ML20205B800
| ML20205B800 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 07/30/1986 |
| From: | Cutter A CAROLINA POWER & LIGHT CO. |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| IEB-85-003, IEB-85-3, NLS-86-269, NUDOCS 8608120152 | |
| Download: ML20205B800 (7) | |
Text
a Y\\'
}kt Carolina Power & Light Company SERIAL: NLS-86-269 JUL 3 01986
'..,;. 01 Dr. J. Nelson Grace, Regional Administrator United States Nuclear Regulatory Commission Suite 2900 101 Marietta Street, NW Atlanta, GA 30303 H. B. ROBINSON STEAM ELECTRIC PLANT, UNIT NO. 2 DOCKET NO. 50-261/ LICENSE NO. DPR-23 RESPONSE TO IE BULLETIN NO. 85-03 " MOTOR-OPERATED VALVE COMMON MODE FAILURES DURING PLANT TRANSIENTS DUE TO IMPROPER SWITCH SETTINGS"
Dear Dr. Grace:
Carolina Power & Light Company (CP&L) hereby submits information requested by IE Bulletin No. 85-03, " Motor-Operated Valve Common Mode Failures During Plant Transients Due to Improper Switch Settings," dated November 15,1985. This information is being provided within the time frame stated in CP&L Letter NLS-86-269, submitted to you on May 7,1986. The subject Bulletin required that a design basis review be performed and a program be developed and implemented to ensure that switch settings for certain safety-related motor-operated valves (MOV) are properly selected, tested under simulated conditions, and correctly maintained.
This submittal provides the results of CP&L's review, per action (a) of the Bulletin, of the design basis for the operation of the MOVs in the high pressure components of the Safety injection System and the Auxiliary Feedwater System. In addition, a descrip(d) of tion of the program and an implementation schedule for completing actions (b) through the Bulletin are included. The attached information is formatted such that the specific subheadings correspond to the Bulletin item topics.
A final report will be submitted within 60 days of the completion of the IEB 85-03
~
requirements, but no later than January 15,1988.
Should you have any questions regarding this submittal, please contact Mr. Arnold Schmich at (919) 836-8759.
Your ery tr
/lfA V
./, -
A. B. Cutter - Vice Pr ident ABC/AWS/vaw (4018AWS)
Nuclear Engineering & Licensing l
Attachments cc:
Mr. G. Requa (NRC)
Mr. H. Krug (NRC Resident inspector - RNP) l A. B. Cutter, having been first duly sworn, did depose and say that the information contained herein is true and correct to the best of his information, knowledge and bel m e.,,
and the sources of his information are of ficers, employees, contractors, and agen g
R4 Carolina Power & Light Company.
e.
Yt2/)nll
%DTAW o
1 3
My commission expires: 5-/B 86 Notaty (Seal) l
[
e4 j
k.'2(1800
)
8608120152 860730 "He street
- P O Boa 1551
- Aaseign N C 27602
- e...***
PDR ADOCK 05000261 n g g j,t c OljNT*
G PDR F
seemion',
Y
RESPONSE TO NRC IE BULLETIN 85-03 The following sections provide specific detail on each of the IEB 85-03 action items:
A.
Design Basis Information The Westinghouse Owners Group, of which CP&L is a member, developed a program to address action (a) of the Bulletin on a generic basis. The " Westinghouse Owners Group Safety-Related MOV Program Final Report," dated April 7,1986, provided this generic methodology. After review by CP&L, this information was used to develop a plant-specific MOV review program for H. B. Robinson, Unit No. 2.
CP&L reviewed the MOVs in the high head portion of the Safety injection System (515) and the Auxiliary Feedwater System (AFWS) and identified the valves listed in Table 1 as being subject to the requirements of this Bulletin. Table la provides the justifications for the determination of maximum operating differential pressures for subject MOVs.
Table 2 provides the list of MOVs that are included in the high head SIS and AFWS, but are excluded from the Bulletin requirements.
In addition, justification for their exclusion is provided.
The valves in the SIS are those valves which are positioned by the Engineered Safety Features Actuation System (ESFAS) during the high pressure coolant injection phase.
The valves in the AFWS and Main Steam (MS) system listed in Table 1 are those valves which are: (1) positioned by ESFAS to actuate or direct flow to the steam generators from the motor driven auxiliary feedwater pumps and steam driven auxiliary feedwater pump, or (2) positioned to isolate auxiliary feedwater from the faulted / ruptured steam generator during a main steam / feed line break or steam generator tube rupture event.
The function of each respective valve and a reference to the applicable FSAR figure are indicated in Table 1.
In Table 1, the maximum operating differential pressure was compared against the valve design specification differential pressure to verify adequate design. The maximum operating differential pressures were obtained from evaluating the system configuration, system operating mode, and design basis event for each valve. Therefore, the maximum operating differential pressure is the realistic differential pressure that is expected for the valve operaiion during normal and abnormal events. The design bases for these systems are contained in FSAR Sections 6.3 (SIS) and 10.4.8 (AFWS).
