ML19210A376
| ML19210A376 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/12/1977 |
| From: | Arnold R METROPOLITAN EDISON CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| GQL-0632, GQL-632, NUDOCS 7910290604 | |
| Download: ML19210A376 (6) | |
Text
NRCrom l'
W.S. NUCLE AR REGULATORY CoMMISSICN OoCKET NUMnf o
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t NRC DISTRIBUTION FoR PART 50 DOCKET MATERI AL TO.
FROM:
oATE of occWMENr Metropolitan Edison Company 5/12/77 Mr. R. W. Reid Reading, Pa.
oars AgCgivso R. C. Arnold 5/18/77 NTTE R ONoToRizEo rRo*
iNeuTroRu NUMBER oF COPIES RECEaVEo pOCoev gNeL4Ssi,,c o f g7/.G A).h iceN AL DESCRIPfeoN ENCLOSURE Ltr. trans the following:
Consists of information concernin2,the alarm j
circuitry and diesel generator control.'
circuitry for'the diesel g ne,rators at Unit No.
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PLANT NAME:
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[h Three Mile Island Unit No. 1 RJL SAFETY FOR ACTION /INFORMATICN rWTon 6
ASSIGNED AD:
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Dear Sir:
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Cn March 26, 1977, you sent a letter requesting a reply, in forty-fiv days, to five questions concerning the alarm circuitry and diesel generator contrcl circuitry for the diesel generators at Three Mile Island :Juelear Station, Unit 1.
Attached is our response to these questions. Should you have any further questions, please contact either myself or Mr. D. G. Mitchell (ext. S8-169).
Sincerely, R. C. Arnold Vice-President RCA:rGM:bar Attachments 1469 035
RCEERT '.i. REID Attachment page 1 Metropolitan Ediscn Ccmpany GQL Co32 C/M
/I' '"l s /
4-Backgrounc The NRC has requested that a review of the alar: ind control circuitry for the diesel generators be conducted to determine how any condition that renders a diesel generator unable to respcnd to an autetatic emer-gency start signal is alarmed in the Centrol Rocm. This review is to consider all aspects of possible diesel generator operational conditions, including tests 2nd local control operations. Specifically, the 3RC has requested:
a) All conditions that render the diesel generator incapable of respcnding to an autenatic emergency start signal.
b) The wording en the annunciator window in the Control Rccm that is alarmed for each of the conditicns identified in (a).
c) Any other alarm signals that also cause the same annunciator to alarm.
d) Any condition that renders the diesel generator incapable of responding to an automatic emergency start signal which is not alarmed in the Centrol Rocm.
e) Any proposed =cdificatiens resulting from this evaluation.
Cenclusion It has been determined frcm this review that the information available to the Control Room can be confusing and scce informaticn 10 not available to the operatcr. This is caused by the sharing of a single annunciator in the Control Ro c by all the alarms on the local alarm panel.
Sc=e af the local alarms are disabling while the others only indicate an abnormal, but not disabling condition. Also, whenever any one of these local alarms is annunciated in the Centrol Rocm, any other conditicn that is alarmed will not be annunciated in the Centrol Roca because this annun-ciator does not have a reflash capability. The attached Table A provides the information required for items a, b and c of the :TFC request.
For item d, the only ecndition that is not presently alarued, but would render the diesel generator unable to respond to an autccatic energency start signal, vculd be the exciter centrol circuitry not in the reset condition.
If the exciter reset is not operated after local testing, the exciter field cannot be flashed on a subsequent start, preventing the diesel generator frc: generating the required Icad.
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RCEERT '4.
REID Attachment page 2 Metropolitan Ediscn Oc=pany GC1 0632 5 / 12 /7 7 The proposed =adificatiens to both A and E diesel generators are:
1.
Change the Control Rec = annunciation as cutlined in the attached Table 3.
2.
Add a new alar =, Exciter.Ict Reset, to the 1ccal alar = panel in the spare window slot. This alar = vould in turn annunciate in the Control Roc = cn the associated Diesel Generator Elceked annunciator.
3.
Add a reflash capability to the Control Roc = annunciator, Diesel Generator Trouble Alarms.
Tentative date for ec=pletion of modi +1caticns is the next scheduled refueling outage - 1978.
Discussion The present system of alarming conditicns that render a diesel ganerator unable to respond to an automatic emergency start signal can be mislead-ing and confusing. The proposed modifications will better inform the Centrol Rec = cperator of the status of the diesel generators. The Control Roc = cperator vill be able to =cnitor the status all the time, and will be able to determine if the diesel generator has been restcred to the proper operating mode after tests or local control operations.
Also, the opereter vill be informed whenever =cre than ene alar = condition exists with the reflash capability instead of the current mode of the first alar annunciating and subsequent alar =3 not annunciating in the Control Roc =. This vill prevent maintained spurious alar s frc= disabling the annunciator.
