NRC-88-0142, Provides Addl Info Re IE Bulletin 85-003 Re motor-operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings,Per 880328 Request.Confirmation Testing of Torque Switch Settings Being Conducted
| ML20153G041 | |
| Person / Time | |
|---|---|
| Site: | Fermi  |
| Issue date: | 05/04/1988 |
| From: | Orser W DETROIT EDISON CO. |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| CON-NRC-88-0142, CON-NRC-88-142 IEB-85-003, IEB-85-3, NUDOCS 8805110123 | |
| Download: ML20153G041 (12) | |
Text
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.. n Edison Egips 1r mL May 4, 1988 NRC-88-0142 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C.
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References:
1)
Fermi 2 NRC Docket No. 50-341 NRC License No. NPF-43 2)
NRC IE Bulletin 85-03, "Motor-Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings."
3)
Detroit Edison Letters to the NRC in response to IE Bulletin 85-03 dated May 15. October 1. December 19, 1966 and November 17 and December 9,1987.
4)
NRC Letter to Detroit Edison dated March 30, 1988 requesting additional information regarding IE Bulletin 85-03.
5)
BWR Owner's Group Letter No. 8815/0TR1, dated March 28, 1988.
Subject:
A ditional Information Regarding IE Bulletin 85-03 d
In response to the NRC letter duted March 30, 1988 (Reference 4) which was received on April 4,1988, Detroit Edison provides the additional information requested regarding our previous responses to the IE Bulletin 85-03 (Reference 3).
The NRC questions and their response are provided in Enclosure 1 of this letter. Enclosure 2 addresses the deletion of RCIC Valve E5150F059 frca the program.
If you have any further questions, please contact Mr. Girija Shukla at (313) 586-4270.
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8805110123 880504 PDR ADOCK 05000341 O
PDR Enclosures Q
cc Mr. A. B. Davis Mr. R. C. Knop Mr. T. R. Quay
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Mr. W. G. Rogers 1
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USNRC May 4, 1988 NRC-88-0142 Page 2 l
I, WILLIAM S. ORSER, do hereby af fitt.: that the fc,regof9g statements are based on facts and circumstances which are true an*5 eccurate to the best of my knowledge and belief.
l Nk Y
WILLIAH S. ORSER Vice President Nuclear Operations on this b
day of k
1988, before me personally appeared William S. Orser, bei g ret duly sworn and says that he executed the foregoing as his free act cnd deed.
f NotaryPflic f
SHIRuiV L CMMON Notary Putple, Wayne County, Mi MrCommiedon E@es*R M I
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NRC-88-0142 Page ?
RESPONSE TO NRC REQUES'l FOR ADDITIONAL INFORMATION (RAI)
REGARDING I2 BUILETIN 85-03 istC OuestionJ "If MOVATS is planned for application to some MOVs which are not included in its data base, commit to and describe an alternate methed for determining the extra thrust necessary to overcome pressure differentials for these valves."
Response to Question 1:
Confirmation testing of MOVs is being performed in complience with Bulletin 85 03 Action item c.
Recommended torque switch settings for the MOVr. are tested to measure actual thrust capability against expected actuator performance. The MOVATS database includes a sufficient number of sample MOVs which are similar to Fermi 2 MOVs.
Only one RCIC valve with a passive function is not comparable to any MOVs in the MOVATS database.
This MOV is being deleted f rom the Fermi 2 response program as discussed iti Enclosure 2.
' Extra' thrust appears to mean a deficiency in the maximum MOV design differential pressures (dPs). The Fermi 2 Bulletin 85-03 response pregram has included recalculation of maximum dPs and adjustment to revised torque switch settings for the HFCI and RCIC MOVs with active functions. This was described in our November 17, 1987 response to Bulletin 85-03 Action items a and b.
The recalculated dPs generally confirmed that the original engineering applications were correct. It is assumed that the valve and actuator manufacturers have sufficient design knowledge to correctly determine size and specify control settirgs for the motor actuators. Therefore, no alternative method of
' extra' thrust determination is required.
i
NRC-88-0142 Page 2 NRC Question 2:
"Revise Table 1 of the response dated 11-17-87 t' include values of differential pressure for opening the followint 10Vs, or justify exclusion of these pressures. As required by Action Item a of the bulletin, assume inadvertent equipment operations."
Response to Question 2:
Table 1 of our response dated November 17, 1987 will be updated to provide complete data for all MOVs. As committed in that response, a final report will be submitted no later than ninety (90) days af ter the LLRT Cutage ends. This report will include the updated Table 1.
Fermi 2's response program for Bulletin 85-03 is based upon the GE/BWROG report, NEDC-31322, dated September 1986. Action Item a of Bulletin 85-03 required assumption for "determining the maximum differential pressure, those single equipment failure and inadvertent equipment operations that are within the plant design basis".
