ML20059A775
| ML20059A775 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 12/22/1993 |
| From: | Richard Anderson NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9401030124 | |
| Download: ML20059A775 (19) | |
Text
49 Northern States Power Company 1
Prairie Island Nuclear Generating Plant 1717 Wakonade Dr. East Welch, Minnesota 55089 December 22, 1993 10 CFR Part 50 Section 50.55a(f) 1 U S Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555 PRAIRIE ISLAND NUCLEAR GENERATING PLANT Docket Nos. 50-282 License Nos. DPR-42 50-306 DPR-60 Submittal of Additional Requests for Relief for the 3rd 10-Year Inservice Testinz (IST) Pronram to the Reauirements of ASME Section XI We previously (June 16, 1993 and August 25, 1993) submitted for NRC Staff review our 3rd 10-Year ASME Code Section XI Inservice Testing (IST) Program.
The NRC completed its review and issued its Safety Evaluation Report (SER) on December 8, 1993 which approved the associated Requests for Relief with one exception.
In reviewing the SER and its attached Technical Evaluation Report we determined that we need additional relief. Attached are the additional Requests for Relief.
We will provide you with updates to the Inservice Testing Program Manual for information when significant revisions have been incorporated.(e.g., the addition of new components because of a significant modification to the plant).
Future Requests for Relief will be submitted if the need occurs.
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US NRC NORTHERN STATES POWER COMPANY December 22, 1993 Page 2 i
Please contact Jack Leveille (612-388-1121, Ext. 4662) if you have any questions related to this letter.
Roger O Anderson Director Licensing and Management Issues c: Regional Administrator - Region III, NRC Senior Resident Inspector, NRC NRR Proj ect Manager, NRC J E Silberg A S Jimenez (Hartford)
H Baron (State of Minnesota)
Attachments:
PI IST Unit 1, Request for Relief #11 (1 page)-
PI IST Unit 1, Request for Relief #12 (2 pages)
PI IST Unit 2, Request for Relief #12 '(:2 pages)
PI IST Unit 1, Request for Relief #13 (2 pages)
PI IST Unit 2, Request for Relief #13 (2'pages)
PI IST Unit 1, Request for Relief #14 (2 pages)
PI IST Unit 2, Request'for Relief #14 (2 pages)
PI IST Unit 1, Request for Relief #15 (2 pages)
PI IST Unit 1, Request for Relief #16-(2 pages) f 8
1
- 11. REQUEST FOR REllEF COMPONENT FUNCTION ASME ASME CODE VLV CLASS CAT 12, 22 Diesel Driven Cooling Water.
Remove heat from components that must function 3
Pump during accident conditions.
121 Motor Driven cooling Water Remove heat from components that must function 3
Pump during accident conditions.
CODE REQUIREMENT OMa 1988 Part 6 paragraph 4.6.2.2 specifies that, when determining differential pressure across a pump, a differential pressure gauge, a differential pressure transmitter that provides direct measurement of pressure difference or the difference between the pressure at a point in the intet pipe and the pressure at a point in the discharge pipe, may be used ALTERNATE TESTING Pump bay level will used to calculate the suction (inlet) pressure and allow the determination of oump differential pressure. The calculation of bay level Will be included in the surveillance procedure and supported by error analysis which shows the measurement of level and the calculational method yield an accuracy within d. 2%.
BASES FOR REQUESTING RELIEF The pumps have a submerged suction in the cooling water intake bay and inlet pressure indication is not available.
JUSTIFICATION The method is in accordance with a determination of differential pressure allowed by the Code. By including the calcu!ation in implementing procedures, the test can determine the differential pressure in a manner that is consistent and repeatable from test to test. This method will yield the information needed for monitoring the hydraulic condition of the applicable pumps without the need to install suction (inlet) pressure gauges which is not practical.
PI isT unit 1 3rd 10 Yest Program
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Rev.3 m-a-
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- 12. REQUEST FOR RELIEF COMPONENT FUNCTION ASME CODE CLASS 11,12 Component Cooling Pump Remove heat from components associated with removal 3
of reactor core decay heat under accident conditions.
CODE REQUIREMENT OMa - 1988 part 6 Section 5.2(b) requires that resistance of the system be varied until the flow rate equals the reference value prior to taking pressure readings.
