ML20045H966
| ML20045H966 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 07/12/1993 |
| From: | Denton R BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GL-89-13, TAC-M73978, TAC-M73979, NUDOCS 9307220192 | |
| Download: ML20045H966 (13) | |
Text
BALTIMORE
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GAS AND ELECTRIC 1650 CALVERT ClJFFS PARKWAY. LUSBY, MARYLAND 20657-4702 ROBERT E. DENTON July 12,1993 VicE PnEslDENT NUCLE An ENE'nGY (4 so) iso-e a ss U. S. Nuclear Regulatory Commission Washington,DC 20555 ATTENTION:
Document Control Desk
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 Summary of Completed Actions; NRC Generic Letter 89-13,
" Service Water System Problems Affecting Safety Related Equipment" (TAC Nos. M73978 and M73979)
REFERENCES:
(a)
NRC Generic Letter 89-13, dated July 18,1989, " Service Water System Problems Affecting Safety Related Equipment" (b)
Letter from Mr. G. C. Creel (BG&E) to NRC Document Control Desk, dated January 29, 1990, Response to NRC Generic Letter 89-13, same subject (c)
Letter from Mr. G. C. Creel (BG&E) to NRC Document Control Desk, dated September 16, 1992, Summary of Completed Actions; Generic Letter 89-13; same subject
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(d)
Letter from Mr. G. C. Creel (BG&E) to NRC Document Control Desk, dated January 6,1992, Revised Response to NRC Generic Letter 89-13, same subject (e)
Letter from Mr. G. C. Creel (BG&E) to NRC Document Control Desk, dated August 4,1992, Revised Testing Schedule, same subject (f)
NRC Generic Letter 89-13, Supplement 1, dated April 4,1990, same subject NRC Generic Letter 89-13, Reference (a), outlined concerns regarding the safe operation and maintenance of the Service Water (SRW) Systems and identified several recommendations associated with ensuring proper heat transfer capability of SRW System components.
Baltimore Gas and Electric Company's (BG&E) response to Generic Letter 89-13 was provided in Reference (b). In that response we outlined our planned actions and stated all initial activities will be completed before plant start-up (Mode 2) from the next refueling outages for each unit. This letter summarizes the Generic Letter 89-13 activities completed for Unit 2.
Reference (c) summarized the Generic Letter 89-13 activities that were completed for Unit 1 during the 1992 Refueling Outage. Portions ofit are repeated in this letter.
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Reference (b) outlined five tasks that would be performed to address the recommended actions of the generic letter.
TASK 1 SaltwaterIllofouline Procram All initial activities have been completed.
TASK 2 Test Procram The original commitment to test heat exchangers was revised in References (d) and (e).
Enclosure (1)is a summary of the initial test results. Generic Letter 89-13 requests us to implement the recommended actions or justify our alternatives to them. Enclosure (2) is a " Justification of Alternatives to Testing" requested in the Reporting Requirements of Generic Letter 89-13 page 7.
With the exception of performing baseline tests on the SRW Heat Exchangers, initial activities for Unit 2 are complete. Because of extensive modifications that would be made to the Saltwater System during the outage, we determined that baseline tests performed on them before the outage would not be representative of the system and would, therefore, add no value to the test program. As described in Enclosure (2), we are confident that these heat exchangers adequately perform their j
heat removal functions. These heat exchangers will be tested when they are taken out-of-service for their next quarterly tube bulleting.
In Reference (b), we committed to perform initial testing of our closed-cycle systems (SRW and Component Cooling Systems) to determine which heat exchangers should be included in the periodic test program. This commitment was a result of our inability to confirm the adequacy of our chemistry I
control program over the total operating history of the plant. Based on the results of testing and l
inspecting these closed-cycle systems, we have concluded the quality of our chemistry control program maintains adequate heat transfer capability. Future periodic testing of Unit 1 and 2 closed-cycle systems under the scope of Generic Letter 89-13 is not necessary and will not be performed.
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TASK 3 Inspection and Maintenance Procram All planned actions committed to in Reference (b) have been completed. All underground saltwater pipe was inspected. Repairs were made as necessary. The ultrasonic test program has been reviewed and revised.
TASK 41icensineIlusis Review The planned actions described in Reference (b) have been completed. System hydraulic and heat i
exchanger software models have been developed. The software was validated by duplicating a
'i number of BG&E hydraulic calculations and comparing the results to the original calculations.
