ML20195B317
| ML20195B317 | |
| Person / Time | |
|---|---|
| Site: | Grand Gulf  |
| Issue date: | 11/09/1998 |
| From: | Eaton W ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| GNRO-98-00086, GNRO-98-86, NUDOCS 9811160093 | |
| Download: ML20195B317 (38) | |
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Entergy operations, Inc.
kt P O. Box 756 i
Port Gibson. MS 39150 l
3 Tel 601437 6409 FaxGot 437 2795 U"Csde Eaton -
November 9, 1998 gja
,sman i
e U.S. Nuclear Regulatory Commission j
j Mail Station P1-37 i
[
Washington, D.C. 20555 ~
Attention:
Document Control Desk
)
Subject:
_ Grand Gulf Nuclear Station Unit 1 Docket No. 50-416 License No. NPF-29 Revised Relief Requests i
j GNRO-98/00086 r
d' I
Gentlemen:
By letter dated November 26,1997 (GNRO-97/00112), Grand Gulf Nuclear Station (GGNS) submitted several relief requests related to the second interval of inservice Testing required i
by ASME Boiler and Pressure Vessel Code,Section XI,1989 edition (the Code). The submittal requested relief from certain requirements of the Code in accordance with 10 CFR 50.55a(f)(5) and (6). Several conference calls between the GGNS and the Nuclear i
Regulatory Commission (NRC) staffs (on 4-17-98, 5-1-98 and 6-18-98), resulted in several
. comments and suggestions to improve and/or clarify the requests. The attached relief 4
i requests incorporate these changes and supersede the previously submitted requests. We i '
would appreciate your timely review of the requests to support the implementation of the new interval, which began on December 1,1997.
1 Thank you in advance for your support and assistance in this matter. If you have any f
questions or need additional information, please contact Bill Brice at 601-437-6556.
Yours truly, h
WAE/WKH/WBB j
attachment:
cc:
(See Next Page)
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i 9811160093 981109 I POR ADOcn 05000416 p
PDR1 a
GNRO-98/00086 1
Page,2 of 2 cc:.
Ms. J. L. Dixon-Herrity, GGNS Senior Resident (w/a)
Mr. L. J. Smith (Wise Carter) (w/a)
Mr. N. S. Reynolds (wla)
Mr. H. L. Thomas (w/o)
Mr. E. W. Merschoff (w/a)
Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 400 Arlington,TX-76011 Mr. J. N. Donohew, Project Manager (w/2)
Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Mail Stop 13H3 Washington, D.C. 20555 s
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PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 5 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-B21-02 System:
B21 Feedwater System Component:
1B21-F010A 1821-F010B Category:
A, C
- Classj, 1
Function:
Open with flow for residual heat removal (RHR) system alternate shutdown cooling. Open with flow for feedwater leakage control (FWLC) operation.
Open with flow for RCIC operation (1821-F010B only). Close on reverse flow for containment isolation.
Impractical Test Requirements:
Check valves shall be exercised nominally every 3 months (OM Part 10, 4.3.2.1) except as provided by OM Part 10,4.3.2.2,4.3.2.3,4.3.2.4, and 4.3.2.5. During operation each check valve shall be exercised or examined in a manner that verifies obturator travel to the full-open, partially open, or closed position required to fulfill its function (OM Part 10, 4.3.2.2.(a)). As an alternative to the testing in OM Part 10, 4.3.2.4(a) or 4.3.2.4(b),
disassembly every refueling outage to verify operability of check valves may be used (OM Part 10,4.3,2.4(c)).
Basis for Relief:
Testing of check valves requires knowledge of the position of the disk. However, for these check valves the disk position cannot be ascertained during operation. These valves are-Y-pattern plug check valves, which close on reverse flow. There are no provisions in the system for inserting a large enough back flow against the valves to ensure that the disks close fully.
Check valves (1821-F032A and F0328) in the feedwater piping upstream of these valves prevent rapid depressurization of the upstream piping, which would be needed to build up a meaningful differential pressure across these valves.
Disassembly testing may be used to determine that a valve's disk will full-stroke exercise open or to verify closure capability, as allowed by OM Part 10, 4.3.2.4(c). Due to the scope of disassembly testing, the personnel hazards involved, foreign material exclusion (FME) concerns, planned maintenance activities and other operating restrictions, disassembly and inspection of both valves is not justified during each reactor refueling outage. Generic Letter 89-04 provides approval of Code deviations that are consistent with the NRC positions of the Generic Letter, Attachment 1.
This relief request meets the guidelines of Position 2 of the Generic Letter for.
implementation of a check valve sample disassembly and inspection program, as follows:
.v PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 6 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-821-02 (a)
Both valves are 24-inch Y-pattern plug check valves of the same design (same manufacturer, size, model number, and materials of construction).
(b)
Disassembly of such large valves is inherently hazardous to personnel safety and poses risks of damaging the valves or their component parts during the disassembly and reassembly. In addition, even with foreign material exclusion (FME) practices in effect, there is a finite probability of introducing foreign material into the feedwater piping and, eventually, into the reactor vessel through the open check valve bonnet.
(c)
Both valves are installed in feedwater piping, in the A and B feedwater line, at essentially the same place in the system and in the plant, and are in the same orientation. They experience essentially the same service and atmospheric conditions.
(d)
Both valves are located in the Drywell, which is inaccessible during power i
operation due to high radiation and is a high radiation area and a high contamination area during outages. The area they are in is difficult to access, is congested, and contains a number of obstacles to prevent efficiently disassembling and reassembling the valves.
Alternative Testing:
Where it is determined that it is burdensome to disassemble and inspect all applicable valves each refueling outage, the following Sample Disassembly and Inspection Plan for groups of identical valves in similar applications is employed. The requirements for grouping in accordance with this plan are explained below:
The Samp!e Disassembly and inspection Plan involves grouping valves of similar design, application and service conditions, and testing one valve in each group during each refueling outage. The grouping technique requires that for each valve in a group the following, as a minimum, be considered: Design, manufacturer, size, model number, service, orientation, and materials of construction. Valve group size is limited to four valves, maximum. These valves are a disassembly group of two valves.
One valve of this group will be disassembled and the internals inspected every refueling outage. When disassembly testing is performed, valves shall be tested as follows:
(a) At each disassembly it must be verified that the disassembled valve is capable of full-stroking and that the internals of the valve are structurally sound (no loose, corroded, worn, or failed parts).
(b) A different valve of each group is required to be disassembled, inspected, and manually full-stroke exercised at each successive refueling outage, until the entire group has been tested. At least one valve from each group is to be disassembled and
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PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 7 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-B21-02 examined at each refueling outage.
Once this is completed, the sequence of disassembly must be repeated. All valves in each group are to be disassembled and examined at least once every six years.
(c)
Before return to service, valves that were disassembled for examination or that
,aceived maintenance that could affect their performance, are to be exercised full-or part-stroke, with flow, if practicable. Both of these valves are exercised to the partially-open position quarterly and will be exercised prior to starting the plant after an outage during which one of the valves was disassembled for inspection.
i (d)
If the disassembled valve is not capable of being full-stroke exercised or there is i
binding or failure of valve internals, the remaining valves in that group must also be disassembled, inspected, and manually full-stroke exercised during the same outage.
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PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 8 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-E38-01 System:
E38 Feedwater Leakage Control (FWLC) System i
Component:
1E38-F002A 1E38-F002B 1E38-F002A 1E38-F002B Category:
C Class:
1 (1E38-F002A and F002B) 2 (1E38-F003A and F003B)
Function:
Open with flow to provide a post-LOCA containment isolation (leakage control) function by providing seal water to the feedwater lines. Close with reverse flow to provide overpressure protection in case of inadvertent FWLC system actuation during normal plant operation. Close with reverse flow to prevent cross flow from one feedwater line to the other if a differential pressure exists between the lines, f
Impractical Test Requirements:
Check valves shall be exercised nominally every 3 months (OM Part 10, 4.3.2.1) except as provided by OM Part 10,4.3.2.2,4.3.2.3,4.3.2.4, and 4.3.2.5. During operation each check valve shall be exercised or examined in a manner that verifies obturator travel to the full-open, partially open, or closed position required to fulfill its function (OM Part 10, 4.3.2.2.(a)). As an alternative to the testing in OM Part 10, 4.3.2.4(a) or 4.3.2.4(b),
disassembly every refueling outage to verify operability of check valves may be used (OM Part 10, 4.3.2.4(c)).
Basis for Relief:
Testing of check valves generally requires knowledge of the position of the disk or i
verification of the amount of flow passing through the valve. However, for these check valves the disk position or required flow values cannot be ascertained.
During power operation, these valves are held closed by feedwater pressure on the downstream side, making full-stroke or part-stroke open exercising impracticable. These valves are located in the Auxiliary Building Steam Tunnel, which is a high radiation area 1
and is inaccessible during power operation. Testing these valves in the closed direction i
requires personnel access and can be performed only during shutdown conditions. The i
valves are capable of being exercised closed and partially open during cold shutdowns, when the feedwater system is depressurized and the valve location is accessible.