ALTERNATE TESTING i
Pump flow, suction and discharge pressure are measured, then pump differential pressure plotted against flow to determine a
" point" on the pump curve. This point is then compared to Acceptance Criteria based on code allowabie required action ranges for Centrifugal pumps.
The following elements are performed in preparing pump curves:
3 1)
Pump curves are prepared or manufacturer's pump curves validated when the pumps are known to be operating acceptably.
2)
When measuring the reference points for plotting or validating the curve, instruments at least as accurate as the Code, OMa 1988 Part 6 Table 1, except as allowed by Request for Relief #2, will be used.
3)
Each curve will be constructed with a minimum of five points.
i 4)
The curve will be constructed using only those points beyond the " flat" portion (Iow flow rates) of the curves in a range which includes or is as close as practicable to design basis flow rates.
~
5)
Acceptance criteria for the pumps will be established such as to not conflict with the operability criteria for flow rate and differential pressure in the Technical Specifications or the USAR.
i l
l PI IST unit 1 3rd 10 Year Program Rev.3
- ~. _.
6)
If vibration levels vary significantly over the range of pump conditions a rnethod will be prepared to assign appropriate Vibration Acceptance Criteria for regions of the pump curve.
7)
When the reference curve may have been affected by repair, replacement or routine service, a new reference curve will be plotted or the previous curve revalidated by conducting an inservice test.
The curves that are currently used to establish acceptance criteria for these pumps will be changed to meet the above requirements.
BASES FOR REQUESTING RELIEF System design does not allow performance of hydraulic tests at specific reference points. Because of changing system loading conditions it is not practical to duplicate the exact reference point for each pump test. Some of the variable flows are the result of the cycling of flow control valves for system cooling demand. Examples of these variable loads are boric acid evaporator, spent -
fuel heat exchanger, letdown and excess letdown heat exchangers.
JUSTIFICATION Plotting pump curves for flow and differential pressure over the range of conditions expected during the systems' normal operation will allow evaluation of the pump in as-found system conditions. Implementing this process would allow confirmation of proper pump performance during in-situ testing. The proposed alternatives will give indication of any pump degradation.
I Pi isT unit 1 3rd 10 Year Program Rev.3
- 12. REQUEST FOR RELIEF r-COMPONENT FUNCTION ASME CODE CLASS 21,22 Component Cooling Pump Remove heat from components associated with removal 3
of reactor core decay heat under accident conditions.
CODE REQUIREMENT OMa - 1988 part 6 Section 5.2(b) requires that resistance of the system be varied until the flow rate equals the reference value prior to taking pressure readings.
ALTERNATE TESTING Pump flow, suction and discharge pressure are measured, then pump differential pressure plotted against flow to determine a
" point" on the pump curve. This point is then compared to Acceptance Criteria based on code allowable required action ranges for Centrifugal pumps.
The following elements are performed in preparing pump curves:
1)
Pump curves are prepared or manufacturer's pump curves validated when the pumps are known to be operating acceptably.
2)
When measuring the reference points for plotting or validating the curve, instruments at least as accurate as the Code, OMa 1988 Part 6 Table 1, except as allowed by Request for Relief #2, will be used.
3)
Each curve wili de constructed with a minimum of five points.
4)-
The curve will be constructed using only those points beyond the " flat" portion (Iow flow rates) of the curves in a range which includes or is as close as practicable to design basis flow rates.
5)
Acceptance criteria for the pumps will be established such as to not conflict with the operability criteria for flow rate and differential pressure in the Technical Specifications or the USAR.
Pt isT unit 2 l
3rd to Year Program
.Rev.3 m
6)
If vibration levels vary significantly over the range of pump conditions a method will be prepared to assign appropriate Vibration Acceptance Criteria for regions of the pump curve.
7)
When the reference curve may have been affected by repair, replacemei.t or routine service, a new reference curve will be plotted or the previous curve revalidated by conducting an inservice test.
The curves that are currently used to establish acceptance criteria for these pumps will be changed to meet the above requirements.-
BASES FOR REQUESTINd RELIEF System design does not allow performance of hydraulic tests at specific reference points. Because of changing system loading conditions it is not practical to duplicate the exact reference point for each pump test. Some of the variable flows are the result of the cycling of flow control valves for system cooling demand. Examples of these variable loads are boric acid evaporator, spent fuel heat exchanger, letdown and excess letdown heat exchangers.