System models were validated by comparison to actual plant data. Design Basis hydra ilic and heat transfer calculations have been validated. System drawings were reviewed and walkdowns were i
performed to ensure the systems were not vulnerable to single active failures.
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l Document Control Desk July,12,1993 Page 3 TASK 5 Service Water Systems Procram Review The planned actions described in Reference (b) have been completed with the exception of i
procedure upgrades. The Procedure Update Project is on schedule to complete the upgrades to the technical procedures by December 1994.
Having completed the initial actions described here for Units 1 and 2, we can confirm that our existing programs to maintain heat removal capability were adequate to assure accomplishment of the systems' safety functions.
Further, comprehensive effort found no new or unexpected degradation mechanisms.
Should you have any further questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours,
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2%c-for R. E. Denton Vice President - Nuclear Energy RED /JMOTjmo/ dim Enclosures cc:
D. A. Brune, Esquire J. E. Silberg, Esquire R. A. Capra, NRC D. G. Mcdonald, Jr., NRC T. T. Martin, NRC P. R. Wilson, NRC R. I. McIran, DNR J. H. Walter, PSC
Page 1 of 7 ENCLOSURE (1)
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IIEAT EXCIIANGER TEST PROGRAM IN TEST TEST TEST SYSTEM HEAT EXCHANGER PROGRAM TYPE RESUL'IS COMMENTE Component Cooling Y
I 21 & 22 SAT Tube side cleaned each quarter.
Heat Exchangers or S
21 & 22 II.B A
L T
W A
T Service Water Y
I Test postponed due Tube side cleaned each quarter. Test will be E
Heat Exchangers or to extensive pipe performed during next tube bulleting (fall 1993).
R 21 & 22 II.B modifications. See Enclosure (2) for details.
ECCS Pump Room Y
I 21 & 22 SAT Air side cleaned.
S Air Coolers III.A.
Y 21 & 22 or S
III.B T
E M
Intake Structure N
NA NA NA Air Coolers
. Page 2 of 7.
ENCLOSURE (1)
HEAT EXClIANGER TEST PROGRAM IN TEST TEST TEST SYSTEM HEATEXCHANGER PROGRAM TYPE RESULE COMMENE Containment Air Y
III.A.
21,22,23 & 24 SAT Air side cleaned.
Coolers 21,22,23,24 or III.B S
Spent Fuel Pool Y
ll.B.
11 & 12 SAT (1W2 No cleaning necessary.
E Cooling Heat Exchangers Refueling Outage)
R V
Diesel Generator Coolers Y
II.A 11 EDG Jacket Water Nos.11,12 & 21 EDG coolers are inspected at I
Cooler & Air Coolant 18-month intervals. Results have been SAT. All C
Heat Exchanger coolers are identical Testing Lube Oil Coolers is E
tested SAT.11 EDG not practical; however, inspections indicate there Lube Oilcooler has been no need to clean them. See inconclusive due to Enclosure (2) for details.
Iow oil flow W
A Main Feed Pump Turbine N
NA NA NA T
Lube Oil Coolers E
R EHC Oil Coolers N
NA NA NA Main Turbine Lube N
NA NA NA S
Oil Coolers Y
S Generator / Exciter N
NA NA NA T
Air Coolers E
M Stator Liquid Cooling N
NA NA NA Heat Exchangers (U-1)
Hydrogen Seal Oil N
NA NA NA Coolers (U-2)
Page 3 ef 7 ENCLOSURE (1)
IIEAT EXCHANGER TEST PROGRAM IN TEST TEST TEST SYSTEM HEAT EXCHANGER PROGRAM TYPE RESULTS COMMENTS Aux Feedpump Room N
NA NA NA S
Air Coolers E
R isophase Bus Duct Coolers N
NA NA NA V
I Condenser Air Removal N
NA NA NA C
Pump Seal Coolers E
Waterbox Priming N
NA NA NA Pump Seal Coolers W
Condensate Booster Pump N
NA NA NA A
Lube Oil Coolers T
E Instrument and Plant N
NA NA NA R
Air Compressor Coolers Turbine Plant Sample N
NA NA NA Coolers S
Y M/U Demin Vacuum N
NA NA NA S
Pump Cooler (U-1)
T E
N Compressor After N
NA NA NA 2
M Coolers (U-1)
Steam Generator Blowdown N
NA NA NA Recovery System Heat Exchanger
Page 4 of 7 ENCLOSURE (1)
IIEAT EXCHANGER TEST PROGILU1 IN TEST TEST TEST SYSTEM HEATEXCHANGER PROGRAM TYPE RESULTS COMMENTS C
II.B.