1469 037
HOBERT W. fWID Attachment Page 3 Metrooclitan Edison Comptiny A
A o b 0632 5/12/77 ltem a - CEJITions that render the diesel generator Item b - Wording on the Annun-Ttem e - Any other alarm signalu incapable of responding to an automatic emergency ciator Window in Control Hoom that also cause the swue annun-start signal.
that is alarmed, clator to alarm.
l.
Selector Switch (<.3) in Control Hoom not in Diesel Gen. Blocked Either diesel gen,, lA or lb, the automatic (standby) position.
will alarm. (1) 2.
Control Switch at engine panel not in the "!!or-Dies 61 Gen. Trouble Any one -f 19 alnrms from local (2) mal" position (Annun. B/1-5 for l A, al ur.n une. in diesel gen. room 3.
Diesel Gen. Breaker Lockout Relay Diesel Gen lA/lB Gen.
Either geselgen.,
lA or lb wil Bkr. Locked-Out alarm from local h.
Overspeed Trip Helay energized - caused by Diesel Gen. Trouble Any one of Iglarms overspeed or diesel fuel rack not engaged alarm pune' S.
Starting Air Pressure Low - air pressure Diesel Gen. Trouble Any one "d
arms from local less than 150#
alarm pau 1 (L) 6.
Shutdown Relay energized by any of the Diesel Gen. Trouble Any one of 19 a ms from local following - lube oil pressure low (2 out of alarm panel (')
3 pressure switch matrix
- i. Manual Air Valve Ilot Open Diesel Gen. Trouble Any one of 19 alains from local alarm panel (2)
Ih1TES :
1.
Data Logger differentiates which diesel caused alarm.
2.
Local Alarm Panel Alarms are: 1) Lube Oil Pressure Low, 2) Lube Oil Temp. Low, 3) Lube Oil Level Low, h ) Jacket Coolant Temp. Ilic't, S) Jacket Coolant Press. Low, 6) Jacket Coolant Level Low, '() Fuel Oil Day Tank Iligh or Low,
- 8) Fuel Oil Pressure Low, 9) Starting Air Pressure Low, 10) Starting air manual valve closed, 11) Start Failure,
- 12) Overspeed, 13) Engine crankcase pressure, lb) a switch not in automatic (accessory e<p:1pment),15) Field ground, 16) Gen. Bkr. open, 17) D.
C.
fuel oil pump operating, 18) control fuse fai l u re, 19) Mtintenance shutdown.
3.
Data Logger di f rerentiates which diesel caused alarm.
M 4
CD tra 00
At tachraent ROBERT W. REID p"E" i' f4etropolitan Edison Co.
TABLE B GQL 0632 S/12 /77 Existing Control Hoo7 Change Annun. Wording To Head Conditions Which Will Alarn This Annunciat,or Annunciator Wording l.
Diesel Gen. Blocked Diesel Cen. A Blocked 1.
Selector Switch flot in Auto 2.
Control Switch flot in fiormal 3.
Shutdown Helay Energized b.
Start,ing Air Pressur-Low 5
StartingAirflanuagalveClosed 6.
Exciter flot Reset 7
Gen. hkr. Locket-Out 2.
Diesel Gen. bkr.
Diesel Gen. B. Blocked Same as item 1.
by any one of 16 local alarms { g prevent blocking Provide rerlush on this alarm 3.
Diesel Gen. Trouble flo change to Wording LA 4.
Diesel Gen. Trouble Ilo Change to Wording P ovide rerlash on this algrp to prevent blocking by 18 any one or 16 local alarms flOTES :
1.
The following existing local alarms would be modified to alarm Diesel Gen. Blocked annunciator:
a.
St,arting Air Pressure Low b.
!4anual Air Valve Closed e,
14alitenance Shutdown The following existing local alarms would continue to alarm Diesel Gen. Trouble annuneintor but with rerlash capabiLit.y:
a.
Lube Oil Press. Low 1.
Start Failure b.
Lube Oil Temp. Low
- j. Engine Crankease Pressure c.
Lube Oil Level Low k.
A switch not in auto. (accessory equip.)
P'"
d.
Jacket Coolant Temp. liigh 1.
Field Ground e.
Jacket Coolant Press. Low m.
Gen. bkr. Open f.
Jacket Coolant, Level Lov n.
D.
C.
Fuel Oil Pump Operating g
g g.
Fuel Oil Day Tank High or Low o.
Control Fuse Fr.ilure w
h.
Fuel Oil Press. Low p.
Ove rspeed 2.
Ilew alarm to be added to Spare position on Local Panel to alarm Diesel Gen. Blocked annunciator.