ML20237G032
| ML20237G032 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 08/18/1987 |
| From: | Andrews R OMAHA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| LIC-87-500, NUDOCS 8708210650 | |
| Download: ML20237G032 (6) | |
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Omaha Public Power District 1623 Harney Omaha. Nebraska 68102-2247 402/536-4000 August 18, 1987 LIC-87-500 U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555
Reference:
Doc'Ket No. 50-285 Gentlemen:
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SUBJECT:
Relief Request from Pump Flow Measurement Requirements of ASME Boiler and Pressure Vessel Code,Section XI Pursuant to 10 CFR 50.55a(g)(5)(iii), the Omaha Public Power District is for-warding for approval the attached relief request for the Fort Calhoun Station.
l Also enclosed as Attachment 2 are the proposed ISI Program Plan page revisions that would result from approval of this request.
The attachments specifically define our reasons for this request.
The $150.00 application fee required by 10 CFR 170 is also enclosed.
Sincerely, C
R. L. Andrews Division Manager Nuclear Production RLA/rh Attachments c:
LeBoeuf, Lamb, Leiby & MacRae l
1333 New Hampshire Avenue, N.W.
Washington, DC 20036 A. Bournia, NRC Project Manager P. H. Harrell, NRC Senior Resident Inspector g
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l Request for Relief from Compliance with the Signal Level Requirements of Sub-section IWP-4120 of the Winter 1980 Addenda to the ASME Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components.
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Subsection IWP-4120 states that reference signal levels for instruments re-quired for inservice test procedure must be greater than 1/3 of the full scale range of the instrument.
Following is a list of cases where Fort Calhoun's surveillance test procedures do not comply with this requirement.
1)
In Surveillance Test ST-FW-1 which deals with inservice testing of the auxiliary feedwater pumps FW-6 and FW-10, paragraph FW-6, F.2(2) states a reference value of "22-30 gpm" for pump flow using a flow indicator, FI-1368, that has a full scale range of 300 gpm.
t 2)
In the same test procedure as referenced in 1) above, paragraph FW-10, l
F.2(3) states a reference value of "85-115 gpm" for pump flow using a flow indicator, FI-1369, that has a full scale range of 300 gpm.
3)
In Surveillance Test ST-ISI-CVCS-3 whien deals with inservice testing of the charging pumps, paragraph CH-1A, F.2, Test Data 4, states a refer-j ence value of 37 gpm for pump flow using a flow indicator, FIA-236, that I
has a full scale range of 140 gpm.
4)
In the same test procedure as referenced in 3) above, paragraph CH-1B, 1
F.1, Test Data 4, states a reference value of 36 gpm for pump flow using the same flow indicator, FIA-236.
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5)
In the same test procedure as referenced in 3) above, paragraph CH-1C, F.1, Test Data 4, states a reference value of 37 gpm for pump flow using the same flow indication, FIA-236.
In the case of the AFW Pump Test (Items 1) and 2) above), the test is performed with a fixed resistance piping configuration that bypasses the pump discharge back to the Emergency Feedwater Storage Tank, FW-19, which also serves as a suc-tion source. The flow element is located in the pump suction line and is de-signed to measure full pump flow capacity.
The bypass piping is of relatively small diameter and will only allow a fraction of the full pump flow to pass.
Thus, the test flows are small compared to operational flow rates. Older edi-tions of ASME XI (e.g.,1974 which governed the original ISI Program Plan for j
Fort Calhoun Station) specifically stated that "In a fixed resistance system it is required to measure differential pressure or flow but not both."
In a fixed resistance system, measurement of either of these parameters is adequate to verify pump operability. The attempt to measure flow with the respective flow indicators at a level less than 1/3 of their full scale range results in a flow I
measurement that may be somewhat inaccurate, but this flow measurement still has value as a backup to the differential pressure measurement.
In light of the facts that pump degradation can be detected by the existing dif-ferential pressure measurements alone without flow measurements, that increas-ing the ratio of measured bypass flow to full scale instrument range would re-quire installing new flow devices or major modifications to the bypass piping l
and that testing in the bypass mode is necessary to prevent periodic injection l
of cold auxiliary feedwater into a hot steam generator, OPPD requests relief i
from the requirement of IWP-4120 as it relates to flow measurement in the sur-veillance testing of FW-6 and FW-10.
Pumps CH-1A, 8 and C (Items 3), 4) and 5) above) are in parallel and discharge into a common header.
Flow indicator FIA-236 measures flow in the common head-er.