21 & 22 SAT No cleaning necessary.
O Heat Exchangers M
21 & 22 P
O HPSI Pump Seal &
Y IV.B.
Inspected 21 Based on test results of 12 pump and, N
Bearing Coolers Seal Cooler inspection results of 21 pump, inspecting 22 E
21,22, & 23 and 23 pumps, was not necessary. See N for details.
T LPSI Pump Seal &
N NA NA NA C
Bearing Coolers O
O Containment N
NA NA NA L
Penetration Coolers I
Main Feedwater G
Letdown RC Sample S/G Blowdown S
Y Reactor Vessel N
NA NA NA S
Support Coolers T
E S/G Lateral Support N
NA NA NA M
Coolers
Page 5 of 7 ENCLOSURE (1)
IIEAT EXCIIANGER TEST PROGRAM IN TEST TEST TEST SYSTEM HEAT EXCHANGER PROGRAM TYPE RESULE COMMENTS C
NA NA NA O
Waste Evaporators M
P Control Element Drive N
NA NA NA O
Mechanism Coolers N
E Reactor Coolant Pump N
NA NA NA N
Seal and Lube Oil Coolers T
Reactor Coolant Drain N
NA NA NA Tank Heat Exchangers C
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Letdown Heat Exchanger N
NA NA NA O
L Waste Gas Compressor N
NA NA NA I
Coolers N
G RCW Degasifier Vacuum N
NA NA NA Pump Coolers S
NSSS Sample Cooiers N
NA NA NA Y
RC Sample S'
SG Blowdown Sample T
MWS Sample E
M Post Accident Sample N
NA NA NA System Cooler
~ Page 6 of 7 ENCLOSURE (1) 11 EAT EXCllANGER TEST PROGRAM IN TEST TEST TEST SYSTEM HEAT EXCHANGER PROGRAM TYPE RESULE COMMENTS l
CCS Gas Analyzer Sample N
NA NA NA j
OOY Coolers 1
MOS PLT OI E MWS Heat Exchanger N
NA NA NA NNM EG N
T S/G Blowdown RAD Monitor N
NA NA NA Sample Cooler 1
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ENCLOSURE (1)
IIEAT EXCIIANGER TEST PROGRAM TEST TYPES 1.
Monitor and record cooling water flow and inlet and outlet temperatures for all affected heat exchangers during the modes of operation in which cooling water is flowing through the heat exchanger. For each measurement, verify that the cooling water temperatures and flows are within design limits for the conditions of the measurement. The test results from periodic testing should be trended to ensure that flow blockage or excessive fouling accumulation does not exist.
II.A.
Perform functional testing with the heat exchanger operating, if practical, at its design heat removal rate to verify its capabilities. Temperature and flow compensation should be made -
in the calculations to adjust the results of the design conditions. Trend the results, as explained above, to monitor degradation.
11.11.
Ifit is not practical to test the heat exchanger at the design heat removal rate, then trend test results for the heat exchanger efficiency or the overall heat transfer coefficient. Verify that heat removal would be adequate for the system operating with the most limiting combination of flow and temperature.
III.A Perform efficiency testing with the heat exchanger operating under the maximum heat load that can be obtained practically. Test results should be corrected for the off-design conditions. Design heat removal capacity should be verified. Results should be trended, as explained above, to identify any degraded equipment.
111.11 If it is not possible to test the heat exchanger to provide statistically significant results (for example,if error in the measurement exceeds the value of the parameter being measured),
then:
1.
Trend test results for both the air and water flow rates in the heat exchanger.
2.
Perform visual inspections, where possible, of both the air and water sides of the heat exchanger to ensure cleanliness of the heat exchanger.
IV.A.
If plant conditions allow testing at design heat removal conditions, verify that the heat exchanger performs its intended functions. Trend the test results, as explained above, to monitor degradation.
IV.II.
If testing at design conditions is not possible, then provide for extrapolation of test data to design conditions. The heat exchanger efficiency or the overall heat transfer coefficient of the heat exchanger should be determined whenever possible. Where possible, provide for periodic visual inspection of the heat exchanger. Visual inspection of a heat exchanger that is an integral part of a larger component can be performed during the regularly scheduled disassembly of the larger component. For example, a motor cooler can be visually inspected when the motor disassembly and inspection are scheduled.