7 Verifying that these valves full-stroke open cannot be accomplished without knowledge of the flow rate through the valves.
System design does not provide adequate instrumentation or test connections for measuring flow through the valves, even during cold shutdowns. There are no provisions in the system for measuring the flow rate through the FWLC lines. Ultrasonic flow measurement instrumentation has been used to verify that the check valves open to the partially-open position, but the instrumentation 1
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 9 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-E38-01 has not been determined to be capable of verifying fully-open function. In addition, these valves do not have any externalindications of the disk position, except that the disk can be forced onto its seat by closing the handwheel.
Disassembly testing may be used to determine that a valve's disk will full-stroke exercise open or to verify closure capability, as allowed by OM Part 10, 4.3.2.4(c). Due to the scope of disassembly testing, the personnel hazards involved, planned maintenance activities and system operating restrictions, all valves requiring disassembly and inspection may not be available for such testing during each reactor refueling outage.
Generic Letter 89-04 provides approval of Code deviations that are consistent with the NRC positions of the Generic Letter, Attachment 1.
This relief request meets the guidelines of Position 2 of the Generic Letter for implementation of a check valve sample disassembly and inspection program, as follows:
(a) All four valves are 1 1/2-inch Y-pattern stop-check valves of the same design (same manufacturer, size, model number, and materials of construction).
(b) Disassembly of even small valves poses risks of damaging the valves or their component parts during the disassembly and reassembly. In addition, even with foreign material exclusion (FME) practices in effect, there is a finite probability of introducing foreign material into the feedwater leakage control piping and, eventually, into the reactor vessel through the open check valve bonnet.
(c) All four valves are installed in FWLC lines leading to the Loop A and B feedwater piping, both upstream (1E38-F003A and F003B) and downstream (1E38-F002A and F002B) of the outboard check valve (1821-F032A and F032B), and are in the same orientation (upright in horizontal pipe runs). They experience essentially the same service and atmospheric conditions.
(d) All four valves are located in the Auxiliary Building Steam Tunnel, which is inaccessible during power operation due to high radiation and is a high radiation area and a contamination area during outages. In addition, the area is generally hot (above 100 F), even during cold shutdowns and refueling outages.
(e) Previous experience with disassembling and inspecting the internals of these four check valves during the first 10-year interval has not revealed any problems with any of the valves that would prevent any valve from performing its safety functions.
PROGRAM PLAN NO. GGNS-M-189.1 N
REVISION NO. 8 PAGE NO. 10 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-E38-01 Alternative Testing:
Relief is requested to disassemble one sample valve out of this sample group of four valves every refueling outage, instead of disassembling all four valves every refueling outage.
Where it is determined that it is burdensome to disassemble and inspect all applicable valves each refueling outage, the following Sample Disassembly and Inspection Plan for groups of identical valves in similar applications is employed. The requirements for grouping in accordance with this plan are explained below:
The Sample Disassembly and Inspection Plan involves grouping valves of similar design, application and service conditions, and testing one valve in each group during each refueling outage. The grouping technique requires that for each valve in a group the following, as a minimum, be considered: Design, manufacturer, size, model number, service, orientation, and materials of construction. Valve group size is limited to four valves, maximum. These valves are a disassembly group of four valves.
One valve of this group will be disassembled and the internals inspected every refueling outage. When disassembly testing is performed, valves shall be tested as follows:
(a) At each disassembly it must be verified that the disassembled valve is capable of full-stroking and that the internals of the valve are structurally sound (no loose, corroded, worn, or failed parts). If the disassembly is to verify the full-stroke capability of the valve, the disk is to be manually full-stroke exercised. Full-stroke motion of theobturator is to be reverified immediately prior to completing reassembly. Check valves (e.g., spring loaded lift check valves, or check valves with the obturator supported from the bonnet) that have their obturator disturbed before full stroke motion is verified, are to be examined to determine if a condition exists that could prevent full opening or reclosure of the obturator.
(b) A different valve of each group is required to be disassembled, inspected, and manually full-stroke exercised at each successive refueling outage, until the entire group has been tested. At least one valve from each group is to be disassembled and examined at each refueling outago.
Once this is completed, the sequence of disassembly must be repeated. All valves in each group are to be disassembled and examined at least once every six years.
(c)
Before return to service, valves that were disassembled for examination or that received maintenance that could affect their performance, are to be exercised full-or part-stroke, with flow, if practicable. All four of these valves are exercised to the partially-i open position and to the closed position in accordance with the cold shutdown testing frequency described in the Valve Program section of this program plan.
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t PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 11 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-E38-01 (d) If disassembly is the only means of verifying the valves full stroke, the check valve should be partially stroked quarterly or during cold shutdown, if practicable. All four of these valves are exercised to the partially-open position and to the closed position in accordance with the cold shutdown testing frequency described in the Valve Program section of this program plan.
(e) If the disassembled valve is not capable of being full-stroke exercised or there is binding or failure of valve internals, the remaining valves in that group must also be disassembled, inspected, and manually full-stroke exercised during the same outage.
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l PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 12 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-E38-01 System:
E51 Reactor Core isolation Cooling (RCIC) System Component:
1E51-F079 1E51-F081 Category:
-C Class:
2 Function:
Open to relieve vacuum to prevent siphoning suppression pool water into turbine exhaust line, which would result in turbine exhaust line transients.
Close to prevent RCIC turbine from exhausting directly to the containment air space.
Impractical Test Requirements:
Check valves shall be exercised nominally every 3 months (OM Part 10,4.3.2.1) except as provided by OM Part 10,4.3.2.2,4.3.2.3,4.3.2.4, and 4.3.2.5. During operation each check valve shall be exercised or examined in a manner that verifies obturator travel to the full-open or partially open position required to fulfill its function (OM Part 10, 4.3.2.2.(a)). As an alternative to the testing in OM Part 10, 4.3.2.4(a) or 4.3.2.4(b),
disassembly every refueling outage to verify operability of check valves may be used (OM Part 10, 4.3.2.4(c)).
Basis for Relief:
These valves are check valves (vacuum breakers) attached to the RCIC turbine exhaust line. Testing of check valves generally requires knowledge of the position of the disk or verification of the amount of flow passing through the valve. There are no installed flow measuring devices in the line and no flow path exists that can be used to pass flow through the valves for testing purposes. In addition, these valves do not have any externalindications of the disk position.
Disassembly testing may be used to determine that a valve's disk will full-stroke exercise open or to verify closure capability, as allowed by OM Part 10, 4.3.2.4(c). Due to the scope of disassembly testing, the personnel hazards involved, planned maintenance activities and system operating restrictions, all valves requiring disassembly and inspection may not be available for such testing during each reactor refueling outage.
Generic Letter 89-04 provides approval of Code deviations that are consistent with the NRC positions of the Generic Letter, Attachment 1.
This relief request meets the guidelines of Position 2 of the Generic Letter for implementation of a check valve sample disassembly and inspection program, as follows:
(a)
Both valves are 21/2-inch swing check valves of the same design (same manufacturer, size, model number, and materials of construction.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 13 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-E38-01 (b)
Disassembly of even small valves poses risks of damaging the valves or their component parts during the disassembly and reassembly. In addition, even with foreign material exclusion (FME) practices in effect, there is a finite probability of introducing foreign materialinto the RCIC piping through the open check valve bonnet.
(c)
Both valves are installed in the same vacuum relief line, in series approximately one foot apart, and are in the same orientation (upright in a horizontal run of pipe). They experience essentially the same service and atmospheric conditions.
(d) The valves are locatec' M the Auxiliary Building, in the overhead approximately 15 feet above the grating in the Low Pressure Core injection / Residual Heat Removal Loop A Pump room, in a high radiation area. A ladder or scaffolding is required for access to the valves.
(e)
Previous experience with disassembling and inspecting the internals of these two check valves during the first 10-year interval has not revealed any problems with either valve that would prevent either valve from performing its safety functions.
Alternative Testing:
Where it is determined that it is burdensome to disassemble and inspect both valves each refueling outage, the following Sample Disassembly and inspection Plan for groups of identical valves in similar applications is employed. The requirements for grouping in accordance with this plan are explained below:
The Sample Disassembly and Inspection Plan involves grouping valves of similar design, application and service conditions, and testing one valve in each group during each refueling outage. The grouping technique requires that for each valve in a group the following, as a minimum, be considered: Design, manufacturer, size, model number, service, orientation, and materials of construction. Valve group size is limited to four valves, maximum. Thes 3 valves are a disassembly group of two valves.
One valve of this group will be disassembled and the internals inspected every refueling outage. When disassembly testing is performed, valves shall be tested as follows:
(a) At each disassembly it must be verified that the disassembled valve is capable of full-stroking and that the internals of the valve are structurally sound (no loose, corroded, worn, or failed parts), if the disassembly is to verify the full-stroke capability of the valve, the disk is to be manually full-stroke exercised. Full-stroke motion of the obtumtor is to be reverified immediately prior to completing reassembly. Check valves (e.g., spring loaded lift check valves, or check valves with the obturator supported from the bonnet) that have their obturator disturbed before full stroke motion is verified, are to be examined to determine if a condition exists that could prevent full opening or reclosure of the obturator.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 14 OF 14 VALVE RELIEF REQUESTS VALVE RELIEF REQUEST NO.: VRR-E51-01 (b) A different valve of each group is required to be disassembled, inspected, and manually full-stroke exercised at each successive refueling outage, until the entire group has been tested. At least one valve from each group is to be disassembled and examined at each refueling outage.