B.
Switch Settings Torque switch settings are currently being evaluated in accordance with the requirements of the Bulletin for the valves listed in Table 1.
In addition, the torque switch bypass position limit switch selection and the thermal overload protection setting methodology are under review and evaluation.
The determination c,f the correct switch settings is scheduled to be completed prior to an upcoming H. B. Robinson, Unit No. 2 refueling outage currently scheduled for March 1987. Once the switch settings are determined, the valves will be tested in accordance with the Valve Testing Program (Part C, below), and the test results will be reviewed and assessed. Any alterations to the switch settings, as a result of the tests performed, will be completed by November 1987.
(4018AWs/ van )
C.
Valve Testing To the extent practicable, each valve listed in Table I will be subjected to a test to verify that the valve successfully cycles when the differential pressure exists. The testing will be conducted using the respective systems in alignments which duplicate the configurations assumed for the design bases. Since the design differential pressures are typically selected based on very conservative assumptions, the maximum operating differential pressure was reviewed and selected for each valve. The maximum operating differential pressure is based on the justification provided in Table la.
In addition, in some cases it may not be possible to achieve the maximum operating differential pressure.
For those valves in Table I which may not be tested at the maximum operating differential pressure, additional justification for demonstrating the acceptability of the switch settings will be provided in the final report.
The completion schedule for the valve testing is provided in the attached MOV Program Schedule (Attachment 1).
D.
Control of Switch Settings The current control of MOV switch settings is via the use of generic procedures and the Limitorque Valve Operation Data Sheet. Although CP&L believes the existing controls have re.;ulted in adequate valve functions, a need for additional administrative controls is being evaluated. The evaluation and an implementation of the necessary procedures will be completed by November 1987.
E. & F.
Schedule and Final Report As noted in the cover letter, this submittal provides a response detailing the results of Bulletin action (a) and a program to accomplish Bulletin actions (b) through (d). provides CP&L's proposed schedule for the remaining items and a final report in accordance with the requirements of the Bulletin.
CP&L believes that the schedule submitted is realistic and practical. However, the action plan has several integrated tasks. The milestones shown on the attached schedule are planning targets and may be adjusted as required for completion. Completion of this effort is contingent upon the next refueling outage for which the schedule may change dependent on capacity factors and forced outages. Adjustments to the current plans may, therefore, be required; however, CP&L intends to complete the program within two years from the date of the Bulletin. Should major changes arise, we will inform you as necessary.
(4018AWs/vaw)
.o j
TABLE 1 DESIGN DATA FOR IEB 85-03 SUBJECT MOVs JUSTIFICATION CP&L VALVE VALVE FSAR DESIGN A P (psid)
MAX OPERATING A P (psid)
FOR MAX OPERATitEA P
ID NO FtMCTION FIGURE NO OPEN/CLOSE OPEN/CLOSE OPEN/CLOSE SI 870 A&B BIT Outlet 6.3.2-1 2750M) 1516/0 1/2 Isolation (See Justification provided in Table la)
AFW-V2-16A, B&C Motor Driven 10.1.0-5 1525/1525 1460/1378 3/4 AFW Pump-Dis-(54.4 Justif ication charge Isolation provided in Table Ia) i I
i i
AFW-V2-14A, B&C Steam Driven 10.1.0-5 1525/1525 1522/1420 5/6 AFW Pump-Ols-(See Justification charge isolation provided in Table la) i i
MS-VI-8A, R&C Steam Driven 10.1.0-1 1440/1440 1175/1175 7/8 AFW Pump-Steam (See Justification Admitting Valve provided in Table la) l i
(4018 TABLES /af)
l t
JUSTIFICATION FOR DETERMINATION OF MAXIMUM i
OPERATING DIFF' RENTIAL PRESSURE d
i i
TABLE la The expected maximum differential pressures for the opening and closing of valves during both normal and abnormal events were reviewed. Determination of the maximum differential pressure across the sub}ect MOVs included the review of: (1) the valves' operation during the initial demand to open or close (during ESF actuation), (2) the demand for the valves to open while performing the surveillance test (pump testing on miniflow), and (3) single inadvertent valve actuation during an event. As justification for 2;
the maximum operating differential pressures listed on Table 1, the realistic maximum differential pressure the valves are expected to operate against are provided below.
1.
The valves are required to open during the high pressure Si mode. Although the j
4 sequence (during ESF actuation) is such that the valve will start to open prior to pump start, the differential pressure during pump miniflow testing while taking suction from the RWST was considered (1516 psic'). No gross back-leakage through the check valves was considered since multiple check valves (3) are available i
downstream of the SI-870s. In addition, a single inadvertent actuation of the valve will not hamper the system operability since the valves are installed in parallel configuration.
