ML17262A815
| ML17262A815 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 04/09/1992 |
| From: | Mecredy R ROCHESTER GAS & ELECTRIC CORP. |
| To: | Andrea Johnson NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation |
| References | |
| TASK-09-03, TASK-9-3, TASK-RR NUDOCS 9204170148 | |
| Download: ML17262A815 (17) | |
Text
ACCELERATED DISTRIBUTION DEMONSTPA.TION SYSTEM
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REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ESSION NBR:9204170148 DOC.DATE: 92/04/09 NOTARIZED:
NO FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G
AUTH.NAME AUTHOR AFFILIATION MECREDY,R.C.
Rochester Gas 6 Electric Corp.
RECIP.NAME RECIPIENT AFFILIATION JOHNSON,A.R.
Project Directorate I-3
SUBJECT:
Forwards corrections to NRC 811104 SER re SEP Topic IX-3, "Svc Water 6 Cooling Water Sys," per Svc Water Sys Operational Performance Insp 50-244/91-201.More detailed calculations re post-accident heat loads underway.
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TITLE: Correspondence re SEP Topics NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72).
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41'9 EAST AVENUE, ROCHESTER N.Y. 14649-0001 ROBERT C MECREOY Vice President Ginna Nuctear Production April 9, 1992 TELEPHONE ArtwcooETie 546-2700 U.S. Nuclear Regulatory Commission Document Control Desk Attn:
Allen R. Johnson Project Directorate I-3 Washington, D.C.
20555
Subject:
SEP Topic IX-3, Service Water and Cooling Water Systems R.E.
Ginna Nuclear Power Plant Docket No. 50-244 Ref.
(a)
NRC letter, dated November 3, 1981, from Dennis M.
Cruthfield (NRC) to John Maier (RG&E), "SEP TOPIC IX-3, STATION SERVICE AND COOLING WATER SYSTEMSI GINNA
Dear Mr. Johnson:
As a result of discussions with NRC representatives during the Service Water System Operational Performance Inspection (NRC Inspection No. 50-244/91-201) at Ginna Station, RG&E agreed to advise your office of the need to clarify several items contained in the referenced SER.
A number of recommended
- changes, written from the perspective of a reviewer preparing the original SER, are suggested in Attachment A to this letter.
No changes are recommended to the NRC comments regarding the apparent inconsistency between what Service Water System arrangements are needed for long-term recirculation cooling, and what is required to be operable in the Ginna Technical Specifications.
As stated in Reference (a) above,..."this evaluation will be a basic input to the integrated safety assessment for your facility..."
RG&E's understanding was that proposed facility changes would be reviewed within the context of this overall Integrated Safety Assessment, not necessarily as a
result of each individual topic assessment (see NUREG-0821, Dec.
1983).
The Integrated Safety Assessment requested only that RG&E evaluate the power supply/pump arrangement, where potentially both operable Service Water (SW) pumps would be aligned to the same power supply.
This issue was resolved, as part of the NRC-approved License Amendment No. 11, July 30, 1985.
RG&E is presently in the process of performing more detailed analyses relative to post-accident recirculation heat loads.
Preliminary results indicate acceptable conditions prevailing
'Ti204170148 920409 j]Qf> I PDR ADOCK 05000244 P
PDR within containment and the CCW/RHR systems, using only one SW cr
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pump for both the post-LOCA injection and recirculation phases.
It is expected that this analysis can be completed, and an independent review performed, by the end of June 1992.
We will keep you advised of the schedule for this item and provide the results when completed.
Very truly yours, Robert C. Mecredy JCM/212 xc:
Mr". Allen R. Johnson (Mail Stop 14D1)
Project Directorate I-3 Washington.,
D.C.
20555 U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna Senior Resident Inspector
I
ATTACHMENT A R.
E.
GINNA STATION SEP TOPIC IX-3 "SERVICE WATER AND COOLING WATER SYSTEMS" Corrections to NRC SER contained in NRC letter dated November 3,
1981 from Dennis M. Crutchfield (NRC) to John E. Maier (RG&E)
CLARIFICATION NO.1:
(see page 3 of SER, section V.1. Component Cooling Water System, last paragraph)
Existin Wordin During normal plant operation, one CCW pump and one CCW heat exchanger are in operation, and they can accommodate the heat removal load on the system.