Once this is completed, the sequence of disassembly must be repeated. Each of these two valves will be disassembled and examined at least every second refueling outage.
(c)
Before return to service, valves that were disassembled for examination or that i
received maintenance that could affect their performance, are to be exercised full-or part-stroke, with flow, if practicable. Both of these valves are exercised to the partially-open and closed positions quarterly and after maintenance, including disassembly for 1
inspection.
(d)
If disassembly is the only means of verifying the valves full stroke, the check valve should be partially stroked quarterly or during cold shutdown, if practicable. Both of these valves are exercised to the partially-open and closed positions quarterly and after maintenance, including disassembly for inspection.
(e)
If the disassembled valve is not capable of being full-stroke exercised or there is binding or failure of valve internals, the remaining valves in that group must also be disassembled, inspected, and manually full-stroke exercised during the same outage.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 1 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-E12-01 System:
E12 Residual Heat Removal System Component: E12C003A E12C003B E12C003C Type:
Centrifugal Class:
2 Function:
These jockey pumps operate continuously during normal operation to keep their respective main Low Pressure Core Injection (LPCI)/ Residual Heat Removal (RHR) pump discharge piping full of water.
impractical Test Requirements:
OMa-1988, Part 6, Para. 4.3: Reference values shall be determined from the results of preservice testing or from the results of the first inservice test. Reference values shall be at points of operation readily duplicated during subsequent tests. All subsequent test results shall be compared to these initial refe'ence values or to neyv reference values r
established in accordance with paras. 4.4 and 4.5.
Reference values shall only be established when the pump is known to be operating acceptably. If the particular parameter being measured or determined can be significantly influenced by other related conditions, then these conditions shall be analyzed.
OMa-1988, Part 6, Para. 4.6.1.2(a): The full-scale range of each analog instrument shall be not greater than three times the reference value.
OMa-1988, Part 6, Para. 4.6.1.3: The sensor location shall be.. appropriate for the parameter being measured.
OMa-1988, Part 6, Para. 5.2: An inservice test shall be conducted with the pump operating at specific test reference conditions. The test parameters shown in Table 2 shall be determined and recorded as directed in this paragraph.
OMa-1988, Part 6, Para. 5.2(b): The resistance of the system shall be varied until the flow rate equals the reference value. The pressure shall then be determined and compared to its reference value. Alternately, the flow rate can be varied until the pressure equals the reference value and the flow rate shall be determined and compared to the reference flow rate value.
OMa-1988, Part 6, Table 2: Flow Rate is a required test parameter for pumps.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 2 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-E12-01 Basis for Relief These jockey pumps are required to operate whenever their respective LPCl/RHR trains are in the operable condition. As such, the pumps perform continuous duty on a recirculation line and provide makeup as needed.
Pressure taps exist in the jockey pump suction and discharge piping where pump suction and discharge pressure can be measured for calculation of differential pressure, and throttle valves exist which can be used to set differential pressure equal to the pump's reference value. However, the pump differential-pressure information provided is of little use for analyzing the hydraulic condition of the jockey pump without being able to l
measure flow rate or set flow rate at a known reference value, as required by ASME/ ANSI OMa-1988 Part 6, Para. 5.2(b).
There are no practical means of measuring the flow rate of these jockey pumps. No flow rate meters, orifices or other measurement devices are installed in the system for measurement of jockey pump flow rate. The installed main LPCl/RHR process flow measurement instrumentation loops, which are discussed below, cannot be used for jockey pump flow measurement. Attempts have been made to use portable ultrasonic flow instruments to measure jockey pump flow rate, but the results have been too variable to be repeatable.
Flow orifices 1E12-FE-N014A, B, and C, which are installed in the system to measure flow rate of the main LPCl/RHR Pumps 1E12C002A, E, M C, each have a rated maximum flow rate of 10,000 gpm. Each flow instrument loop, ahich consists of the flow orifice, flow transmitter, flow indicator and signal processing electronics, has an overall loop accuracy of between one and two percent of the maximum measurable flow rate.
Even at the lower, more accurate, point, one percent accuracy is equivalent to 100 gpm, which is over 2-1/2 times the jockey pumps' rated flow rate of 40 gpm at 50psid (SAR Section 6.3.2.2.5). The flow orifices are installed in 18-inch NPS piping. Even if the typical operational jockey pump flow rate of 30 to 50 gpm registered on this flow instrumentation, it would not meet the requirements of ASME/ ANSI OMa-1988, Part 6, Para. 4.6.1.2 and 4.6.1.3, since the full-scale ranges of these analog instruments are more than 200 times the probable reference values for these jockey pumps. Under ideal conditions, the jockey pump flows would be just barely detectable at the lower end of the instrument scales, and accurate measurement would be masked by instrument noise and other conditions.
Additionally, the flow path for each of the jockey pumps in standby operation is through a minimum-flow return line with a flow-limiting orifice plate (1E12-RO-D002A, B or C) which is sized to hold flow late reasonably constant at about 40 gpm (SAR Figure 5.4-19),
while providing adequate margin in jockey pump capacity to make up for any leakage
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 I
PAGE NO. 3 OF 26 i
PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-E12-01 from the main LPCl/RHR pump discharge header. Flow rate through this orifice plate cannot be measured, as discussed above, since there are no installed measurement 1
points and portable flow rate instrumentation has not proven adequate. This flow rate also cannot be considered constant and repeatable enough to meet the requirements of ASME/ ANSI OMa-1988 Part 6, Para. 4.3, due to the potential for changes in the main l
LPCl/RHR discharge header leakage from test to test.
Additionally, jockey pump discharge header pressure is continuously monitored, and an anriunciator alarms in the Control Room if the discharge header pressure drops below a preset value, currently 40 psig for the Loop A and B jockey pumps and 28 psig for the Loop C jockey pump. Based on the pump's rated capacities (40 gpm at 50 psid, per SAR Section 6.3.2.2.5) and the required suppression pool level during power operation 1
(218 feet 4-1/12 inches and s 18 feet 9-3/4 inches per Tech Spec LCO 3.6.2.2), these low header pressure annunciators will alarm at approximately 70 percent of the Loop A and B jockey pumps' operating differential pressure, and at approximately 50 percent of the Loop C jockey pump's operating differential pressure.
Also, GGNS Technical Specification SR 3.5.1.1 requires verification every 31 days that the respective LPCl/RHR headers are filled with water by venting the piping at the high point vents. Such continuous monitoring and monthly venting will provide timely warning if a jockey pump has failed, or that system leakage has exceeded the capacity of the jockey pump.
In addition, these pumps are currently being monitored at least once a quarter under the GGNS Vibration Monitoring Program, which is currently not required by any Federal, state or industry requirements. Because rotating equipment faults that can be detected by vibration monitoring will show up any time the equipment is operating, returning these pumps to a fixed set of operating conditions is not necessary to detect such faults. The faults themselves, however, are affected by the equipment operating parameters. For example, if the equipment is heavily loaded, fault growth will typically be escalated.
These jockey pumps may be categorized as " smooth running," that is, they are typically running with very low vibration velocities. Each pump's flow rate is normally at or only slightly higher than the flow through the pump's minimum flow return piping. Any additional flow is typically only to make up for leakage from the main LPCl/RHR pump's discharge piping. Under these conditions, these pumps' reference values of vibration velocity are normally less than 0.05 inches per second (IPS).
Limits established in the GGNS Vibration Monitoring Program are not only based on vendor and industry data but also on changes in vibration levels and in the spectral content of the vibration signals. Unlike ASME/ ANSI OMa-1988, Part 6, Table 3a, which has fixed Alert and Required Action limits at 2.5 times and 6 times, respectively, of the reference values, the GGNS Vibration Monitoring Program analyzes changes in vibration t
l PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 4 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-E12-01 spectrum or spectral content over time, looks for trends in the changes, and attempts to determine the reasons for the changes. If changes are determined to be from an equipment problem, rather than changes in operating parameters, increased monitoring is established to determine the rate of the trend and equipment maintenance is scheduled to correct the problem before any vendor or industry recommendations or limits of ASME/ ANSI OMa-1988, Part 6 are expected to be exceeded.
Alternative Testing Hydraulic condition of the jockey pumps will be considered acceptable by continuing to monitor the pump discharge header pressures and verifying adequate header pressures, as indicated by the absence of low pressure alarms. Corrective action will be taken if header low pressure alarm sounds, indicating low header pressure.
Vibration will continue to be measured on these pumps as required by ASME/ ANSI OMa-1988, Part 6. Differential pressure will be set equal to its reference value prior to the measurements. (Reference values of vibration were taken with the jockey pumps in normal operation with header pressure alarm cleared and flow rate through the jockey pump minimum flow return orifice plate.) If a measured vibration velocity exceeds an i
Alert or Required Action limit of ASME/ ANSI OMa-1988, Part 6, Table 3a, the required actions of ASME/ ANSI OMa-1988, Part 6, Para. 6.1, " Acceptance Criteria," will be taken.