FIA-236 has a full scale capacity designed to handle the total flow with
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the three pumps running.
The piping configuration used during the surveillance test is not a fixed resistance system, but rather remains the same as during operation.
Because of this configuration, associated pressures can vary. The charging pumps are positive displacement pumps and the surveillance test value of flow equates to approximately 26% of the full scale range of the instrument.
This reference flow rate is below the 1/3 requirement of IWP-4120, but is still l
within the calibration range of the instrument.
Additionally, the instrument is capable of providing flow readings that are consistent enough to contribute to the evaluation of pump operability.
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Because the reference flow level is below the requirement of IWP-4120 and be-l cause the flow reading recorded on past tests have been consistently within instrument calibration ranges and because increasing the ratio of measured test flow to full scale instrument range would require major instrumentation and piping modifications, OPPD requests relief from the requirements of IWP-4120 as 1
it relates to flow measurement in the surveillance testing of CH-1A, B and C.
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ATTACHMENT 2 l
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Exceptions:
IWP-3100 Flow measurement
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Basis: Original plant design did not include flow measurement for these pumps.
These pumps are in fixed resistance systems.
The inservice testing of differential pressure across these i
pumps under a minimum recirculation flow condition (and thus j
near shutoff head) is deemed adequate to allow determination of j
pump functionality and or degradation.
l IWP-3100 Inlet and differential pressure measurement I
Basis:
Inlet pressure for these tests will be determined by measuring the static head tank level.
s Charaina Pumos CH-1A, B, C Class 2 filD: CE-E-23866-210-120, Sheet 1 of 2 (E6, E4, E3) q i
Function: The charging pumps are provided to return the purification flow j
to the reactor coolant system during plant steady state operations.
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Subarticle Operating Mode j
Test Parameter Freauency Exceptions Reauired for Testina Inlet Pressure Quarterly 1, 2 or 3 Differential Pressure Quarterly 1, 2 or 3 Flow Rate Quarterly IWP-4120 1, 2 or 3 Vibration Amplitude Quarterly 1, 2 or 3 Lubricant Level and Pressure Quarterly 1, 2 or 3 Bearing Temperature Yearly 1, 2 or 3 i
Exceptions:
I IWP-4120 Flow measurement I
fla_111: System is designed for simultaneous flow of all three pumps. Therefore, reference flow is less than 1/3 of instrument full scale range.
Component Coolina Pumos AC-3A, B, C Class 3 P11D:
GHDR-11405-M-10 (D2, C2,B2) l Functhn:
The component cooling pumps supply cooling water to equipment in the containment and auxiliary building.
Operating Modes Subarticle Required for Test Parampfer Freauency Exceotions Testina j
Inlet Pressure IWP-3100 i'
Differential Pressure IWP-3100 Flow Rate IWP-3100 Vibration Amplitude Quarterly 1, 2, 3, 4 or 5 Lubricant Level of Pressure IWP-3100 l
Bearing Temperature Yearly 1, 2, 3, 4 or 5 j
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l Basis:
All bearings are inaccessible for temperature measurement. All are submerged in river water.
Discharge pressure vs. motor amperage l
Sasis:
To be performed in lieu of a differential pressure measurement. An acceptable motor amperage value will be determined over a di n arge pressure range of 26 through 40 psig.
Auxiliary Feedwater Pumns FW-6, FW-10 Class 3 l
P&ID:
GHDR-11405-M-253 Function: The auxiliary feedwater pumps provide water to the steam generators when normal condensate feedwater flow is unavailable.
Subarticle Required for Test Parameter Frecuency Exceotions Testina I
l Inlet Pressure Quarterly IWP-3100 1, 2 or 3 i
Differential Quarterly IWP-3100 1, 2 or 3 Pressure Flow Rate Quarterly IWP-4120 1, 2 or 3 1
Vibration Quarterly 1, 2 or 3 Amplitude i
Bearing Yearly 1, 2 or 3 Temperature Exceptions:
IWP-3100 Inlet pressure measurement Bas-is: System design does not permit direct measurement of
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inlet pressure.
Inlet pressure to be measured by observing j
Aux FW tank level or head.
Differential pressure measurement i
Basis:
Because of the inability to measure inlet pressure,
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direct differential pressure measurement is not possible, but it will be calculated by subtracting input from output pressure (in consistent units.)
IWP-4120 Flow measurement I
I fasis Due to small diameter bypass piping, reference flow
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is less than 1/3 of instrument's full scale range.
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