Both pumps and heat exchangers are normally used for a plant cooldown; however, if one pump or one heat exchanger is not operable, safe operation of the plant is not affected, but the time to cool the plant is extended (Reference 2).
CCW pump A and.
B receive electrical power from 480 V buses 14 and 16, respectively.
Recommended Wordin (proposed changes are underlined)
During normal plant operation, one CCW pump and at least one CCW heat exchanger are in operation, and they can accommodate the heat removal load on the system.
Both CCW pumps and both CCW heat exchangers are normally used for a plant cooldown; however, if one pump or one heat exchanger is not operable, safe operation of the plant is not
- affected, but the time to cool the plant is extended (Reference,2).
CCW pumps A and B receive electrical power from 480 V buses 14 and 16, respectively.
Page 1 of 8
ATTACHMENT A R.
E.
GINNA STATION SEP TOPIC IX-3 "SERVICE WATER AND COOLING WATER SYSTEMS" Corrections to NRC SER contained in NRC letter dated November 3,
1981 from Dennis M. Crutchfield (NRC) to John E. Maier (RG&E)
CLARIFICATION NO.2:
(see page 5,of SER, section V.1. Component Cooling Water System, third paragraph)
Existin Wordin No post-accident realignment of the CCW system is performed by the operator except for the opening of a CCW supply valve to one RHR heat exchanger at the start of recirculation and
- closing,
.or verifying the automatic closure of, the isolation valves to the service inside containment.
These actions can be performed from the control room.
Recommended Wordin (proposed changes are underlined)
No immediate post-accident realignment of the CCW system is performed by the operator except for closin or verif in the automatic closure of the containment isolation valves in the CCW lines servin the reactor su ort coolin ads the excess letdown heat exchan er and if necessar the Reactor Coolant Pum s.
At the start of recirculation ost-accident reali nment of the CCW s stem b the o erator consists of startin the second CCW um and o enin the CCW su 1
valves to both RHR heat exchan ers.
These actions can be performed from the control room.
Page 2 of 8
ATTACHMENT A R.
E.
GINNA STATION SEP TOPIC IX-3 "SERVICE WATER AND COOLING WATER SYSTEMS" Corrections to NRC SER contained in NRC letter dated November 3,
1981 from Dennis M. Crutchfield (NRC) to John E. Maier (RG&E)
CLARIFICATION N0.3:
(see page 6 of SER, section V.l. Component Cooling Water System, second paragraph)
Existin Wordin Loss of the CCW system during post-accident operation was considered in the Provisional Operating License review of
- Ginna, and it was concluded that the RHR pumps could continue to operate to recirculate containment sump water with decay heat being removed by the containment fan coolers.
However, because the CCW system cools the bearings and lubricating oil coolers for the RHR (and other ECCS)
- pumps, these pumps would not be available to recirculate the sump water.
Current criteria for piping system passive failures do not require the assumed passive failures of moderate energy systems (like the CCW) under post-accident conditions, although system leaks are assumed (Ref. 7).
Therefore, the CCW system makeup capability should be capable to cope with normal system leakage in post-accident operation.
Recommended Wordin
- (proposed changes are underlined)
Loss of the CCW syst: em during post-accident operation was considered in the Provisional Operating License review of Ginna.
Durin the in ection hase com onent coolin water is not essential to be su lied to the safet related um s for their mechanical seals (safet in ection um s containment s ra um s and residual heat removal um s or bearin water
'ackets residual heat removal um s) because the um ed fluid ori inates from the Boric Acid Stora e
Tanks and refuelin water stora e tank (RWST).
Durin the recirculation hase com onent coolin water is necessar to cool these com onents since the sum water tern erature is ex ected to be hi h (above 212 F).
This assumed continued o eration of CCW is acce table because current criteria for piping system passive failures do not require the assumed passive failures of moderate energy systems (like the CCW) under post-accident conditions, although system leaks are assumed (see Standard Review Plan Section 9.2.2).