ENCLOSURE (2)
JUSTIFICATION OF ALTERNATIVES TO TESTING FOR GENERIC LETTER 89-13 Described below is the justification of actions we have taken in lieu of the testing we committed to in Reference (b) for the following heat exchangers: Service Water (S'RW), Emergency Diesel Generator (EDG), High Pressure Safety Injection (HPSI) pumps, and Containment Air Cooling.
1.
SERVICE WATER HEAT EXCilANGERS Since extensive modifications were completed to the Saltwater System during the outage, we determined that performing baseline tests on the SRW heat exchangers would give us data that was not representative of system configuration following the outage. The modifications included replacing most concrete-lined pipe with rubber-lined pipe. Additionally, it included economizing pipe runs in the Saltwater System and, where possible, reducing the pipe diameter. We also made provisions for adding thermal wells to improve our ability to test the heat exchangers. The SRW heat exchangers will be tested the next time they are taken out-of. service for quarterly tube bulleting.
This is currently scheduled for fall 1993.
Reference (a) recommends and we agree that testing should be performed after corrective actions are taken to establish baseline data for future monitoring. Testing prior to such extensive modifications would have been an ineffective use of resources.
Similar to the discussion in Reference (c), there is no safety impact due to extending the heat exchanger test schedule. An extension to the schedule is acceptable based on the following-actions that we have taken:
1.
A design review of these heat exchangers has been conducted. We have confirmed from the review that their design is adequate to accomplish the required safety functions under worst-case accident conditions.
2.
The tube side of the heat exchangers has been cleaned by " bulleting" during the 1993 Unit 2 outage. Tube bulleting is currently performed quarterly.
3.
During maintenance, inspection and testing activities of the service water side (shell side) of the SRW System, no indications of fouling have been identified. The
. combination of these activities and chemistry control of the service water side of the SRW System provides us with reasonable assurance that it has not experienced any change in heat transfer capability since these activities.
Therefore, there is no safety impact from extending the heat exchanger test schedule to next quarMrly bulleting currently scheduled for fall 1993.
II.
EMERGENCY DIESEL GENERATOR COOLERS Based on the difficulties we experienced while attempting to obtain conclusive results from testing No.11 EDG during the 1992 Unit 1 Refueling outage, we decided that similar testing for the No. 21 EDG would also be inconclusive. For the reasons discussed below, we have concluded that inspection, in lieu of testing, will ensure that its heat exchangers are performing their heat removal function. In summary of the discussion in Reference (c), after our original tests to No.11 EDG failed to provide conclusive test results, we modified the EDG to improve the test. Subsequent tests gave us conclusive results for the jacket water cooler and the air coolant heat exchanger. However, we did not obtain conclusive test results for the No.11 lube oil cooler. We inspect EDG coolers at refueling intervals per vendor recommendations to verify their cleanliness. These inspections indicate there is no need to 1
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-r ENCLOSURE (2) ~
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JUSTIFICATION OF ALTERNATIVES TO TESTING
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FOR GENERIC LETTER 89-13 1
clean them. The lube oil is sampled and analyzed monthly. Reference (f) [ Question 6,-
page 19] states that when it is not practical to test a heat exchanger, an alternative such as j
inspection may be proposed. Additionally, during the performance of the engineering test for Generic Letter 89-13, we observed high heat exchanger bypass flow for the No.11 EDG lube oil cooler. This is a qualitative indication that its heat transfer capabilities are adequate to perform its intended function.
.l Therefore, we are confident that all'of the coolers for Nos.11,12 and 21 EDGs are:
performing their heat removal function. Our decision is consistent with Reference (f)
[ Question 8, page 20] which states that the initial heat exchanger test program may consist of performance testing of the most limiting heat exchangers combined with maintenance or cleaning of others. The family of heat exchangers is identical for each EDG, and their engine-side water is similar. For each individual EDG, the water chemistry of the jacket water cooler and air coolant heat exchanger is identical since these systems are cross--
'i connected. However, the water for No.11 EDG is the most limiting since historically we have had more difficulties maintaining its water chemistry control than the other two EDGs.
Therefore, there is no safety impact from substituting inspection for a heat exchanger test.