In discussion with the BWROG, it was stated by the NRC that inadvertent valve operation is outside the BWR design basis. At NRC request the BWROG is performing a further evaluation of selected HOVs mispositioning (Reference 5).
The four (4) MOVs listed under this question are included in the selected MOVs being evaluated by the BWROG.
In brief, the following response is provided to the questions on *hese four MOVs based upon the Fermi 2 specific design.
(a) E4150F004, HPCI MOV 3. CST Suctier. Isolation Valve - receives an opan signal when HPCI auto-initiation signal is presenti can also be closed or opened by remote pushbutton, Maximum differential pressure (dP) calculated for testing is 104 psid and the original design dP is 75 paid.
This valve performed satisfactorily during confirmation testing which was based upon calculated dP.
(b) E5150F010 RCIC MOV 3 CST Suction Isolation Valve - receives an open signal when RCIC auto-initiation signal is present and can also be closed or opened by remote pushbutton.
Maximum calculated dP is 42.6 paid and the original design dP is 60 paid. This valve performed satisfactorily during confirmation testing which was based upon the original dP.
(c)
E4150F021. HPCI MOV VI. Turbine Exhaust Steam Isolation Valve
- can be opened and closed by remote pushbutton. Maximum calculated dP is 25 paid, original design dP is 125 paid.
)
NRC-88-0142 Page 3 This valve performed satisfactorily during confirmation testing which was based upon the origina'. dP.
(d) E5150F001. RCIC MOV VI. Turbine Exhaust Steam Isolation Valve
- can be opened and closed by remote pushbutton. Maximum calculated dP is 25 paid, original design dP is 150 paid.
This valve performed satisfactorily during confirmation testing which was based upon the original dP.
l Fermi 2 will review and respond to the BWROG generic evaluation of selected MOVs when the evaluation is completed.
NRC Question 3:
"Revise Table 1 of the response dated 11 87 to include RCIC MOV F044, or justify its exclusion. This MOV governs the RCIC Turbines it is shown normally open in Zono D-10 of drawing 6M721-2045 Revision Q."
Response to Question 3:
E5150F044. RCIC Turbine Governor Control Valve, is a '
hydraulic-operated valve (HOV); the designation on drawing 6M721-2045 is incorrect.
The valve is a part of the turbine hydraulic governor r
system manufactured by Woodward Governor Company. It is not subject to IE Bulletin 85-03 testing, NRC Question 4:
"Revise Table 1 of the response dated 11 87 to include values of differential pressure for opening the following valves, or justify exclusion of these pressures. According to pages 55 and 59 of the l
BWROG Report, each of these valves has a safety action for opening.
"N/A" is listed for both entries of differential pressure.-
{
(a) E?CI MOV F012 is shown normally closed as MOV 2 on Page 68 of the BWROG Report.
(b) RCIC MOV F019 is shown normally closed as MOV 2 on Page 72 of the BWROG Report."
Response to Question 4:
HPCI MOV 2. E4150F012 used a calculated 1306 psid for both closing and opening dP.
RCIC MOV 2. E5150F019. used line pressure of 1280 paid for opening dP and a calculated 1268 paid for closing dP.
1 J
NRC-88-0142 Page 4 Fermi 2 used a more specific definition of "active safety function" regarding Bulletin MOVs than is applied in the report, NEDC-31322.
Fermi 2 considers the opening function of the two (2) subject. MOVs to be important to component protection. The "N/A" does not mean the MOVs were not to be tested for that stroke direction.
HPCI and RCIC MOVs are considered to perform active safety function for either of:
1.
Opening from normal lineup to inject high-pressure makeup into the PRV; or 2.
Closing from operating mode or lineup in response to valid isolation or trip signals.
Notwithstanding the above definition, Fermi 2 is testing the applicable MOVs in both opening and closing direction. Detai3 s of the tests and results will be submitted as committed in our response dated November 17, 1987 ninety (90) days af ter the end of the LLRT Outage.
The updated Table 1 will also identify stroke-directions of any subject MOVs considered important to component protection.
NRC Question 5:
"The proposed program for action items b, e and d of the bulletin is incomplete. Provide the following details as a minimums (a) commitment to justify continued operation of a valve determined to be inoperable, (b) description of a method possibly needed to extrapolate valve stem thrust determined by testing at less than maximum differential pressure, (c) justification of a possible alternative to testing at maximum differential pressure at the plant, (d) consideration of pipe break conditions as required by the
- bulletin, (e) stroke testing when necessary to meet bulletin requirements, and (f) consideration of applicable industry recommendations in the preparation of procedures to ensure maintenance of correct switch settings."
l Response to Question 5 (a):
I l
Continued operation with an inoperable component is subject to a Fermi 2 Deviation Event Report (DER) disposition for remedial corrective action.