- ~ - -
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l PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 5 OF 26 PUMP RELIEF REQUESTS
~
PUMP RELIEF REQUEST NO.: PRR-E21-01 System:
E21 Low Pressure Core Spray System Component: E21C002 Type:
Centrifugal Class:
2 Function:
This jockey pump operates continuously during normal operation to keep the main Low Pressure Core Spray (LPCS) pump discharge piping full of water.
Impractical Test Requirements:
OMa-1988, Part 6, Para. 4.3: Reference values shall be determined from the results of preservice testing or from the results of the first inservice test. Reference values shall be at points of operation readily duplicated during subsequent tests. All subsequent test results shall be compared to these initial reference values or to new reference values established in accordance with paras. 4.4 and 4.5.
Reference values shall only be established when the pump is known to be operating acceptably, if the particu!ar parameter being measured or determined can be significantly influenced by other related conditions, then these conditions shall be analyzed.
OMa-1988, Part 6, Para. 4.6.1.2(a): The full-scale range of each analog instrument shall be not greater than three times the reference value.
OMa-1988, Part 6, Para. 4.6.1.3: The sensor location shall be.. appropriate for the parameter being measured.
OMa-1988, Part 6, Para. 5.2: An inservice test shall be conducted with the pump operating at specific test reference conditions. The test parameters shown in Table 2 shall be determined and recorded as directed in this paragraph.
OMa-1988, Part 6, Para. 5.2(b): The resistance of the system shall be varied until the flow rate equals the reference value. The pressure shail then be determined and compared to its reference value. Alternately, the flow rate can be varied until the pressure equals the reference value and the flow rate shall be determined and compared to the reference flow rate value.
OMa-1988, Part 6, Table 2: Flow Rate is a required test parameter for pumps.
i
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PROGRAM PLAN NO. GGNS-M-189.1 s
REVISION NO. 8 PAGE NO. 6 OF 26 4
1 i
PUMP RELIEF REQUESTS l
s PUMP REllEF REQUEST NO.: PRR-E21-01
\\
Basis for Relief I
This jockey pump is required to operate whenever the LPCS system is in the operable condition. As such, the pump performs continuous duty on a recirculation line and provides makeup as needed.
s Pressure taps exist in the jockey pump suction and discharge piping where pump suction l
and discharge pressure can be measured for calculation of differential pressure, and a i
throttle valve exists which can be used to set differential pressure equal to the pump's reference value. However, the pump differential-pressure information provided is of little
)
use for analyzing the hydraulic condition of the jockey pump without being able to measure flow rate or set flow rate at a known reference value, as required by 2
ASME/ ANSI OMa-1988 Part 6, Para. 5.2(b).
i-There are no r mtical means of miasuring the flow rate of this pump. No flow rate j
meters, orific or other measurement devices are installed in the system for measurement < jockey pump flow rate. The installed main process flow measurement j
instrumentatbn oop, which is discussed below, cannot be used for jockey pump flow j
measurement. Attempts have been made to use ultrasonic flow instruments to measure jockey pump flow rate, but the results have been too variable to be repeatable.
j.
j Flow orifice 1E21-FE-N002, which is installed in the system to measure flow rate of the main LPCS Pump 1E12C001, has a rated maximum flow rate of 10,000 gpm. The flow instrument loop, which consists of the flow orifice, flow transmitter, flow indicator and signal processing electronics, has an overall loop accuracy of between one and two percent of the maximum measurable flow rate. Even at the lower, more accurate, point, i
one percent accuracy is equivalent to 100 gpm, which is over 2-1/2 times the pump's rated flow rate of 40 gpm at 45 psid (SAR Section 6.3.2.2.5). The flow orifice is installed in 16-inch NPS piping. Even if the typical operational jockey pump flow rate of 30 to 50 i.
gpm registered on this flow instrumentation, it would not meet the requirements of f
ASME/ ANSI OMa-1988, Part 6, Para. 4.6.1.2 and 4.6.1.3, since the full-scale range of this analog instrument is more than 200 times the probable reference values for this jockey pump.
Under ideal conditions, the jockey pump flow would be just barely detectable at the lower end of the instrument scale, and accurate measurement would be masked by instrument noise and other conditions.
Additionally, the flow path for the jockey pump in standby operation is through a minimum-flow return line with a flow restricting orifice plate (1E21-RO-D003) which is sized to hold flow rate reasonably constant at about 40 gpm (SAR Figure 5.4-19), while providing adequate margin in jockey pump capacity to make up for any leakage from the main LPCS pump discharge header. Flow rate through this orifice plate cannot be measured, as discussed above, since there are no installed measurement points and portable fiow rate instrumentation has not proven adequate. This flow rate also cannot
l PROGRAM PLAN NO. GGNS-M-189.1 l,-
REVISION NO. 8 PAGE NO. 7 OF 26 l
PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-E21-01 be considered constant and repeatable enough to meet the requirements of ASME/ ANSI 1
OMa-1988 Part 6, Para. 4.3, due to the potential for changes in the main LPCS
{
discharge header leakage from test to test.
i Additionally, jockey pump discharge header pressure is continuously monitored, and an annunciator alarms in the Control Room if the main LPCS discharge header pressure drops below a preset value, currently 32 psig. Based on the jockey pump's rated l
capacity (40 gpm at 45 psid, per SAR Section 6.3.2.2.5) and the required euppression pool level during power operation (218 feet 4-1/12 inches and s 18 feet 9-3/4 inches per i
Tech Spec LCO3.6.2.2), this low hender pressure annunciator will alarm at approximately 60 percent of the joday pamp's operating differential pressure.
Also, GGNG Technical Specification SR 3.5.1.1 requires verification every 31 days that i
the main LPCS discharge header is filled with water by venting the piping at the high 2
point vent. Such continuous monitoring and monthly venting will provide timely warning if I
]
the jockey pump has failed, or that system leakage has exceeded the capacity of the j
jockey pump.
in addition, the pump is currently being monitored at least once a quarter under the j
GGNS Vibration Monitoring Program, which is currently not required by any Federal, state or industry requirements. Because rotating equipment faults that can be detected i
by vibration monitoring will show up any time the equipment is operating, returning the pump to a fixed set of operating conditions is not necessary to detect such faults. The faults themselves, however, are affected by the equipment operating parameters. For example, if the equipment is heavily loaded, fault growth will typ;cally be escalated.
This jockey pump may be categorized as " smooth running," that is, it is typically running with very low vibration velocities. The pump's flow rate is normally at or only slightly higher than the flow through the pump's minimum flow return piping. Any additional flow is typically only to make up for leakage from the main LPOS pump's discharge piping.
Under these conditions, the pump's reference values of vibration velocity are normally less than 0.05 inches per second (IPS).
Limits established in the GGNS Vibration Monitoring Program are not only based on vendor and industry data but also on changes in vibration levels and in the spectral content of the vibration signals. Unlike ASME/ ANSI OMa-1988, Part 6, Table 3a, which l
has fixed Alert and 'lequired Action limits at 2.5 times and 6 times, respectively, of the j
reference values, ti ^4GNS Vibration Monitoring Program analyzes changes in vibration spectrum or spectre ;ontent over time, looks for trends in the changes, and attempts to i
determine the reasons for the changes. If changes are determined to be from an equipment problem, rather than changes in operating parameters, increased monitoring is established to determine the rate of the trend and equipment maintenance is i
I i
1
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PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 8 OF 26 PUMP RELIEF REQUESTS PUMP REllEF REQUEST NO.: PRR-E21-01 scheduled to correct the problem before any vendor or industry recommendations or limits of ASME/ ANSI OMa-1988, Part 6 are expected to be exceeded.
Alternative Testing Hydraulic condition of the jockey pump will be considered acceptable by continuing to monitor the pump discharge header pressure and verifying adequate header pressures as indicated by the absence of low pressure alarm. Corrective action will be taken if header low pressure alarm sounds, indicating low header pressure.
Vibration will continue to be measured on this pump as required by ASME/ ANSI OMa-1988, Part 6. Differential pressure will be set equal to its reference value prior to the measurements. (Reference values of vibration were taken with the jockey pump in normal operation with header pressure alarm cleared and flow rate through the jockey pump minimum flow return orifice plate.) If a measured vibration velocity exceeds an Alcrt or Required Action limit of ASME/ ANSI OMa-1988, Part 6, Table 3a, the required actions of ASME/ ANSI OMa-1988, Part 6, Para. 6.1, " Acceptance Criteria," will be taken.
l
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 9 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-E22-01 System:
E22 High Pressure Core Sprey System Component: E22C003 Type:
Centrifugal Class:
2 Function; This jockey pump operates continuously during normal operation to keep the main High Pressure Core Spray (clPCS) pump discharge piping full of water.