The CCW system makeup capability should be capable to cope with normal system leakage in post.-accident operation.
Page 3 of 8
ATTACHMENT A R.
E.
GINNA STATION SEP TOPIC IZ-3 "SERVICE WATER AND COOLING WATER SYSTEMS" Corrections to NRC SER contained in NRC letter dated November, 3, 1981 from Dennis M. Crutchfield (NRC) to John E. Maier (RG&E)
CLARIFICATION N0.4:
(see page 15 of SER, section 3.0, REFERENCES)
Existin wordin 7.
Staff Discussion of Twelve Additional Technical Issues Raised by Responses to November 3,
1976 Memorandum from
- Director, NRR to NRR Staff, NUREG-0153, Issue
- 517, December 1976.
Recommended Wordin 7.
DELETED (note that Reference 7 only d'iscusses passive mechanical valve failures)
CLARIFICATION N0.5:
(see page 7 of SER, section V.2 Service Water System, first paragraph)
Existin Wordin The Service Water System (SWS) circulates water from the screen house on Lake Ontario to various heat exchangers and systems in the containment, auxiliary and turbine buildings.
These buildings are Class I structures except for the turbine building.
The system has four pumps, three of which are in operation during normal plant operating conditions.
As described in the previous CCW section, two SWS pumps are required to remove heat from components under post-accident conditions.
Recommended Wordin (proposed changes are underlined)
The Service Water System (SWS) circulates water from the screen house on Lake Ontario to various heat exchangers and systems in the containment, diesel enerator intermediate auxiliary and turbine buildings.
These buildings are Class I structures except for the turbine building.
The system, has four pumps, either two or three of which are in operation during normal plant operating conditions.
As described in the previous CCW section, lant service water load re uirements dictate that one SWS um is re uired durin the ost-accident in ection hase and that two SWS sum recirculation hase of post-accident conditions.
Page 4 of 8
ATTACHMENT A R. E.
GINNA STATION SEP TOPIC IX-3 "SERVICE WATER AND COOLING WATER SYSTEMS" Corrections to NRC SER. contained in NRC letter dated November 3, 1981 from Dennis M. Crutchfield (NRC) to John E. Maier (RGGE)
CLARIFICATION N0.6:
(see page 7 of SER, section V.2 Service Water
- System, second, paragraph)
Existin Wordin The SWS piping is arranged so that there are two flow paths to the redundant "critical"* loads identified in Table 2.
Another header supplies various "non-critical" loads (see Table 3).
The "non-critical" loads are automatically isolated from the "critical" headers by redundant motor operated valves when a reactor safeguards actuation signal occurs.
Redundant motor operated isolation valves also automatically secure SWS flow to the air conditioning chill water system, circulating water pumps, and screen wash supply on a safeguards actuation signal.
Recommended Wordin
- (proposed changes are underlined)
The SWS piping is arranged so that there are two flow paths to the redundant "critical"* loads identified in Table 2~
and to the "non-critical" Reactor Vessel Cavit Coolers and Containment Penetration Coolin loads listed in Table 3.
Branch headers su 1
various "non-critical" loads (see Table 3).
Redundant motor o crated valves are rovided to automaticall isolate the "critical" headers from., the CCW heat exchan ers the s ent fuel ool coolin heat exchan er and the "non-critical" headers.
The redundant valves within each air are owered from inde endent 480-V buses.
The motor o crated valves within each inde endent train will automaticall receive a close si nal followin a safeguards actuation signal concurrent with a tri of the normal su 1
breaker on their associated 480-V bus.
These valves will then close automaticall u on reener ization of their associated 480-V electrical bus b its diesel enerator.
Page 5 of 8
ATTACHMENT A R.
E.
GINNA STATION SEP TOPIC IZ-3 "SERVICE WATER AND COOLING WATER SYSTEMS" Corrections to NRC SER contained in NRC letter dated'November 3,
1981 from Dennis M. Crutchfield (NRC) to John E. Maier (RG&E)
CLARIFICATION N0.7:
(see page 8 of SER, section Ve2 Service Water System, first paragraph)
Ezistin Wordin During normal plant operation, the SWS supplies flow to all loads except the standby auxiliary feed-systems.
