ML20214E492
| ML20214E492 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 05/18/1987 |
| From: | Andrews R OMAHA PUBLIC POWER DISTRICT |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| TAC-64236, NUDOCS 8705220109 | |
| Download: ML20214E492 (10) | |
Text
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Omaha Pubile Power District 1623 Harney Omaha, Nebraska 68102 2247 402/536 4000 May 18, 1987 LIC-87-313 U. S. Nuclear Regulatory Commission l
Document Control Desk Washington, DC 20555
References:
1.
Docket No. 50-285 2.
Letter NRC (W. A. Paulson) to OPPD (R. L. Andrews) dated April 20, 1987 Gentlemen:
SUBJECT:
Additional Information on Auxiliary Feedwater System Reliability Analysis (TAC No. 64236)
Please find attached, the additional information on the Fort Calhoun Station Auxiliary Feedwater System Reliability Analysis requested by Reference 2.
If you have any questions, please contact us.
Sincerely, R.d. % %
R. L. Andrews Division Manager Nuclear Production RLA/me cc: LeBoeuf, Lamb, Leiby & MacRae 1333 New Hampshire Ave., N.W.
j Washington, DC 20036 R. D. Martin, NRC Regional Administrator W. A. Paulson, NRC Project Manager P. H. Harrell, NRC Senior Resident Inspector 8705220109 e7o518 DR ADOCK 0500 S
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d I esponses to Questions on Fort Calhoun Station, Unit No.1 R
~. Auxiliary Feedwater System Reliability Analysis
.NRC Ouestion:!
c
-1.
Please ' provide basis for assuming that ' plant-specific -data developed =
for Calvert Cliffs is applicable to' Fort Calhoun.
In:particular, are:
there test and maintenance-data to support the use_of a failure i-
. probability for.a.. turbine driven pump that is an order of magnitude smal.ler. than the generic value?-
OPPD Response:
The Calvert Cliffs IREP data'was used in the Fort Calhoun AFW System 4.
Reliability Study for the following reasons:
,I (1) A consistent set of failure data was required for the analysis. -
1 (2) Th'e Calvert Cliffs' and Fort Calhoun plants are from the same -
1.
. generation of CE plants and have similar operating histories, evidencing high availability.
(3)
Fort Calhoun component reliability data does not imply that the unavailability of a component might be too low when using the Calvert Cliffs data.
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A summary of the maintenance history for FW-6, FW-10, HCV-1107A,-
HCV-11078, HCV-1108A, HCV-11088, YCV-1045,'YCV-1045A and YCV-1045B as
)
requested in the April 8, 1987 conversation between the NRC, their--
contractor Science Applications International Corp. (SAIC):and OPPD is contained in Table 1.
j Since the AFW system is in general required only during start-up and i
power operations-(upon an automatic actuation basis),. maintenance performed during refueling outages. (when decay heat removal' is accomplished through the shutdown cooling system) is not ' included.and
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not appropriate for evaluating component availability.
1 Table 2 contains a listing of the. surveillance test ST-FW-1Lresults I
for FW-6 and FW-10 during periods when RCS heat removal-was performed by the steam generators and covers the peried of June 1977 to the present. Until January 1985, this-testing was performed on a quarterly basis.
In order to provide additional assurance of AFW system operability, the surveillance test interval was reduced'to monthly. Another improvement in testing was made in January 1984 when specific acceptance criteria including allowable flow rate' bands and action levels were added'to the' procedure. Teble 2 shows'that both FW-6 and FW-10' started and performed ' acceptably during a11' testing.
Problems identified (in.the footnotes)'did not result ~ in removing either of the_ pumps from service for corrective maintenance.
It-should be noted that FW-6 and the ~as' ociated flow paths are not-only s
exercised during surveillance testing, but also during'each startup>
and shutdown. No failures have occurred during these applications of the AFW' system..
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' Specifically addressing the AFW pumps, a review of the operating histories of both pumps did not provide any evidence that use of the Calvert Cliffs data would be non-conservative or lead to results not applicable to-Fort Calhoun. While the number of challenges associated with the steam turbine driven pump at. Fort Calhoun is somewhat less than that with the turbine driven pumps at Calvert Cliffs, a fact that could suggest the use of a higher unreliability, the lack of any failures-indicates that there is no reason to suspect that the Fort Calhoun pump is any less reliable than the Calvert Cliffs pumps.
[
TABLE 1 MAINTENANCE HISTORY (1974~to present)
Duration of-Equip.
Component Qalg Outaae (Hours)
Cause/ Comments FW-6 (1) 6-14-79 6.08 Clean and inspect motor (2) 7-23-80 4.50 Leak on capnut.
