ontrol switch in the local position Fire protection annunciator window engraving:
" ZONE 40 AUX BLDG GRADE N DSL RM"
(" ZONE 41 AUX BLDG GRAPE S DSL RM") - Item A4, discharge of the CO2 system into the diesel generator room will. initiate illumination of this window.
j a
,,g.
_ v r
O
' Electrical system annunciator window engraving:
"125 V DC BUS FAILURE" Low voltage on either of the "A" or "B" safety features batteries will initiate illumination of this window.
Electrical system annunciator window engraving:
"125V BUS A TROUBLE"
("125V BUS B TROUBLE")
A trip of the DC control power supply circuit breaker for the emergency diesel generator control circuits will initiate illumination of this window.
III.
NRC Question (c):
Any other alarm signals that also cause the same annunciator to alarm.
Response
The above stated annunciator windows will alarm for the following additional conditions:
For the annunciator window which reads "DSL GEN A TROUBLE" ("DSL GEN B TROUBLE"), the fol. lowing additional items activata this window:
1.
High crank case pressure 2.
Air intake vacuum high 3.
Water temperature high 4.
Water temperature cold 5.
Standby oil pressure low 6.
Lube oil level low 7.
Lube oil temperature high 8.
Lube oil temperature low 9.
Lube oil filter differential pressure high
- 10. Lube oil bypass filter relief valve open
- 11. Fuel oil differential pressure high
- 12. Fuel oil filter bypass open
- 13. Fuel oil tank level high
- 14. Turbo charger exhaust temperature high
- 15. Air motcr start attempt failure
- 16. Fuel oil storage tank level low
- 17. Engine bearing temperature high
- 18. Encine room temperature high
- 19. Lube oil bypass pressure low
- 20. Combustion air pressure low
- 21. vacket water flow low 22.' Lute oil pressure low
s'.~
q p
u:
5-4
- 23. Engine fuel pump failure
- 24. Motor driven fuel pump failure
- 25. Fuel ptsnp pressure low i
- 26. Governor speed low
- 27. Generator overvoltage
- 28. Generator undervoltage
- 29. Generator field ground alann
- 30. Generator high stator temperature
- 31. Generator high bearing temperature
- 33. Generator low voltage Rectifier No. 2 failure
- 34. Generator circuit breaker protective relay trip For the annunciator window which reads "DSL GEN A AVR ON MAN OR L/R ON LOC" or ("DSL GEN B AVR ON MAN OR L/R ON LOC"), there are no additional alarm signals connected to activate this window.
For the annunciator window which reads " ZONE 40 AUX BLDG GRADE N DSL RM" or (" ZONE 41 AUX BLDG GRADE S DSL RM"), the following additional items activate this window:
1.
CO2 system trouble 2.
Discharge of fire water system For the annunciator window which reads "125V DC BUS FAILURE," low battery voltage alarm relays from the remain'ng five 125-volt batteries in the plant are connected to activate this window.
For the annunciator window which reads "125V BUS A TROUBLE" or (125V BUS B TROUBLE"), a trip of any other feeder breakers connected to this bus will activate this window.
IV.
NRC Ouestion (d):
Any condition that renders the diesel generator incapable of responding to an automatic emergency start signal which is not alanned in the control room.
Response
Within the scope of this review we consider that all of the conditions listed above in the response to NRC Question (a) includes all of the operational type conditions which would render the diesel generator incapable of responding to an automatic start signal (or responding to step load requirements in regard to frequency and voltage regula-tion). All of the above stated conditions are presently alanned in the control room in the manner described above.
The scope of this review covered the following systems:
e
,m o
e-,
-,a
~-, ~
-m n
p 6-i 1.
The electrical control circuitry for the automatic starting sequence of the engine.
2.-
The electrical control circuitry provided for manual maintenance starting, operating and testing of the diesel generator units.
3.
The electrical control circuitry for the generator excitation and voltage regulation systems.
1 4.
The protective shutdown circuits for the engine and generator.
5.
The speed governor electrical-control system.
- 6.. The alarm system for the emergency engine generators.
In making this review, the following initial condition assumptions were made:
1.
All supporting systems and equipment, valves, governor adjustments, voltage regulator adjustments, etc., are properly aligned, 2.
There are no abnormal or defective mechanical or electrical components or systems the failure or abnonnal operation of which could not be detected without actually attempting to start or operate the emergency generating units.
3.
The diesel generator unit had performed satisfactorily on its last automatic start test and no work had been done on the units since the performance of the test.
V.
NRC Question (e):
j Any proposed modifications resulting from this evaluation.
Response
We propose to make the following modifications to the diesel generator annunciator system:
1.
The annunciator windows that are presently engraved "DSL GEN A j
AVR ON MAN OR L/R ON LOC" or ("DSL GEN B ON MAN OR.L/R ON LOC")
will be reengraved to read as follows:
"DSL GEN A AUTO START IN0PERABLE"
("DSL GEN B AUTO START INOPERABLE")
2.
The diesel generator annunciator circuitry will be rewired so that the following conditions will cause activiation of the reengraved whdows:
i
+
,,r
(
. A.
Loss of DC power to the engine or generator control circuits.
B.
Low starting air pressure.
C.
Low fuel oil level in the day tank.
D.
Mechanical overspeed trip device in the tripped position.
E.
Generator differential and field ground protective auxiliary relay tripped.
F.
Fail to start relay circuit tripped.
G.
Electric governor speed droop control switch in the droop position.
H.
Automatic voltage regulator control switch in the manual position.
I.
Local-Remote control switch in the local position.
l
- J.
Engine lube oil level low.
- A low (or loss of) engine lube oil condition would not block an automatic start of the engine; however, because the condition could result in failure of the engine shortly after starting, we consider it highly desirable to add this alarm to this group.
e 4
,e
-,