During RHR operation for a normal plant cooldown, almost all "non-critical" loads may be removed from the SWS, if necessary.
Following a safeguards actuation 'signal, the SWS supplies all "critical" loads except the backup feedwater supply to the auxiliary and standby auxiliary feed systems, which require operator action to receive SWS flow.
Recommended Wordin (proposed.
changes are underlined)
During normal plant operation, the SWS supplies flow to all l.
feedwater and standby auxiliary feedwater systems.
During RHR operation for a normal plant. cooldown, almost all "non-critical" loads may be removed from the SWS, if necessary.
Following a safeguards actuation signal (with bus undervolta e) the SWS continues to su l all receuired "critical" loads except the supply to the auxiliary feedwater s stem and the standby auxiliary feedwater
- system, which require operator action to receive SWS flow.
Page 6'f 8
ATTACHMENT A R.
E.
GINNA STATION SEP TOPIC IX-3
')SERVICE WATER AND COOLING WATER SYSTEMS" Corrections to NRC SER contained in NRC letter. dated November 3,
1981 from Dennis M. Crutchfield (NRC) to John E. Maier (RG&E)
CLARIFICATION N0.8:
(see page 8 of SER, section V.2 Service Water
- System, second paragraph)
Existin Wordin To overcome single failures in the system each "critical" load has a redundant counterpart cooled by the other "critical" SWS header.
If necessary, an operator could cross-connect the "critical" headers by means of manual valves to achieve added system flexibility. In the normal system alig'nment, no single active or passive failure could result in the loss of SWS flow to redundant "critical" loads except for the reactor vessel cavity coolers which could both be disabled by a single passive failure.
Since the SWS is a moderate energy system, a passive pipe failure would probably result in a leak rather than a complete pipe rupture.
Using the method described in Reference 5, the estimated leakage for a SWS header is 585 gpm for a 20" header at 75 psig.
Although this leak may cause a flooding
- problem, the supply function of the affected header would not be significantly impaired.**
A leak from the 2.5" supply line to the reactor cavity coolers would result in the loss of about 25 gpm.
This leak rate would not completely disable the coolers which normally receive about 45 gpm of SWS flow.
Recommended Wordin
- (proposed changes are underlined)
To overcome single failures in the system each "critical" load has a redundant counterpart cooled by the other "critical" SWS header.
If necessary, an operator could cross-connect the "critical" headers by means of manual valves 4610 and 4779 (in the 20-in su 1
loo s) to achieve added system flexibility. In the normal system alignment, no single active or passive failure could result in the loss of critical" reactor vessel cavity coolers could both be 1
SWS is a moderate energy system, a passive pipe failure would probably result in a leak rather than a complete pipe rupture.
Using the method described in Reference 5, the estimated leakage for a SWS header is 585 gpm for a 20" header at 75 psig.
Page 7 of 8
ATTACHMENT A R.
E.
GINNA STATION SEP TOPIC IX-3 "SERVICE WATER AND COOLING WATER SYSTEMS" Corrections to NRC SER contained in NRC letter dated November 3, 1981 from Dennis M. Crutchfield (NRC) to John E. Maier (RG&E)
CLARIFICATION N0.8:
(see page 8 of SER, section V.2 Service Water
- System, second paragraph)
Recommended Wordin
- (continued)
Although this leak may cause a flooding problem, the supply function of the affected header would not be significantly impaired.**
A leak from the 2.5" supply line to the "non-critical" reactor coolers would result in the loss of about 25 gpm.
This leak rate would not completely disable the coolers which normally receive about 45 gpm of SWS flow."**
- Since the ur ose of this review is to com are Ginna to the SRP such assive failures are discussed.
However the Ginna licensin basis for the Service Water S stem re uires that ost-LOCA o eratin re uirements are met assumin a
sin le active failure (AIF-GDC 41)
CLARIFICATION N0.9:
(see page 8 of SER, Table 2.
"CRITICAL SWS LOADS", item 7)
Existin Wordin Standby Fuel Pool Cooling Recommended Wordin (proposed changes are underlined)
~Sent Fuel Pool Cooling 0
Page 8 of 8
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