In addition, confirmation testing of MOV torque switch 1
NRC-88-0142 Page 5 settings for the Bulletin 85-03 response includes a diagnostic test of overall MOV performance.
Confirmation test evaluations of MOVs for Bulletin 85-03 receive an engineering verification of valve performance. A design document has been established to provide expected performance criteria for these tests. Degradations identified under this review may also be reported in DERs and evaluated for potential inoperable conditions.
Response to Question 5 (b):
Confirmation testing of torque switch settings at Fermi 2 is being conducted with the MOVATS test system. Under contract, MOVATS, Inc.
has also provided Fermi 2 a set of target thrusts. These target thrusts represent the upper bound values of single database samplings analyzed for 90% confidence intervals.
The MOVATS target thrusts and the manufacturer's calculated torque and thrust requirements provided for each actuator are used as relative measures of expected MOV performance.
Specific evaluation will be made of the performance at the torque switch setting corresponding to the maximum dP requirement. Additional evaluation of available thrust margin is made by testing up to the limiter plate value of the torque switch. The highest torque available before control switch trip is at the limiter plate setting.
Response to Question _5 (c):
It is Fermi 2's position that the design methods and capabilities of the valve and actuator manufacturers are conservative. The valve stem thrust requirements, actuator size and control settings are adequate for the maximum dP originally specified.
Revised dPs for IE Bulletin 85-03 will require some MOV assembly upgrading. Testing performed to date has shown that improved thrust margins are available by spring pack changeout to increase the torque spring duty rating of four (4)
MOVs.
In addition, as noted in our response dated November 17, 1987, testing with a MOV diagnostic system has several advantages. The MOVATS test ayatem has been reviewed and approved by the NRC (NUREG 4380).
Diagnostic testing under static conditions is fully capable of determining available operator thrust. Diagnostic testing under static conditione allows immediate evaluation, correction and retesting for MOV degradations.
This is because system or component availability is not in question.
NRC-88-0142 Page 6
.l As noted under response 5 (b), Fermi 2 is evaluating specific performance of each MOV at the manufacturer's recommended torque switch setting. The available thrust margin is also evaluated up to the limiter plate setting. The goal of the Fermi 2 program is to establish sufficient thrust margins to account for expected thrust degradations during plant operational periods.
Periodic retesting will be performed if maintenance activities could result in a loss of available thrust. A complete description of the Fermi 2 long-term program will be provided in the final report, due ninety (90) days after the LLRT Outage ends.
Based upon maintaining thrust required by the design, and confirmed by diagnostic testing Fermi 2 believes that dynamic testing is unnecessa ry.
The stated purpose of the bulletin is (for licensees) to develop and implement a program to establish and maintain correct switch settings on motor-operated, safety-related valves. The Bulletin further requires a review of the engineering applications used for the af fected MOVs to ensure that maximum differentisi pressures calculated for expected MOV functions envelope the complete design bases (normal and abnormal events) for the plant. Dynamic testing is a design engineering responsibility, in regards to the Bulletin requirements, performed by the original manufacturer. Fermi 2's responsibility, to ensure that originally supplied design parameters are maintained, is accomplished by the diagnostic testing performed.
l Response to Question 5 (d):
s Evaluation of worst-case differential pressures was performed generically by the BWROG and is contained in report NEDC-31322 September 1986. Fermi 2 has followed up with a specific plant design calculation (DC) No. 4685. Because these evaluations envelope the plant design basis, consideration for pipe break conditions is inherent.
Response to Question 5 (e):
All 17 of the subject HPCI MOVs and 11 of 16 sub;ect RCIC MOVs in the Fermi 2 response to Bulletin 85-03 are included in the plant's ISI Pump and Valve Progrcm. In addition, as noted in response 5 (c),
retesting to verify thrust available will be performed when maintenance activities could result in a loss of thrust. A complete 4
description of the Fermi 2 long-term program will be provided in the j
final report, due ninety (90) days af ter the LLRT Outage ends.
I
Page 7 i
Response to Question 5 (f):
Fermi 2 maintains active contacts with the BWROG INPO. EPRI and the valve and' actuator manufacturers. Fermi 2 also communicates with other nuclear power plants on specific issues regarding IE Bulletin -
85-03.
Further. Fermi 2 continues to evaluate available diagnostic l
and monitoring technologies. Information gained'from all of.these t
sources will be used in Fcrui 2's long-term program for maintaining correct control switch settings.
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UPDATE TO FERMI 2 IE BULLETIN 85-03 RESPONSE PROGRAM l
DELETION OF E5150F059. RCIC MOV X l
MOV E5150F059 will be deleted from the Fermi 2 long-term response program for IE Bulletin 85-03.