Impractical Test Requirements OMa-1988, Part 6, Para. 4.3: Reference values shall be determined from the results of preservice testing or from the results of the first inservice test. Reference values shall be at points of operation readily duplicated during subsequent tests. All subsequent test results shall be compared to these initial reference values or to new reference values established in accordance with paras. 4.4 and 4.5.
Reference values shall only be established when the pump is known to be operating acceptably. If the particular parameter being measured or determined can be significantly influenced by other related conditions, then these conditions shall be analyzed.
OMa-1988, Part 6, Para. 4.6.1.2(a): The full-scale range of each analog instrument shall be not greater than three times the reference value.
OMa-1988, Part 6, Para. 4.6.1.3: The sensor location shall be... appropriate for the parameter being measured.
OMa-1988, Part 6, Para. 5.2: An inservice test shall be conducted with the pump operating at specific test reference conditions. The test parameters shown in Table 2 shall be determined and recorded as directed in this paragraph.
OMa-1988, Part 6, Para. 5,2(b): The resistance of the system shall be varied until the flow rate equals the reference value. The pressure shall then be determined and compared to its reference value. Alternately, the flow rate can be varied until the pressure equals the reference value and the flow rate shall be determined and compared to the reference flow rate value.
OMa-1988, Part 6, Table 2: Flow Rate is a required test parameter for pumps.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 I
PAGE NO. 10 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-E22-01 Basis for Relief l
This jockey pump is required to operate wnenever the HPCS system is in the operable condition. As such, the pump performs continuous duty on a recirculation line and j
provides makeup as needed.
Pressure taps exist in the jockey pump suction and discharge piping where pump suction and discharge pressure can be measured for calculation of differential pressure, and a throttle valve exists which can be used to set differential pressure equal to the pump's 4
i reference value. However, the pump differential-pressure information provided is of little 1
use for analyzing the hydraulic condition of the jockey pump without being able to measure flow rate or set flow rate at a known reference value, as required by ASME/ ANSI OMa-1988 Part 6, Para. 5.2(b).
j There are no practical means of measuring the flow rate of this pump. No flow rate meters, orifices or other measurement devices are installed in the system for measurement of jockey pump flow rate. The installed main process flow measurement instrumentation loop, which is discussed below, cannot be used for jockey pump flow 1
measurement. Attempts have been made to use ultrasonic flow instruments to measure jockey pump flow rate, but the results have been too variable to be repeatable.
I Flow orifice 1E22-FE-N007, which is installed in the system to measure flow rate of the main HPCS Pump 1E22C001, has a rated maximum flow rate of 10,000 gpm. The flow instrument loop, which consists of the flow orifice, flow transmitter, flow indicator and signal processing electronics, has an overall loop accuracy of between one and two percent of the maximum measurable flow rate. Even at the lower, more accurate, point, one percent accuracy is equivalent to 100 gpm, which is over 2-1/2 times the jockey pump's rated flow rate of 40 gpm at 45psid (SAR Section 6.3.2.2.5). The flow orifice is installed in 16-inch NPS piping. Even if the typical operational jockey pump flow rate of 30 to 50 gpm registered on this flow instrumentation, it would not meet the requirements 4
of ASME/ ANSI OMa-1988, Part 6, Para. 4.6.1.2 and 4.6.1.3, since the full-scale range of this analog instrument is more than 200 times the probable reference value for this jockey pump.
Under ideal conditions, the jockey pump flow would be just barely detectable at the lower end of the instrument scale, and accurate measurement would be masked by instrument noise and other conditions.
Additionally, the flow path for the jockey pump in standby operation is through a minimum-flow return line with a flow restricting orifice plate (1E22-RO-D003) which is sized to hold flow rate reasonably constant at about 40 gpm (SAR Figure 5.4-19), while providing adequate margin in jockey pump capacity to make up for any leakage from the main HPCS pump discharge header. Flow rate through this orifice plate cannot be measured, as discussed above, since there are no installed measurement points and portable flow rate instrumentation has not proven adequate. This flow rate also cannot
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 I
PAGE NO. 11 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-E22-01 be considered constant and repeatable enough to meet the requirements of ASME/ ANSI OMa-1988 Part 6, Para. 4.3, due to the potential for changes in the main HPCS discharge header leakage from test to test.
Additionally, jockey pump discharge header pressure is continuously monitored, and an annunciator alarms in the Control Room if the discharge header pressure drops below a i
preset value, currently 28 psig. Based on the pump's rated capacity (40 gpm at 45 psid, per SAR Section 6.3.2.2.5) and the required suppression pool level during power operation (218 feet 4-1/12 inches and s 18 feet 9-3/4 inches per Tech Spec LCO 3.6.2.2), this low header pressure annunciator will alarm at approximately 55 percent of the jockey pump's operating differential pressure.
Also, GGNS Technical Specification SR 3.5.1.1 requires verification every 31 days that j
the respective header is filled with water by venting the piping at the high point vents.
Such continuous monitoring and monthly venting will provide timely warning if the jockey pump has failed, or that system leakage has exceeded the capacity of the jockey pump.
In addition, the jockey pump is currently being monitored at least once a quarter under the GGNS Vibration Monitoring Program, which is currently not required by any Federal, state or industry requirements. Because rotating equipment faults that can be detected i
by vibration monitoring will show up any time the equipment is operating, returning the pump to a fixed set of operating conditions is not necessary to detect such faults. The faults themselves, however, are affected by the equipment operating parameters. For example, if the equipment is heavily loaded, fault growth will typically be escalated.
This jockey pump may be categorized as " smooth running," that is, it is typically running with very low vibration velocities. The pump's flow rate is normally at or only slightly higher than the flow through the pump's minimum flow return piping. Any additional flow is typically only to make up for leakage from the main HPCS pump's discharge piping.
Under these conditions, the pump's reference values of vibration velocity are normally less than 0.05 inches per second (IPS).
Limits established in the GGNS Vibration Monitoring Program are not only based on j
vendor and industry data but also on changes in vibration levels and in the spectral content of the vibration signals. Unlike ASME/ ANSI OMa-1988, Part 6, Table 3a, which has fixed Alert and Required Action limits at 2.5 times and 6 times, respectively, of the reference values, the GGNS Vibration Monitoring Program analyzes changes in vibration spectrum or spectral content over time, looks for trends in the changes, and attempts to determine the reasons for the changes. If changes are determined to be from an equipment problem, rather than changes in operating parameters, increased monitoring is established to determine the rate of the trend and equipment maintenance is scheduled to correct the problem before any vendor or industry recommendations or limits of ASME/ ANSI OMa-1988, Part 6 are expected to be exceeded.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8
?
PAGE NO. 12 OF 26 I
PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-E22-01 Alternative Testing Hydraulic condition of the jockey pump will be considered acceptable by continuing to monitor the pump discharge header pressures and verifying adequate header pressures, as indicated by the absence of low pressure alarms. Corrective action will be taken if l
header low pressure alarm sounds, indicating low header pressure.
Vibration will continue to be measured on this pump as required by ASME/ ANSI OMa-1988, Part 6. Differential pressure will be set equal to its reference value prior to the l
measurements. (Reference values of vibration were taken with the jockey pump in i
normal operation with header pressure alarm cleared and flow rate through the jockey pump minimum flow return orifice plate.) If a measured vibration velocity exceeds an i
Alert or Required Action limit of ASME/ ANSI OMa-1988, Part 6, Table 3a, the required actions of ASME/ ANSI OMa-1988, Part 6, Para. 6.1, " Acceptance Criteria," will be taken.
t J
r
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO.13 OF 26 i
PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P75-01 i
System:
P75 Standby Diesel Generator System Component: 1P75C002A 1P75C002B 1
Type:
Centrifugal
- Class:
3 Function:
Transfer fuel oil from the storage tank to the day tank for the standby diese!
generators.
l Impractical Test Requirements:
OMa-1988, Part 6, Para. 5.2: An inservice test shall be conducted with the pump operating at specified test reference conditions. The test parameters shown in Table 2 i
shall be determined and recorded as directed in this paragraph.
OMa-1988, Part 6, Para. 5.2(b): The resistance of the system shall be varied until the flow r&te equals the reference value. The pressure shall then be determined and i
compared to its reference value. Alternately, the flow rate can be varied until the pressure equals the reference value and the flow rate shall be determined and compared to the reference flow rate value.
OMa-1988, Part 6, Table 2: Differential Pressure is a required test parameter for centrifugal pumps.
Basis for Relief l
The physical locations of the Standby Diesel Generator (SDG) fuel oil transfer pumps are at the bottoms of the respective SDG fuel oil storage tanks, which are buried in the ground outside the diesel generator bays. The pump design specifies each pump to be submerged in the fuel oil with the 3/4-inch discharge piping rising from the pump, through the fuel oil, and out the top of the tank approximately 13 feet above the pump discharge.
Approximately 1 foot above the tank, the 3/4-inch piping widens to 2-inch diameter pipe.