Installed washer
-Total = 10.58 FW-10 (1) 4-16-74 2.75 011 line to governor leaking.
(2) 7-3-74 1.17 Replace oil sensing line on governor (3) 9-21-78 1.75 Change oil (4) 12-30-86 5.25 Adjust mechanical linkage Total - 10.92 HCV-1107A 6-19-80 48.67 Replaced failed Valcor solenoid. Valve was failed in open position which is the fail-safe position and would have permitted AFW flow to l
the SG.
HCV-1108A 7-17-80 8.00 Replaced failed Valcor solenoid. Valve was failed in open position which is the fail-safe position and would have permitted AFW flow to the SG.
YCV-1045 0.00 No maintenance, resulting in r
YCV-1045A out of service condition, YCV-1045B performed during periods when YCV-11078 decay heat removal accom-YCV-1108B plished by steam generators.
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TABLE 2 SURVEILLANCE' TEST ~(ST-FW-1) RESULTS HISTORY (June'1977 to present)-
Datg FW-6 (Pass / Fail)
FW-10 (Pass / Fail)-
6-29-77 Pass Pass 9-30-77 Pass Pass 11-24-77 Pass Pass 1-4-78 Pass
' Pass 3-29-78 Pass Pass.
6-28-78 Pass Pass 10-4-78 Pass Pass 1-3-79 Pass Pass 4-4 79
. Pass Pass 7
- 79 Pass Pass 10-3-79 Pass Pass 1-2-80 Pass Pass 7-1-80 Pass Pass 9-30-80 Pass Pass 12-30-80 Pass Pass 3-31-81 Pass Pass 6-30-81 Pass Pass 3-30-82 Pass Pass (1) 6-1-82 Pass
' Pass 6-29-82 Pass Pass (2)'
9-28-82 Pass Pass 12-29-82 Pass Pass (3) 3-29-82 Pass Pass 6-28-83 Pass Pass 9-27-83 Pass Pass
}
1-3-84 Pass Pass 1-19-84 Pass Pass 7-16'84
. Pass 7-18-84 Pass 10-2-84 Pass Pass 1-1-85 Pass Pass 1-29-85 Pass Pass 2-26-85 Pass Pass 4-2-85 Pass Pass j
4-30-85 Pass Pass 5-28-85 Pass Pass 7-2-85 Pass Pass 7-30-85 Pass Pass 9-3-85 Pass Pass._.
~
a DAlg FW-6 (Pass / Fail)
FW-10'fPass/ Fail)
Performed under ST-FW-1.(F.2) continued:-
12-31-85 Pass Pass 1-28 Pass Pass 2-25-86 Pass Pass-
, 1-86' Pass Pass 4-29-86 Pass
-Pass-6-3-86 Pass Pass 7-29-86 Pass
' Pass 8-12-86 Pass
. Pass 9-2-86 Pass-
' Pass 10-1-86 Passi
-Pass 10-28 Pass.
Pass-12-2-86 Pass.
. Pass-12-30-86 Pass Pass 2-3-87 Pass Pass 3-3-87 Pass Pass Note:
Pass indicates that:
(a) FW-6 was successfully started and stopped from both the control room (CB-10/11) and the control room AFW panel AI-66A and the pump performed in accordance with the' acceptance criteria of ST-FW-1 under which the test was performed.
(b) FW-10 was successfully started and stopped from both'the control room AFW panel AI-66B and the alternate AFW panel AI-179 and the pump performed in accordance with the acceptance criteria of.
ST-FW-1 under which the test was performed.
(1)
FW-10 trouble annunciator, initially indicated problem; cleared while running.
(2)
FW-10 started when switching.back to remote.
(3)
AI-668 light for FW-10 did not show when pump running.
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a NRC Ouestion:
- 2.-
Please provide the test intervals for each component.
In particular, provide valve stroke and position' checks for all of the valves, o
especially the valves on the auxiliary feedwater injection path that -
are not necessarily tested during;the monthly pump tests.--
- ^
OPPD Resoonse:
+
Section F.l'of ST-FW-1, performed on 'a monthly interval, independently i.
verifies auxiliary feedwater system valve alignment. Valves FW-339, FW-1316, FW-349,-FW-172, FW-350 and FW-171 are verified to be locked open while valves HCV-1107A,:HCV-1107B, HCV-1108A, and HCV-1108B are iverified to be closed and in the AUTO mode. Verification is also.
conducted to ensure YCV-1045 is closed and in the AUTO mode and valve HCV-1384 is closed.
I Section F.2 of ST-ISI-FW-1, performed on a quarterly basis, measures the: stroke times'of valves HCV-1107A,_HCV-11078, HCV-1108A, HCV-1108B-and HCV-1384.