JUSTIFICATION Plotting pump curves for flow and differential pressure over the range of conditions expected during the systems' normal operation will allow evaluation of the pump in as-found system conditions. Implementing this process would allow confirmation of proper pump performance during in-situ testing. The proposed alternatives will give indication of any pump degradation.
M IST unt 2 3rd 10 Year Program Rev.3 l
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- 13. REQUEST FOR RELIEF
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COMPONENT FUNCTION ASME CODE CLASS 11,12 Safety injection Pumps Deliver cooling water to the reactor core in the event of 2
a loss of coolant accident.
CODE REQUIREMENT OMa - 1988 Part 6 Section 4.6.5 specifies that, when measuring flow rate, use a rate or quantity meter installed in the pump test circuit.
ALTERNATE TESTING Each Safety injection pump, has a portion of its discharge flow which is unmetered. Specifically:
1.
11,12 Safety injection Pumps -These pumps have a minimum flow line which is un-instrumented and remains open during pump operation to provide flow through the pump should other flow paths be interrupted. This floev will not be metered during the full flow test at refueling outages. This flow is constant and is factored into the pump acceptance curves. Normal unmetered flow is approximately 10% of reference flow.
BASES FOR REQUESTING RELIEF installing flowmeters or flow orifices on bypass lines to meet code accuracies is not warranted due to the expense invnived with no commensurate benefit. Estimated costs required to install 2% accuracy flowmeters is $25,000 per pump.
1) 11,12 Safety injection Pumps -Isolation of the minimum flow line during full flow testing removes all backup pump cooling should discharge flow be interrupted. Flow through this minimum flow line will be constant durir g full flow.
testing. Long term increasing trends in the minimum flow line would conservatively be credited to pump degradation. Long term decreasing trends are unlikely due to the non corrosive property of the pipe ar,d the lack of tendency for the boric acid to form deposits at the concentrations used. The position of mini-flow valves are independently verified to be in the correct position and are tagged and wired open for pump protection.
PI IsT Unit 1 3rd 10 Year Program Rev.3
2)
Isolation of the minimum flow line during full flow testing removes all backup pump coofing should discharge flow. -
be interrupted.'
JUSTIFICATION The piping design and therefore system resistance of each bypass line will remain constant for each test. It can be shown that the pressure, flow and flow paths of the system during the pump testing, as controlled by the procedure, will assure negligible changes in the unmetered flow path. The pump metered flow and pressure readings taken during regular testing can be trended per code requirements and will give adequate indication should pump degradation occur. The installation of code accuracy metering instrumentation on these bypass lines would place an undue burden on the plant without a compensating increase in either quality or safety.
Pi isT Unit 1 3rd 10 Year Program Rev.3 n.-.
- 13. REQUEST FOR RELIEF COMPONENT FUNCTION ASME CODE CLASS 21, 22 Safety injection Pumps Deliver cooling water to the reactor core in the event of 2
a loss of coolant accident.
CODE REQUIREMENT OMa - 1988 Part 6 Section 4.6.5 specifies that, when measuring flow rate, use a rate or quantity meter installed in the pump test circuit.
ALTERNATE TESTING Each Safety injection pump, has a portion of its discharge flow which is unmetered. Specifically:
1.
21,22 Safety injection Pumps -Isolation of the minimum flow line during full flow testing removes all backup pump cooling should discharge flow be interrupted. These pumps have a minimum flow line which is un-instrumented and remains open during pump operation to provide flow through the pump should other flow paths be interrupted.
This flow will not be metered during the full flow test at refueling outages. This flow is constant and is factored into the pump acceptance curves. Normal unmetered flow is approximately 10% of reference flow.
BASES FOR REQUESTING RELIEF Installing flowmeters or flow orifices on bypass lines to meet code accura::ies is not warranted due to the expense involved with no commensurate benefit. Estimated costs required to install 2% accuracy flowmeters is $25,000 per pump.
1) 21,22 Safety injection Pumps - Flow through this minimum flow line will be constant during full flow testing. Long term increasing trends in the minimum flow line would conservatively be credited to pump degradation. Long term decreasing trends are unlikely due to the non corrosive property of the pipe and the lack of tendency for the boric acid to form deposits at the concentrations used. The position of mini-flow valves are independently verified to be in the correct position and are tagged and wired open for pump protection.
I PI isT unit 2 l
3rd to Year Program l
Rev.3
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2) isolation of the minimum flow line during full flow testing removes all backup pump cooling should discharge flow -
be interrupted.