A 2-inch check valve near the expansion fitting prevents fuel oil in the transfer piping from draining back into the storage tank. The 2-inch piping rises approximately 15 to 16 i
inches, elbows twice during the next 29-inch run, and then flanges 20 inches later prior to entering the ground. Since good engineering design requires a minimum of 5 pipe diameters both upstream and downstream for source pressure measurement, the only adequate location for a pressure instrument tap within this exposed piping between the top of the storage tank and the ground entry point is the 29 inch run. However, as the following justification will identify, locating a pressure tap in this exposed pipe run will not
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO.14 OF 26 1
PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P75-01 provide a significant increase in the usefulness of a discharge pressure measurement in this location.
The 2 inch piping then runs underground to the respective SDG rooms, and rises above ground level enroute to the day tank. Shortly after the 2-inch piping exits the ground in the respective SDG room, but prior to the SDG fuel oil strainer, is the pressure instrument tap used to measure the transfer pump discharge pressure. This pressure instrument tap is the current location for measurement of the pump discharge pressure, and is located approximately 12 feet above the 3/4-to-2 inch expansion fitting (24 feet 4
above the actual pump discharge), and approximately 10 feet below the highest piping elevation in the run to the day tank.
4 As noted above, the 3/4-inch diameter discharge piping run and elevation rise are both approximately 13 feet. The 2-inch diameter fuel oil transfer piping run is approximately 295 feet (SDG "B") and 360 feet (SDG "A"), with a total rise of 22 feet before entering the 5
top of the respective SDG day tank.
For both trains of the SDG fuel oil transfer piping, the only isolation valve is a manual globe valve which is located in the highest elevation run of the 2-inch piping shortly j
upstream of where the pipe enters the day tank.
Between August 1994 and July 1997, 15 inservice tests were performed and documented for trending purposes for the 1P75C002A pump. [For brevity, only test data from the "A" pump is given. The "B" pump exhibits similar results.) For these 15 tests, the pressure readings at the current instrument location ranged from 3.96 to 5.51 psig, which obviously does not reflect the true discharge pressure of the pump. The suction pressure, which is calculated utilizing the level of the storage tank, has ranged from 3.43 to 3.67 psig during these tests. The calculated differential pressure utilizing only the discharge pressure instrument and suction pressure has ranged from 0.34 to 2.04 psid.
This calculated differential pressure is clearly not representative of the actual pump differential pressure.
Based on a system resistance calculation, these pumps experience approximately 68%
to 70% of the total head loss in the 3/4-inch piping. Thus, only approximately 30% of the actual pump discharge pressure is measurable at the 3/4-to-2-inch reducer. From the reducer to the pressure instrument tap location, another 5 psi drop is experienced due to the elevation difference alone.
Although the actual pressure readings documented during the test period analyzed have been in the range expected, the information has provided very little value as a pump degradation tool. The average measured discharge pressure over the analyzed tests is i
approximately 5.30 psig, with the average suction pressure being approximately 3.57 psig, thus the average differential pressure has been around 1.73 psid. As an attempt to
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PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO.15 OF 26 PUMP RELIEF REQUESTS 4
PUMP RELIEF REQUEST NO.: PRR-P75-01 1
i make the differential pressure measurement a more practical pump performance indicator, a correction factor was calculated based on the respective SDG fuel oil system resistances. However, testing experience has indicated that even the use of a correction factor has not increased the usefulness of the differential-pressure determinations for these pumps, as the following discussion will establish.
The system resistance is based on the flow rate, and therefore the correction factor utilized would need to be based on the system flow rate during the test. This would necessitate setting the flow rate at a fixed value (32.75 gpm being the current reference value), and determining the pump differential pressure, OR setting the differential pressure and determining the flow rate. Both of these test methods are considered to be impractical for the following reasons:
(1)
Flow rate is determined by measuring the day tank level change from the low-level alarm to the pump shutoff level, and dividing the change by the pump run time. As such, instantaneous flow measurement is not available to allow simple adjustment to establish a fixed flow rate. There are no installed flow meters or taps for measuring flow rate directly. Ultrasonic flow measurement attempts using a portable instrument hsve proven to be inconsistent when compared to the level change method. The current j
method for determination of flow rate meets the loop accuracy requirements mandated per Table 1 of ASME/ ANSI OMa-1988 Part 6. Modification to install a flow meter solely for the purpose of providing instantaneous flow indication to a' low establishment of a fixed flow rate is not necessary for evaluating the hydraulic condition of these pumps for i
the reasons specified in this relief request.
(2)
Differential pressure is determined by a calculation of the measured discharge pressure plus the correction factor minus the suction pressure. The suction pressure is from a real-time calculation based on the storage tai k level measurement during the i
pump run. To ensure full loop accuracy, a Barton tube gauge (0-200 inches of water) is utilized to measure the discharge pressure, and thus requires a real-time calculation to convert inches of water to psi. Thus, three calculations would be required for each valve adjustment to establish a differential pressure. To utilize differential pressure as the fixed parameter, each system adjustment to set the differential pressure to the reference value would necessitate the performance of these three calculations. Each performance of these calculations adds time to the pump run duration and unnecessarily increases the potential for calculational error, (3)
The pump run is typically 8-10 minutes which, as noted above, will not allow for a i
fixed parameter adjustment during the pump run. Thus, the day tank would need to be j
drained to the low level for another pump run once the differential pressure is correctly l
adjusted. The breaker for the pump must be opened in order to drain the day tank to the low level alarm. bonecessary cycling of component breakers solely for the purpose of performance testing is not desirable.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO.16 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P75-01 (4)
The globe valve is the only available means of adjusting the system resistance to set either flow rate or differential pressure equal to its reference value; however, adjusting the globe valve will change the system resistance upon which the differential pressure correction factor is based. The corresponding resistance factor for the position of the globe valve would need to be determined to re-perform the system resistance calculation, and could necessitate the performance of the system resistance calculation during each pump test depending upon the sensitivity of the valve's resistance factor versus valve position. In either case, valve adjustment would add additional uncertainty to the correction factor applied to the differential pressure measurements, which would further reduce the usefulness of the differential pressure as a pump performance parameter.
(5)
Evaluation of the inservice t=
results for these pumps has shown that differential pressure measurement is r widing any substantial benefit as a diagnostic tool for pump hydraulic performance.
The current differentS! pressure reference values for these pumps are 28.11 ("A") and 28.29 ("B") psid. These reference values are based on correction factors from the system resistances at an average flow rate of 33.0 gpm. Even though a different reference flow rate (32.75 gpm) has been established since the original differential pressure reference values were determined, there has been absolutely no change in the average differential pressure results for the tests at the new flow reference value. If a new reference value is established based on a correction factor at 32.75 gpm, the same test results would be averaged around the new correction factor because of the very little variation between the measured suction and discharge pressures.
- However, establishing new correction factors or reference values would provide no additional benefit as noted below.
1 Per Table 3b of ASME/ ANSI OMa-1988, Part 6, the acceptance criteria can deviate from the reference value by as much as 10% (2.8 psi) before corrective action is necessary.
In order to achieve a 2.8 psi drop in differential pressure, the measured discharge pressure would have to drop to approximately 1.2 to 2.4 psig since suction pressure remains fairly constant. The pressure drop due solely to the elevation difference between the pressure instrument location and the maximum elevation exprienced enroute to the day tank is approximately 4 psi. As such, flow would have to drop dramatically, and even cease, before the differential pressure ever came close to the lower required action value. Therefore, it has become clear that the only parameter which is currently providing any true representation of the pump hydraulic condition is the flow rate.
To make the measurement of the pump differential pressure a useful parameter for pump pcrformance evaluation, it would be necessary to perform a modification to install
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PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO.17 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P75-01 the pump discharge pressure gage closer to the pump discharge. Such a modification is 4
considered to represent an unusual hardship without a compensating increase in the level of quality and safety for the following reasons:
(a)
Any modWion would require removal of the fuel oil transfer pump from the associated fuel o orage tank to make the necessary modification.
(b)
A direci aensing instrument at the pump's discharge flange or the beginning of i
the discharge pipe would be submerged in the fuel oil with the pump.
For this application, a pressure transducer would be required in lieu of a pressure gage. Such an 4
arrangement would necessitate the removal of the pump assembly from the storage tank every time the pressure transducer required calibration.
(c)
If a pressure gage option were used with the tap location at the discharge of the pump and the transducer located elsewhere, the least impact would be caused by routing the gage sensing line along with the fuel discharge piping. However, this option would require an additional modification to the existing discharge flange arrangement at the top of the storage tank to allow the sensing line to penetrate the tank (any other penetration location would necessitate an entry into the tank to disconnect the sensing line whenever the pump is required to be pulled for planned or corrective maintenance.)
Once this modification was performed, a correction factor will still need to be calculated to account for the elevation difference between the gage and the pump.
(d)
The current test configuration allows the fuel oil transfer system to be treated as a fixed-resistance system due to the negligible head loss between the current discharge measurement location and the day tank. If a modification were performed to allow for more practical discharge pressure measurement, the system may no longer qualify as a fixed-resistance system depending upon the modification performed. If such were the case, resistance adjustment would necessitate at least two pump runs per quarter as discussed above. The option does exist to keep the drain open on the day tank while the adjustment is made, and then the drain would be shut for the level measurement. This option, however, could significantly reduce the accuracy of the flow rate measurement due to the shorter pump run time and due to the need to measure the initial tank level while the pump is actually filling the tank, instead of during a stable, no-flow condition.