Since the SRW System is a closed system that is exhibiting no system-wide corrosion, we can now confirm the quality of our chemistry control program is sufficient to maintain adequate heat transfer capability. Future periodic testing of the closed system heat exchangers under
-l the scope of Generic Letter 89-13 is not necessary as long as the chemistry control program is adequately maintained [ Reference (a), page 5].
III.
IIIGli PRESSURE SAFETY IN.IECTION PUMP COOLERS l
The HPSI pumps include integral seal and bearing coolers that are mounted to the pump base and supplied by the pump vendor. There is continuous flow through the component cooling water side of the coolers. There is flow through the Reactor Coolant System (RCS) side of the bearing cooler only when the pump is operating. Otherwise, the RCS side is stagnant.
3 Based on the positive results of testing the No.12 HPSI pump cooler, we re-evaluated the need to inspect and/or test the Unit 2 HPSI pump coolers. We determined that the bearing coolers are not needed when fluid temperatures are less than 280 F.
Based on the containment analysis which uses the new containment air cooler duty curves, the maximum pump fluid temperature is below 264 F. Therefore, there is no need to test or inspect the bearing coolers. From our evaluation, we determined that the seal coolers must be capable of maintaining the seal injection temperature of approximately 170 F. Therefore, they should be inspected or tested.
The No. 21 pump seal cooler was inspected since we concluded that a detailed visual inspection will provide a better indication of the adequacy of our chemistry control program than a flow test. From the results of the No.12 HPSI pump flow test, we concluded that flow i
measurement can only provide an indication of gross macrofouling and virtually no indication of microfouling. We found that the tubes were clean with occasional small patches of rust.
There was a small amount of debris in the water, which we suspect was rust loosened by the inspection. No macrofouling was observed.
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ENCLOSURE (2)
JUSTIFICATION OF ALTERNATIVES TO TESTING FOR GENERIC LETTER 89-13 Since all Unit 1 and 2 HPSI pumps are of similar designs and of the No. 21 pump seal cooler was inspected and found clean, there is no need to inspect the Nos. 22 and 23 HPSI seal coolers. Additionally, since the component cooling water side of the HPSI bearing coolers is always operated cross-connected, the water chemistry in each Units' HPSI coolers is identical. A plant records review concluded there is no history of operating problems or maintenance orders for the Unit 2 pump coolers, The water chemistry program for the RCS side of the seal cooler is a documented, high quality closed loop water system. Finally, positive results from testing the Shutdown Cooling and Component Cooling Heat Exchangers is additional proof that the Component Cooling Water System is clean.
The combination of the results of testing and inspecting No.12 HPSI pump (Reference c),
the Unit 2 Shutdown Cooling and Co.nponent Cooling Heat Exchanger tests, the similarity of the Unit 1 and 2 HPSI pumps and the visualinspection results of the No.21 HPSI pump gives us confidence that the HPSI coolers have adequate heat transfer capability to perform t
their intended function. Our decision is consistent with Reference (f). Therefore, there is no safety impact from inspecting only one of these Unit 2 HPSI pump seal coolers (i.e., No. 21).
Since the Component Cooling Water System is a closed system that is exhibiting no system-wide corrosion, we can now confirm the quality of our chemistry control program is sufficient to maintain adequate heat transfer capability. Based on current test results, future periodic testing of these closed system heat exchangers under the scope of Generic Letter 89-13 is not necessary as long as the chemistry control program is adequately maintained [ Reference (a),
page 5].
IV.
CONTAINMENT AIR COOLERS There are four Containment Air Coolers in Unit 2. Coolers No. 21 and 22 are normally I
supplied by SRW Subsystem 21. Cooler Nos. 23 and 24 are normally supplied by SRW Subsystem 22. However, any cooler can be supplied from any subsystem.
Based on the difficulties associated with testing and obtaining statistically significant Type III.A test results for the Unit 1 Containment Air Coolers during the Spring 1992 Refueling Outage, we performed Type III.B air and water flow tests on the Unit 2 coolers similar to those we performed on Unit 1. The air flow tests were performed during the spring 1993 outage. The water flow tests were performed in 1991. To further ensure the adequacy of their heat removal capability, we also cleaned and inspected the air side of each cooler.
Based on the positive results of these actions, we have determined that future periodic testing of these closed system air coolers under the scope of Generic Letter 89-13 is not necessary as long as the chemistry control program is adequately maintained [ Reference (a),
page 5].
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