The BWROG report, NEDC-31322. Table 4 notes that this valve has an active safety action to closa. This closure is on a turbine overspeed trip which is effected by a mechanical latching and spring closure subassembly. Section 3.3.4.15 of NEDC-31322 states this MOV was included "for the purpose of completeness" because it was in the ASME XI program of some plants.
Likewise Fermi 2 has tested this MOV during Outage 88-01 for completeness of the initial test program. This valve, however, is not part of Fermi 2's ASKE Section XI ISI program for pumps and valves.
E5150F059 is a Shutte & Koerting Company, 3" X 4" Top Mechanical Throttle and Trip Valve. The valve was originally supplied as part of the RCIC turbine assembly. An extract of the relatching operation is attached. The Limitorque motorized actuator serves two functions for the operation of the valve. First, it is primarily used for the relatching and valve resetting function. The screw spindle is a fixed, hollow shaft with internal and external threads. The internal threading drives the valve stems external threads are driven by the l
actuator. This stem is non-rising and cannot be used to calibrate thrust-to-spring pack displacement, as required for the MOVATS 2150 j
Test System.
On turbine trip, the E5150F059 closure spring provides a downward impulse to the valve stem. The flow-over-disk configuration assures closure and tight seating. The upstream MOV, E5150F045 (MOV 1), RCIC Steam Admission Valve, closes subsequently to turbine trip.
Steam pressure on both sides of E5150F059 is vented to the barometric
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condenser. Relatching is a local-manual activity coordinated with the control room for actuator positioning. The maximum opening force i
experienced by the actuator is that required to compress the trip-closure spring, i
The second function of the actuator is for using E5150F059 as a manual turbine throttle. This was intended to be used from a second division i
remote shutdown panel. A startup test (STUT.01A.028) was performed which demonstrated this throttle capability. The second division remote shutdown panel has since been removed from service.
Starting i
RCIC with E5150F059 has been demonstrated to be unreliable; all starts use the electro-hydraulic governor valve. E5150F044 and steam admission valve E5150F045. Any throttling performed will begin with the valve in the full-open position.
NRC-88-0142 Page 2 t
In summary, E5150F059 closes on spring force and upstream pressure.
It opene during valve manual-relatching/ reopening only against the trip closure spring force. RCIC operation, particularly startup or trip, is independent of the E5150F059 motor-operated capacity for 4
opening or closing the valve. Therefore, this valve does not meet the criteria for inclusion in the IE Bulletin 85-03 response program and will be deleted from the program. No further programmatic testing will be performed'on R5150F059 for the IE Bulletin 85-03 long-term response.'
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w _an_n m Page 3 VA4g4_jgJg m A(7, OPQ1ATI!!G PRil CIPLE After trippin.;, run the operator to the closed position.
The ro-tation of tha screw coindle uill nevo tha sliding nut to return the
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latch up lover (cart 27) to its relatcr.ing positicn.
To relatch, the i
latch heck must be reJeased to per.'it the u.aip hock (part 23) to rotate and hold the latching lever.
l Af ter the.Tatchi:.g lever has l'een engaged with the trip hook and The end of the coupling (g direction, the disc is lifted from in the openin the operator is turned part 7) acts as a limit stop contact the seat.
with the bottom of the sliding nut (part 47).
These parts, even though
,jarerned, move dovn>/ard together when the valve is trj.pped, and cannot.Lm-pede the free closing motion of the valve.
In no case is the top of disc permitted to come in contact with the underside of the va*1ve cover as that would irr) pose a heavy reaction "load l
on the trip hook which the trip gear would be unable to d.isengage.
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IDE*TITY LIST FOR 3" TOP !ECH. '...Thl'tL TRIP VALVE 3
Part Port f.'o.
DescrMtion I *o.
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leak nrr Bushirg 35 Flat setserew 9
Yoke rianse 36 Holle:i Iockacrew 10 Flexitollic Gasket 37 coc. Pipe Plug 11 Strainer Hacket 38 Ficxitallic Gasket i
12 Seat 39 studs 13 Leak off Buchinn 40 Hex Iuts 14 Bottom Stuffing Box 41
- .*dl. Setscrew 15 switch Mounting Flate 42 Intching Pin 16 Soc. Hdl. cotscrew(cone point) 4443 Soc. Hd. Capscrews 17 Trip Hook Pin Yoko Nut L
18 Hex !!uts 45 Cerpression spring 19 Spring Pin 46 Alem.ite Fitting 20 S:titch Assembly 47 Sliding Nut O
21 Washers 48 Cover with Cylinder
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22 Linitorque Motor Operator 49 Body
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23 Trip Hcok 50 Disc 24 Cor.pression Spring 51 Pilot Valve with Sten 25 Radius lover 52 Std. Pipe Plug 26 Hdl. Setscrew 53 Link Pin / cotters 27 Latching up Lever 54 Std. Pipe Plug 1
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