For. valves located outside containment, the measurements
'are made locally.
For valves located inside containment,. measurements are made by observing the position indicator lights.
If containment is accessible, the measurements are made locally.
NRC Ouestion:
3.
Your analysis included failure to restore valves to the proper posi-i tions after maintenance but did not include equipment unavailability due to equipment being out-of-service during maintenance. Was this an omission or do plant practices or maintenance data indicate that this is a negligible contributor to component unavailability?
OPPD Resoonse:
i Unavailability contributions due to maintenance were not specifically-included in the fault tree model for, the followir.g reasons.
[
(1) A review of the maintenance history of the two AFW pumps indicated,
i that the contribution to unavailability resulting-from maintenance 1
is small compared:to that associated with random failures - well-within the range of the assumed uncertainties.:
i (2) The data presented in Tables 1 and 2 indicate that no AFW valves have been taken out of service for maintenance following sur-veillance testing.
i NRC Ouestion:
4.
Your fault tree indicates that valves FCV-1101, FCV-1102, HCV-1103 and HCV-Il04 close on a loss of main feedwater and must be reopened to use the main feedwater lines as injection paths for the AFWS.
Please '
confirm that this is correct.
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0 PPD Response:
Since no specific initiating events were assumed.in the analysis,-the initial condition of the MFW flow path valves was assumed to be the.
most conservative with respect to system unavailability.
All of the specified valves are " fail as is"'(FAI) with respect to a -
loss;of power to their actuators..For a loss of power initiator during power operation,=the valves would remain open.
For-a loss of main-feedwater due to a control. system or actuation system fault'(e;g.,-
~
inadvertent SGIS) the valve (s) may or may not be closed.: ' Therefore, -it was conservatively assumed that these four valves would close..
NRC'Ouestion:
5.
Please provide a listing of power sources for'the AFWS components.
This listing should include the AC or DC power supplies for the. A0V's.
and MOV's, the DC control power, source for-the pumps and the source of.
power.for the motor driven pump upon loss of offsite power.
OPPD Resoonse:
The requested information is summarized in Table 3.
For air operated valves, the power supply corresponds to that of the associated solenoid.
It should be noted that the analysis intentionally did not consider loss of power initiators'since it is beyond the scope of the SRP requirements and not necessary for this verification.
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I TABLE 3 COMPONENT POWER SUPPLIES VALVES: Main Feedwater System Flowpath Emergency Valve 'D A0V or MOV fail Position' Power-Sunoly Power Supolv
-FCV-1101 A0V FAI 120 VAC, 1 phase AI-40D_ Inst.
AI-40C Inst. Bus Emergency Bus through trans-fer switch 108-100 to power distri-bution AI-10A D2 FCV-1102 A0V FAI 120 VAC, 1 phase AI-40C Inst.
AI-40D Inst. Bus Emergency Bus through trans-fer switch 10B-100 to power distri-
~bution AI-108 D1 HCV-1103 MOV FAI 480 VAC, 3 phase MCC-3Al none HCV-1104 MOV FAI 480 VAC, 3 phase MCC-4C1 none HCV-1105 A0V FC 10-50 mA DC signal from LIC-903Y at Control Room Panel CB-10 (AI-42A) none HCV-1106 A0V FC 10-50 mA DC signal from i
LIC-906Y at Control Room
'i Panel CB-10 (AI-42B) none HCV-1384 MOV FAI 480 VAC, 3 phase none MCC-4C1 HCV-1385 MOV FAI 480 VAC, 3 phase MCC-3Al D1 HCV-1386-MOV FAI 480 VAC, 3 phase 1
MCC-4C1 D2
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! VALVES:.duxiliary Feedwater System Flowpath SolenoidandL Emergency.
-Valve ID A0V or MOV Fail Position Power-Sunolv Power Sunolv HCV-1107A-A0V' F0
.DC #1-none HCV-1107B A0V F0_
--DC.#2 DC#1 thru AI-179
' transfer switch:
HCV-1108A A0V F0 DC.#1-none HCV-1108B A0V.
F0 DC #2
.DC#1 thruiAI-179 transfer switch YCV-1045 A0V F0 '
DC #2' DC#1 thru AI-179.
transfer: switch YCV-1045A-A0V F0 DC #2 DC#1 thru AI-179 transfer switch-YCV-1045B A0V F0 DC #2 DC#1.thru AI-179 transfer: switch PVMPS:
Pumo ID Power Sunolv Emeraency Power Supply FW-6 4160V Bus IA3 Diesel Generator D1 FW-10 Mainsteam/ Lube oil pump
- Initial steam valve control pressure only until main turbine driven lube oil' pump builds up enough' pressure.
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