ML17352A507
| ML17352A507 | |
| Person / Time | |
|---|---|
| Site: | Turkey Point  |
| Issue date: | 03/29/1994 |
| From: | Plunkett T FLORIDA POWER & LIGHT CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-89-10, L-94-60, NUDOCS 9404070303 | |
| Download: ML17352A507 (8) | |
Text
. ACCELERATED DOCUMENT DISTRIBUTION.SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9404070303 DOC.DATE: 94/03/29 NOTARIZED: NO FACIL:50-250 Turkey Point Plant, Unit 3, Florida Power and Light C 50-251 Turkey Point Plant, Unit 4, Florida Power and Light C AUTH.NAME AUTHOR AFFILIATION PLUNKETT,T.F.
Florida Power 6 Light Co.
RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
DOCKET g
05000250 05000251 D
SUBJECT:
Responds to NRC 931118 ltr re concerns noted in Insp Repts 50-250/93-25 6 50-251/93-25 re util implementation of MOV program in response to GL 89-10.
DISTRIBUTION CODE:
A064D COPIES RECEIVED:LTR ENCL SIZE:
TITLE: Response to Generic Ltr 89-10, "Safety-Related MOV Testing 6
NOTES
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Surveill RECIPIENT ID CODE/NAME PD2-2 PD INTERNAL: AEOD/DSP/ROAB NRR/DE/EMEB NJRR/D W/OGCB EG FI Ol ES/DS
/EIB/B RNAL: NRC PDR COPIES LTTR ENCL 1
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1 RECIPIENT ID CODE/NAME CROTEAU,R AEOD/DSP/TPAB NRR/DRIL/RPEB NRR/PD111-3 RES/DSIR NSIC COPIES LTTR ENCL 1
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D NOTE TO ALL"RIDS" RECIPIENTS:
e PLEASE HELP US TO REDUCE WASTE} CONTACI'HE DOCUMENT CONTROL DESK,
'OOM P1-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!
TOTAL NUMBER OF COPIES REQUIRED:
LTTR 13 ENCL 13 D
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~
FPL MAR g 9'1SSr L-94-60 10 CFR 50.4 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.
C.
20555 Re:
Turkey Point Units 3 and 4
Docket Nos.
50-250 and 50-251 Safety-Related Motor-Operated Valve Testin and Surveillance Generic Letter 89-10 Nuclear Regulatory Commission (NRC) Inspection Report (NIR) 50-250/93-25 and 50-251/93-25 dated November 18,
- 1993, documented the results of the NRC inspection conducted to evaluate Florida Power and Light Co.'s implementation of the Turkey Point Units 3 and 4 Motor-Operated Valve Program in response to the recommendations of Generic Letter 89-10, "Safety Related Motor Operated Valve (MOV) Testing and Surveillance."
During the inspection, the NRC identified an industry concern regarding the proper operation of MOVs equipped with electric brake assemblies at degraded voltage conditions.
As requested by NIR 50-250/93-25 and 50-251/93-25, the attachment to this letter provides the response to the concern.
Should there be any questions please contact us.
Very truly yours,
~/
T. F. Plunkett Vice President Turkey Point Plant TFP/OIH cc:
Stewart D. Ebneter, Regional Administratoz, Region II, USNRC T. P.
- Johnson, Senior Resident Inspector,
- USNRC, Turkey Point Plant t
9404070303 940329 PDR (.~ ADOCK 05000250 a.... PDR=
an FPL Group company
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Attachment Page 1 of 2
ATTACHMENT BACKGROUND NRC Inspection Report (NIR) Nos.
50-250/93-25 and 50-251/93-25 documented the results of the NRC inspection conducted to evaluate Florida Power and Light Co.'s implementation of the Turkey Point Units 3 and 4 Motor-Operated Valve Program in response to the recommendations of Generic Letter 89-10, "Safety Related Motor Operated Valve (MOV) Testing and Surveillance."
During the inspection, the NRC identified an industry concern regarding the lack of documentation to support the operation of valve actuator motor brake assemblies at less than 90 percent of rated voltage.
The following discussion addresses this issue.
DISCUSSION Motor brakes are installed on the following nuclear safety zelated motor-operated valves (MOV's):
Motor-Operated Valve MOV-3(4)-716A MOV-3(4)-716B MOV-3 (4) -730 MOV-3 (4) -872 MOV-3 (4) -880A MOV-3 (4) -880B MOV-3 (4) -865A MOV-3 (4) -865B MOV-3 (4) -865C Function Reactor Coolant Pump (RCP)
Component Cooling Water (CCW) Supply Isolation Reactor Coolant Pump (RCP)
Component Cooling Water (CCW) Supply Isolation RCP Oil Cooler CCW Return Isolation Alternate Low Head Safety Injection (SI) to Cold Legs Containment Spray Pump Discharge Isolation Containment Spray Pump Discharge Isolation SI Accumulator Discharge SI Accumulator Discharge SI Accumulatoz Discharge The MOV's with brakes utilize spring engaged friction discs to decelerate the motors after motor de-energization.
Upon energization, an electromagnet overcomes the spring force on the friction discs, disengaging the brake.
The motor brakes were originally intended to minimize the inertial loads that may be seen during valve seating.
However, Limitorque has stated that the motor brakes do not significantly reduce valve stem thrust during valve seating.
Additionally, these MOV's have locking worm gear sets and do not require the motor brake to maintain the valves in a closed or throttled position.
t It was determined that MOV-3(4)-865A, B, and C do not perform active safety related functions.
MOV-3(4)-865A, B and C are normally open with their motor control center (MCC) breakers locked open during
4 ~
Attachment Page 2 of 2 power operation.
These MOV's are closed by remote manual action following a LOCA in order to block nitrogen entry into the Reactor Coolant System (RCS).
However, this remote manual action is not a safety related function since it is not essential for accident mitigation or safe shutdown.
Therefore, operation of the SI accumulator discharge valves'otor brakes is not required to fulfill a safety function.
The above listed MOV's are powered from 480 VAC MCC's.
Rated MOV voltages were conservatively assumed to be 460 VAC.
Verified nameplate information has shown that the valve actuator motors for the MOV's listed above are rated for 440 VAC operation.
Because the motor brake is designed to operate at the rated voltage of the motor, proper operation of the brake is expected at a voltage of at least 90 percent of rated, or 396 VAC.
The minimum calculated terminal voltages for the affected MOV's with active safety related functions have been determined to be 406V, which is greater 396 VAC (i.e.,
90% of rated voltage).
Therefore, operability of the MOV's equipped with brake assemblies under degraded voltage conditions has been verified.
CONCLUSION As discussed
- above, MOV's equipped with motor brakes which perform an active safety related function have been verified to have greater than 90 percent of rated voltage available during starting, Therefore, sufficient voltage will be available to operate the motor brakes under degraded voltage conditions.
In addition, the motor brakes for all the above MOV's will be disabled during the next refueling outage foz each unit.
The next refueling outage for Turkey Point Unit 3 is scheduled for April 1994.
The next refueling outage for Turkey Point Unit 4 is scheduled for October 1994.