JUSTIFICATION The piping design and therefore system resistance of each bypass line will remain constant for each test. It can be shown that the pressure, flow and flow paths of the system during the pump testing, as controlled by the procedure, will assure negligible changes in the unmetered flow path. The pump metered flow and pressure readings taken during regular testing can be trended per code requirements and will give adequate indication should pump degradation occur. The installation of code accuracy metering instrumentation on these bypass lines would place an undue burden on the plant without a compensating increase in either quality or safety.
1 Pi isT unit 2 3rd 10 Year Program.
Rev.3-
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- 14. REQUEST FOR RELIEF COMPONENT FUNCTION ASME CODE CLASS 11,12 Aux Feedwater Pumps Provide for removal of reactor core decay heat upon loss 3
-of normal feedwater.
CODE REQUIREMENT' OMa - 1988 Part 6 Section 4.6.5 specifies that, when measuring flow rate, use a rate or quantity meter installed in the pump test circuit.
ALTERNATE TESTING Each Aux Feedwater pump has a portion of its discharge flow which is unmetered. Specifically:
11,12 Aux Feedwater Pumps - These pumps have an unmetered bypass line which feeds a lube oil cooler and cooling must be provided during pump operation. This flow will not be metered during the full flow test at refueling outages. This bypass flow will be held constant during the test and is approximately 10-15% of reference flow.
BASES FOR REQt.lESTING RELIEF installing flowmeters or flow orifices on bypass lines to meet code accuracies is not warranted due to the expense involved with no commensurate benefit. Estimated costs required to install 2% accuracy flowmeters is $25,000 per pump.
11,12 Aux Feedwater Pumps -Isolation of the minimum flow line during full flow testing removes all backup pump cooling should discharge flow be interrupted. The unmetered flow is required for pump cooling and must be in service whenever the pump is in operation. Flow through this unmetered line will be constant during full flow testing. Long term increasing trends in the minimum flow line would conservatively be credited to pump degradation. Decreasing flow trends are unlikely since the condensate being pumped will not corrode or form deposits.
Pt isT unit 1 3rd lo Year Program Rev.3
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JUSTIFICATION The piping design and therefore system resistance of each bypass line will remain constant for each test. It can be shown that
. the pressure, flow and flow paths of the system during the pump testing, as controlled by the procedure, will assure negligible changes in the unmetered flow path. The pump metered flow and pressure readings taken during regular testing can be trended per code requirements and will give adequate indication should pump degradation occur. The installation of code accuracy metering instrumentation on these bypass lines would place an undue burden on the plant without a compensating increase in either quality or safety.
Pi isT Unit 1 3rd 10 Year Program Rev.3
.- ~
- 14. REQUEST FOR RELIEF COMPONENT FUNCTION ASME CODE CLASS y
d 21,22 Aux Feedwater Pumps Provide for removal of reactor core decay heat upon loss 3
of normal feedwater.
==
CODE REQUIREMENT OMa - 1988 Part 6 Section 4.6.5 specifies that, when measuring flow rate, use a rate or quantity meter installed in the pump test circuit.
ALTERNATE TESTING Each Aux Feedwater pump has a portion of its discharge flow which is unmetered. Specifically:
21, 22 Aux Feedwater Pumps - These pumps have an unmetered bypass line which feeds a lube oil cooler and cooling must be provided during pump operation. This flow will not be metered during the full flow test at refueling outages. This bypass flow will be held constant during the test and is approximately 10-15% of reference flow.
BASES FOR REQUESTING RELIEF Installing flowmeters or flow orifices on bypass lines to meet code accuracies is not warranted due to the expense involved with no commensurate benefit. Estimated costs required to install 2% accuracy flowmeters is $25,000 per pump.
21,22 Aux Feedwater Pumps -Isolation of the minimum flow line during full flow testing removes all backup pump cooling should discharge flow be interrupted. The unmetered flow is required for pump cooling and must be in service whenever the pump is in operation. Flow through this unmetered line will be constant during full flow testing. Long term increasing trends in the minimum flow line would conservatively be credited to pump degradation. Decreasing flow trends are unlikely since the condensate being pumped will not corrode or form deposits.
Pt tsT unit 2 3rd *o Yeer Program Rev.3
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JUSTIFICATION' The piping design and therefore system resi.