(e)
Safety-related maintenance activities, such as the removal of this pump for any reason, are expensive undertakings and involve risks associated with the disassembly of any piping system.
Performance of a modification requiring such activities will significantly increase the cost burden.
(f)
Working with fuel oil systems involves additional personnel and equipment safety hazards, which should be minimized whenever possible.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO.18 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P75-01 (g)
If the transducer option were installed, removal and reinstallation of the pump assembly would be necessary for calibration purposes. This would require additional testing to be performed on the system to ensure that the maintenance activity did not impact the hydraulic performance capability of the fuel oil transfer system. Such testing would require verification that the reference values of the pump hydraulic parameters were not r.ffected. if a transducer ar angement were used, then revalidation of the reference values would be required at the same periodicity as the instrument calibration.
(h)
Finally, diesel-generator operability and availability could be adversely affected by an installation of any modification that would require multiple test runs of the fuel oil transfer pump or frequent storage tank entries for calibration purposes should such instrumentation be installed.
Alternative Testing As noted in the preceding discussion, the existing means of measuring pump differential pressure does not provide any useful information regarding the pump hydraulic condition that would not be readily apparent by a corresponding decrease in pump flow. For the fuel oil transfer system pumps, the measurement of flow rate alone, with the following additional requirements, will provide an acceptable level of quality and safety while having minimal negative impact on diesel-generator operability and availability.
Before starting the pumps, adequate storage tank level will be ensured for pump net positive suction head (NPSH) requirements. The systems will be left in their normal alignment with no valves throttled. The day tanks will be drained to a low level and then refilled using the associated fuel oil transfer pump. An average flow rate will be calculated and compared to its reference value in order to determine if any pump degradation is occurring. A lower " alert value" (not presently required per Table 3b of OMa-1988, Part 6 for centrifugal pumps) of 93% of the reference flow rate value will be established for each of the pumps. If the measured flow rate falls below this " alert value," then the analyses and evaluation actions required by Section 6 of OMa-1988, Part 6 for pump performance in the alert range will be perfomied.
Although not specifically provided as alternative testing requirements for these pumps, the following summarizes alternative means and supplies for providing fuel oil to the SDGs in the event that a fuel oil transfer pump is inoperable. Some of these supplies are more fully described in SAR 9.5.4.
The SDG day tanks are equipped with low level switches that alarm in the Control Room.
Various portable electric, gasoline, and diesel-driven punips are available on-site that could be used in an emergency to refill the day tanks by pumping from the storage tanks.
Each SDG installation includes provisions for manually refilling the day tanks from outside the Diesel-Generator Building.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO.19 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P75-01 Entergy Corp. maintains supplies of diesel fuel at power plants in Vicksburg, MS (approxine ly 25 miles from Grand Gulf Nuclear Station, GGNS) and inNatchez, MS (approximately 40 miles from GGNS). GGNS also maintains a contract with a fuel oil supply company in the surrounding area for resupply of SDG fuel oil as part of emergency planning, and the trucks from this company have pumps which could also resupply the SDG day tanks.
Finally, a fuel oil truck is maintained on-site at GGNS which is normally used for refueling portable diesel engines around the site (e.g., portable pumps, generators, compressors, etc.) The truck has 1,100 gal capacity and can be refilled from an on-site storage tank.
The truck could be used in an emergency to refill the fuel oil day tank, even though neither the quantity nor the quality (purity and chemical analysis) of the fuel oil in either the truck or the storage tank is controlled for emergency purposes.
4 4
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 l
PAGE NO. 20 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P81-01 System:
P81 High Pressure Core Spray (HPCS) Diesel Generator System Component: IP81C002 Type:
Centrifugal Class:
3 Function:
Transfer fuel oil from the storage tank to the day tank for the HPCS diesel generator.
Impractical Test Requirements:
OMa-1988, Part 6, Para. 5.2: An inservice test shall be conducted with the pump operating at specified test reference conditions. The test parameters shown in Table 2 shall be determined and recorded as directed in this paragraph.
OMa-1988, Part 6, Para. 5.2(b): The resistance of the system shall be varied until the flow rate equals the reference value. The pressure shall then be determined and compared to its reference value. Alternately, the flow rate can be varied until the pressure equals the reference value and the flow rate shall be determined and compared to the reference flow rate value.
OMa-1988, Part 6, Table 2: Differential Pressure is a required test parameter for centrifugal pumps.
Basis for Relief The physicallocation of the High Pressure Core Spray Diesel Generator (HPCS DG) fuel oil transfer pump is at the bottom of the HPCS DG fuel oil storage tank, which is buried in the ground outside the diesel generator bay. The pump design specifies the pump to be submerged in the fuel oil with the 3/4-inch discharge piping rising from the pump, through the fuel oil, and out the top of the tank approximately 11 feet above the pump discharge.
Less than 1 foot above the tank, the 3/4-inch piping widens to 2-inch diameter pipe. A 2-
' inch check valve near the expansion fitting prevents fuel oil in the transfer piping from draining back into the storage tank. The 2-inch piping rises approximately 4 inches, elbows twice during the next 14-inch run, and then flanges 9 inches later prior to entering the ground. Since good engineering design requires a minimum of 5 pipe diameters both upstream and downstream for source pressure measurement, there is no adequate location for a pressure instrument tap within this exposed piping between the top of the storage tank and the g.Jund entry point.
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO 8 PAGE NO. 21 OF 26 7
I PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P81-01 The 2 inch piping then runs underground to the HPCS DG room, and rises above ground level enroute to the day tank. Shortly after the 2-inch piping exits the ground in the HPCS DG room, but prior to the DG fuel oil strainer, is the pressure instrument tap used to measure the transfer pump discharge pressure. This pressure instrument tap is the closest practical location for measurement of the pump discharge pressure, and is located approximately 11.5 feet above the 3/4-to-2-inch expansion fitting (23.5 feet above the actual pump discharge), and 6.5 feet below the highest piping elevation in the run to the day tank.
As noted above, the 3/4-inch diameter discharge piping run and elevation rise are both approximately 11 feet. The 2-inch diameter fuel oil transfer piping run is approximately
)
177.5 feet with a total rise of 19 feet before entering the top of the HPCS DG day tank.
The only isolation valve in the HPCS DG fuel oil transfer piping is a manual globe valve l
which is located in the highest elevation run of the 2-inch piping shortly upstream of where the pipe enters the day tank.
l Between August 1994 and July 1997, 20 inservice tests were performed and documented for trending purposes. For these 20 tests, the pressure readings at the
{
discharge pressure instrument location ranged from 2.95 to 3.80 psig, which obviously does not reflect the true discharge pressure of the pump. The suction pressure, which is I
calculated utilizing the level of the storage tank, has ranged from 3.51 to 3.80 psig during these tests. The calculated differential pressure utilizing only the discharge pressure instrument and suction pressure has ranged from -0.71 to +0.17 psid. This 4
calculated differential pressure is clearly not representative of the actual pump l
differential pressure.
Based on a '.;ystem resistance calculation for the HPCS DG fuel oil transfer system, the expected pump discharge pressure for the current reference flow rate (36.7 gpm) is 35.4 psig.
Also, based on the same resistance calculation, the pump experiences approximately 75% of the total head loss in the 3/4-inch piping. This would yield an approximate pressure measurement of 8.8 psig at the 3/4-to-2-inch reducer. From the reducer to the pressure instrument tap location, another 5 psi drop is experienced due to the elevation difference alone.
4 Although the actual pressure readings documented during the test period analyzed have l
been in the range expected, the information has provided very little value as a pump degradation tool. The average measured discharge pressure over the analyzed tests is approximately 3.65 psig, with the average suction pressure being approximately 3.68 psig, thus the average differential pressure has been around-0.03 psid. As an attempt to make the differential pressure measurement a more practical pump performance d
indicator, a correction factor was calculated based on the HPCS DG fuel oil system resistance. However, testing experience has indicated that even the use of t, correction 4
I
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 1
PAGE NO. 22 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P81-01 factor has not increased the usefulness of the differential-pressure determinations for this pump, as the following discussion will establish.
The system resistance is based on the flow rate, and therefere the correction factor utilized would need to be based on the system flow rate during the test. This would necessitate setting the flow rate at a fixed value (36.7 gpm being the current reference value), and determining the pump differential pressure, OR setting the differential pressure and determining the flow rate. Both of these test methods are considered to be impractical for the following reasons:
(1)
Flow rate is determined by measuring the day tank level change from the low-i level alarm to the pump shutoff level, and dividing the change by the pump run time. As such, instantaneous flow measurement is not available to allow simple adjustment to establish a fixed flow rate. There are no installed flow meters or taps for measuring flow rate dire::tly. Ultrasonic flow measurement attempts using a portable instrument have proven to be inconsistent when compared to the level change method. The current method for determination of flow rate meets the loop accuracy requirements mandated per Table 1 of ASME/ ANSI OMa-1988 Part 6. Modification to install a flow meter solely for the purpose of providing instantaneous flow indication to allow establishment of a fixed flow rate is not necessary for evaluating the hydraulic condition of this pump for the reasons specified in this relief request.
j (2)
Differential pressure is determined by a calculation of the measured discharge pressure plus the correction factor minus the suction pressure. The suction pressure is from a real-time calculation based on the storage tank level measurement during the pump run. To ensure full loop accuracy, a Barton tube gauge (0-200 inches of water) is 1
utilized to measure the discharge pressure, and thus requires a real-time calculation to i
convert inches of water to psi. Thus, three calculations would be required for each valve j
adjustment to establish a differential pressure. To utilize differential pressure as the fixed i
parameter, each system adjustment to set the differential pressure to the reference value would necessitate the performance of these three calculations. Each performance of these calculations adds time to the pump run duration and unnecessarily increases the potential for calculational error.