2.
The valves are normally closed when the pumps are not operating, therefore, no flow-no high differential pressure is developed.
3.
The valves are required to open during certain ESF actuations. The maximum l
differential pressure will be equal to the pump's developed head on miniflow while taking suction from the Condensate Storage Tank (CST)(1460 psid).
t 4.
The valves are required to close (isolate) during a steamline break, a feedline break, or a steam generator tube rupture event, in order to isolate the faulted / ruptured steam generator. The maximurn differential pressure (1378 psid) will be equal to the p(ump discharge head while suction is being taken from the i
alternate water supply deep well pumps).
5.
The valves are required to open during certain ESF actuations. The maximum differential pressure will be equal to the pump's developed head on miniflow while l
taking suction from the CST (1522 psid).
6.
The valves are required to close (isolate) dur'ng a steamline break, a feedline break, or a steam generator tube rupture event, in order to isolate the faulted / ruptured steam generator. The maximum differential pressure (1420 psid) will be equal to the p(ump discharge head while suction is being taken from the alternate v/ater supply deep well pumps).
l 7.
The valves are required to open during certain ESF actuations. The highest steam l
generator safety valve set point pressure plus 3 percent accumulation was l
considered for the maximum differential pressure (1175 psid).
8.
The valves are required to close (isolate) the steam feed from the faulted / ruptured steam generator. The highest steam generator safety valve set point pressure plus 3 percent accumulation was considered for the maximum differential pressure (1175 psid).
noisAws/ve.)
~
TA8ti 2 IWVs DELLEED FIEBf TK BILifTIN CPAL VALVE VALVE FSAR ID NO.
FtMCTION FIGURE No.
JUSTIFICATIONS SI-864A&8 St Pump 6.3.2-1 These MOVs are placed in the normally open position. Their function is to close to Suction isolate the RWST from the discharge of the fHt pump durlog the long-tere recirculation from RWST mode of operation. Therefore, the valves are not required to function under the high pressure Si mode, in addition, during conditions of operation with reactor coolant pressure in excess of 1000 psig, the AC control power is removed from the MOVs in the open position (TS 3.3.1.1(g)).
SI-878A&8 S1 Pump-6.3.2-1 These MOVs are placed in the normally open position. Operation of these valves is Discharge not mentioned in the Emergency Operating Procedure during the high pressure injection Cross-Connect mode. Therefore, the valves are not required to function under the high pressure SI mode.
In addition, during conditions of operation with reactor coolant pressure In excess of 1000 psig, the AC control power is removed f rom the MOV in the open position (TS 3.3.1.1(g)).
$1-869 St Pump-6.3.2-1 This MOV is placed in the normally open position. Their function is to allow Discharge to realignment of the $1 system during the long-term recirculation phase of ECCS operation.
l RCS Hot Leg Therefore, the valve is not required to function under the high pressure $1 mode, injection St-866A&8 St Pump-6.3.2-2 These MOVs are placed in the normally closed position. Their function is to allow Discharge to realignment of the Si system during the Ics.g term recirculation phase of ECCS RCS Hot Leg Operation. Therefore, the valves are nee required to function under the high j
injection pressure Si mode.
SI-867A&8 BIT Inlet 6.3.2-1 These MOVs are placed in the normally open position. Since CP&L requested the renovel of Isolation the TS requirements for a highly borated water supply in the BIT, the valves function to maintain and Isolate the high boron concentration within the 81T is no longer required.
Therefore, the valves are pieced in an open position and are not required to function under the high pressure $1 mode, in addition, a single inadvertent actuation of the valve will not hamper the system operability since the valves are Installed in parallel conkiguration.
AFW-V2-20A&B Motor Driven 10.1.0-5 These MOVs are placed in the normally open position. The motor driven AFW pump-j AFW Pump-discharge cross-connect valves do not receive an ESF signal. In addition, even with l
Discharge a single inadvertent operation of the valve, all three steam generators will Cross-Connect still be fed by the motor-driven AFW pumps.
91MTAfttt*
.*)
ATTADetter I IEB 85-03 IIDW PItostAst SOEDULE l
.g a
ma er nov e7
= se I
i l
I l-1 Action Plan a Estabilth IES Action Plan g Complete Action Plan a and set,mit sc d.i. for. t, d Action Plan b Establish lattlet correct sulich settings Rowlew and essess Isltlet (torque, torque bypass, position llett, solich settings based on Establish final seltch overload) test results settings C
O-A Action Plan c Velve Itofueling Testing C
O E..ie.t. a l
Verify Test Rosetts Complete Action Plan c l
Action Plan d lleview & essess control of seltch settlegs (torque, torque bypass, position llett, overload)
Complete Action Plan d 3
so o.,s Submit Final 3
Itapart 140leTattES/Weel