.cc of s <.: bypass line'will remain constant for each test, it can be shown that '-
the pressure, flow and flow paths of the system ounng the pump testing, as controlled by the procedure, will assure negligible changes in the unmetered flow paih. The pump metered flow and pressure readings taken during regular testing can be trended
- )er code requirements and will give adequate indication should pump degradation occur. The installation of code accuracy.
metering instrumentatiun on these bypass lines would place an undue burden on the plant without a compensating increase in-either quality or safety.
Pl !sT ' Unit 2 3rd lo Year Program Rev.3
- 15. REQUEST FOR RELIEF COMPONENT FUNCTION ASME CODE CLASS 12,22 Diesel Driven Cooling Water Remove heat from components that must function 3
Pumps during accident conditions.
CODE REQUIREMENT OMa - 1988 Part 6 Section 4.6.5 specifies that, when measuring flow rate, use a rate or quantity meter installed in the pump test circuit.
AU F ' 1 ATE TESTING Eech Cooling Water pump has a portion of its discharge flow which is unmetered. Specifically:
1)
The diesel driven pumps have an unmetered bypass line which feeds a jacket cooler and a gear oil cooler which must be available for engine cooling. This bypass flow will be held constant during the test and is estimated to be 1 % of reference flow.
2)
Additional small unmetered loads exist in the screenhouse, e.g., supply to chemical treatment and filtered water and affect the diesel cooling water pumps. Flow to
.e chemical treatment is estimated at 1 % and flow to filtered water at %% of reference flow. These flows are normally inservice and are held constant during the tests.
BASED FOR REQUESTING RELIEF installing flowmeters or flow orifices on bypass lines to meet code accuracies is not warranted due to the expense involved with no commensurate benefit. Estimated costs required to install 2% accuracy flowmeters is $25,000 per pump.
Isolation of flow to the diesel gear cooler and jacket cooler is not possible since this cooling is required during pump operation. The control valve that supplies tiv jacket cooler opens to the same position during each diesel test so PI IsT unit 1 3rd 10 Year Program Rev.3
. a
there is assurance that resistance will not change.
The remaining screenhouse unmetered flows affect both pumps in the same manner. The chemical treatment and
- filtered water flows are small and are continually in service.
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JUSTIFICATION The piping design and thcrt ors system rissistance of each bypass line will remain constant for each test. It can be shown that f
the pressure, flow and flow paths of the system during the pump testing, as controlled by the procedure, will assure negligible changes in the unmetered flow path. The pump metered flow and pressure readings taken during regular testing can be trended per code requirements and will give adequate indication should pump degradation occur. The installation of code accuracy metering instrumentation on these bypass lines would place an undue burden on the plant without a compensating increase in 2.
either quality or safety.
4 Pt isT unit 1 3rd 10 Year Program Rev.3
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- 16. REQUEST FOR REllEF COMPONENT FUNCTION
\\SME CODE CLASS 1?.1 Motor Driven Cooling Water Remove hebt from components that must function 3
, Pump during accident conditions.
CODE REQUIREMENT OMa - 1988 Part 6 Section 4.6.5 specifies that, when measuring flow rate, use a rate or quantity meter installed in the pump test circuit.
ALTERNATE TESTING 121 Cnoling Water purap has a portion of its discharge flow which is unmetered. Specifically:
Small unmetered loads exist in the screenhouse, e.g., supply to chemical treatment and filtered water and affect Coolir g Water pump. Flow to the chemical treatment is estimated at 1% and flow to filtered water at %% of reference flow. These flows are normally in service and 59 held constant during the tests.
BASES FOR REQUESTING RELIEF installing flowmeters or flow orifices on bypass lines to meet code accuracies is not warranted due to the expense involved with no commensurate benefit. Estimated costs required to install 2% accuracy flowmeters is $25.000 per pump.
The unmetered screenhouse flows are small and are continually in service.
JUSTIFICATION The piping design and therefore system resistance of each bypass line will remain constant for each test. It can be shown that the pressure, flow and flow paths of the system during the pump testing, as controlled by the procedure, will assure negligible changes in the unmetered flow path. The pump metered flow and pressure readings taken during regular _ testing can be trended
' Pt isT unit 1 3rd 10 Year Program Rev.3
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per code requirements and will give adequate indication should pump degradation occur; The' installation of code accuracy'-.*
metering instrumentation on these bypass lines would place an undue burden on the plant without a compensating increase in either quali_ty or safety.
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