(3)
The pump run is typically 9-10 minutes which, as noted above, will not allow for a fixed parameter adjustment during the pump run. Thus, the day tank would need to be drained to the low level for another pump run once the differential pressure is correctly adjusted. The breaker for the pump must be opened in order to drain the day tank to the low level alarm. Unnecessary cycling of component breakers solely for the purpose of performance testing is not desirable.
(4)
The globe valve is the only available means of adjusting the system resistance to J
set either flow rate or differential pressure equal to its reference value; however, 3
1
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 PAGE NO. 23 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P81-01 adjusting the globe valve will change the system resistance upon which the differential pressure correction factor is based. The corresponding resistance factor for the position of the globe valve would need to be determined to re-perform the system resistance calculation, and could necessitate the performance of the system resistance calculation during each pump test depending upon the sensitivity of the valve's resistance factor versus valve position. In either case, valve adjustment would add additional uncertainty to the correction factor applied to the differential pressure measurements, which would further reduce the usefulness of the differential pressure as a pump performance parameter.
(5)
Evaluation of the inservice testing results for this pump has shown that differential pressure measurement is not providing any substantial benefit as a diagnostic tool for pump hydraulic performance.
The current differential pressure reference value for this pump is 33.7 psid, which was based on a system resistance at the old reference flow rate of approximately 35 gpm.
Even though a differen' reference flow rate (36.7 gpm) has been established since the original differential pressure reference value was determined, there has been absolutely no change in the average differential pressure results for the tests at the new flow reference value. If a new reference value is established based on a correction factor at 36.7 gpm, the same test results would be averaged around the new correction factor because of the very little variation between the measured suction and discharge pressures. However, establishing new correction factors or reference values would provide no additional benefit as noted below.
Per Table 3b of ASME/ ANSI OMa-1988, Part 6, the acceptance criteria can deviate from the reference value by as much as 10% (3.3 psi) before corrective action is necessary, in order to achieve a 3.3 psi drop in differential pressure, the measured discharge pressure would have to drop to approximately 0.4 to 0.5 psig since suction pressure remains fairly constant. The pressure drop due solely to the elevation difference between the pressure instrument location and the maximum elevation experienced enroute to the day tank is approximately 2.5 psi. As such, flow would have to drop i
dramatically, and even cease, before the differential pressure ever came close to the j
lower required action value. Therefore, it has become clear that the only parameter which is currently providing any true representation of the pump hydraulic condition is the flow rate.
1 To make the measurement of the pump differential pressure a useful parameter for pump performance evaluation, it would be necessary to perform a modification to install the pump discharge pressure gage closer to the pump discharge. Such a modification is considered to represent an unusual hardship without a compensating increase in the level of quality and safety for the following reasons:
i
- - - _ =
PROGF.AM PLAN NO. GGNS-M-389.1 REVIS!ON NO. 8 2
PAGE NO. 24 OF 26 PUMP RELIEF REQUESTS l
PUMP RELIEF REQUEST NO.: PRR-P81-01 (a)
Any modification would require removal of the fuel oil transfer pump from the i
associated fuel oil storage tank to make the necessary modificatio,1.
(b)
A direct sensing instrument at the pump's discharge flange or the beginning of the discharge pipe would be submerged in the fuel oil with the pump.
For this i
application, a pressure transducer would be required in lieu of a pressure gage. Such an arrangement would necessitato the removal of the pump assembly from the storage tank every time the pressure transducer required calibration.
(c)
If a pressure gage option were used with the tap location at the discharge of the pump and the transducer located elsewhere, the least impact would be caused by i
routing the gage sensing line along with the fuel discharge piping. However, this option would require an additional modification to the existing discharge flange arrangement at the top of the storage tank to allow the sensing line to penetrate the tank (any other penetration location would necessitate an entry into the tank to disconnect the sensing line whenever the pump is required to be pulled for planned or corrective maintenance.)
Once this modification was performed, a correction factor will still need to be catculated to account for the elevation difference between the gage and the pump.
(d)
The current test configuration allows the fuel oil transfer system to be treated as a fixed-resistance system due to the negligible head loss between the current discharge measurement location and the day tank. If a modification were performed to allow for more practical discharge pressure measurement, the system may no longer qualify as a fixed-resistance system depending upon the modification performed. If such were the case, resistance adjustment would necessitate at least two pump runs per quarter as discussed above. The option does exist to keep the drain open on the day tank while the adjustment is made, and then the drain would be shut for the level measurement. This option, however, could significantly reduce the accuracy of the flow rate measurement due to the shorter pump run time and due to the need to measure the initial tank level while the pump is actually filling the tank, instead of during a stable, no-flow condition.
(e)
Safety-related maintenance activities, such as the removal of this pump for any reason, are expensive undertakings and involve risks associated with the disassembly of any piping system.
Performance of a modification requiring such activities will significantly increase the cost burden.
(f)
Working with fuel oil systems involves additional personnel and equipment safety hazards, which should be minimized whenever possible.
(g)
If the transducer option were installed, removal and reinstallation of the pump assembly would be necessary for calibration purposes. This would require additional testing to be performed on the system to ensure that the maintenance activity did not impact the hydraulic performance capability of the fuel oil transfer system. Such testing
4 PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 2
PAGE NO. 25 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P81-01 would require verification that the reference values of the pump hydraulic parameters were not affected. if a transducer arrangement were used, then revalidation of the reference values would be required at the same periodicity as the instrument calibration.
1 (h)
Finally, diesel-generator operability and availability could be adversely affected by an installation of any modification that would require multiple test runs of the fuel oil transfer pump or frequent storage tank entries for calibration purposes should such instrumentation be installed.
Alternative Testing j
As noted in the preceding discussion, the existing means of measuring pump differential pressure does not provide any useful information regarding the pump hydraulic condition that would not be readily apparent by a corresponding decrease in pump flow. For the l
fuel oil transfer system pump, the measurement of flow rate alone, with the following 1
i additional requirements, will provide an acceptable level of quality and safety while having minimal negative impact on diesel-generator operability and availability.
Before starting the pump, adequate stor. ge tank level will be ensured for pump net positive suction head (NPSH) requirements. The system will be left in its normal alignment with no valves throttled. The day tank will be drained to a low level and then
^
refilled using the fuel oil transfer pump. An average flow rate will be calculated and compared to its reference value in order to determine if any pump degradation is t
occurring. A lower " alert value" (not presently required per Table 3b of OMa-1988, Part 6 for centrifugal pumps) of 93% of the reference flow rate value will be established for the pump, if the measured flow rate falls below this " alert value," then the analyses and evaluation actions required by Section 6 of OMa-1988, Part 6 for pump performance in the alert range will be performed.
I Although not specifically provided as alternative testing requirements for this pump, the following summarizes alternative means and supplies for providing fuel oil to the HPCS DG in the event that the fuel oil transfer pump is inoperable. Some of these supplies are more fully described in SAR 9.5.4.
The HPCS DG day tank is equipped with a low level switch that alarms in the Control Room. Various podable electric, gasoline, and diesel-driven pumps are available on-site that could be used in an emergency to refill the day tank by pumping from the storage tank. The HPCS DG installation includes provisions for manually refilling the day tank from outside the Diesel-Generator Building.
Entergy Corp. maintains supplies of diesel fuel at power plants in Vicksburg, MS (approximately 25 miles from Grand Gulf Nuclear Station, GGNS) and in Natchez, MS (approximately 40 miles frcra GGNS). GGNS also maintains a contract with a fuel oil i
i l
PROGRAM PLAN NO. GGNS-M-189.1 REVISION NO. 8 3
PAGE NO. 26 OF 26 PUMP RELIEF REQUESTS PUMP RELIEF REQUEST NO.: PRR-P81-01 supply company in the surrounding area for resupply of HPCS DG fuel oil as part of 4
emergency planning, and the trucks from this company have pumps which could also i
resupply the HPCS DG day tank.
Finally, a fuel oil truck is maintained on-site at GGNS which is normally used for refueling portable diesel engines around the site (e.g., portable pumps, generators, compressors, etc.) The truck has 1,100 gal capacity and can be refilled from an on-site storage tank.
The truck could be used in an emergency to refill the fuel oil day tank, even though neither the quantity nor the quality (purity and chemical analysis) of the fuel oil in either the truck or the storage tank is controlled for emergency purposes.
l
>