ML20056A510

Insp Repts 50-413/90-15 & 50-414/90-15 on 900527-0623. Violation Noted.One Noncited Violation Noted.Major Areas Inspected:Review of Plant Operations,Surveillance Observation & Maint Observation

ML20056A510
Person / Time
Site:	Catawba
Issue date:	07/19/1990
From:	Hopkins P, William Orders, John Zeiler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20056A508	List: ML20056A507 ML20056A509 ML20056A510
References
50-413-90-15, 50-414-90-15, NUDOCS 9008080079
Download: ML20056A510 (12)

See also: IR 05000413/1990015

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RJt! UNITED STATES .

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NUCLEAR REGULATORY COMMISSION

REGION il

g ,j 101 MARIETTA STREET.N.W.

• 's ATLANTA, G EORGI A 30323

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~ Report Nos. 50-413/90-15 and 50-414/90-15

Licensee: Duke Power Company

P.O. Box 1007

Charlotte, NC 28201-1007

Docket Nos.: 50-413 and 50-414 License Nos.: NPF-35 and NPF-52  ;

Facility Name: Catawba Units l'and 2

Inspection Conducted: May 27, 1990 - June 23, 1990

t Inspectors: W h L V % D Ly 7/l'l/1b

W. T. Orders, Senior Resfdent Inspector D6te' Signed

(#dt i v Q h m in  ?/M/93

P. C. Hopkins, Resident Inspector Date Signed

LJAtu W?W Im 1h9/No

J. Zei r, Res ent I ctor D'ats Signed .:

' Approved by:

M.- B( Shyml_ock, Chief /

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Date Signed' .,

Projects Section 3A / 9

Division of Reactor Projects

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SUMMARY j

Scope: This routine, resident inspection was conducted on site inspecting in

the areas of. review of plant operations; surveillance observation;

and maintenance observation.

Results: One violation was . identified involving the incorrect installation of

solenoid valves on the Unit 2 high" pressure carbon dioxide fire

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' protection system. Inadequate pre-operational testing and routine

operating' surveillance failed to identify the error which resulted in -

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this Technical' Specification required system being inoperable since

commercial operation. (Paragraph 4.c)

One

failurenon-cited

to follow violation

shutdown(NCV) was identified

procedures. involving)an

(Paragraph 2.d operator's

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9008080079 900720

PDR ADOCK 05000413

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REPORT DETAILS

'1. Persons Contacted

, Licensee Employees

• M. Brady, Assistant Operating Engineer

B. Caldwell, Station Services Superintendent

R. Casler, Operations Superintendent

T. Crawford, Integrated Scheduling Superintendent

J. Ferguson, Shift Operations Manager

• J. Forbes, Technical Services Superintendent

R. Glover, Performance Manager 2

T. Harrall, Design Engineering

• L. Hartzell, Design Engineering

R. Jones, Maintenance Engineering Services Engineer

V. King, Compliance

F. Mack, Project Services Manager

W. McCollum, Maintenance Superintendent

• T. Owen, Station Manager.

Other licensee employees contacted included technicians, operators,

. mechanics, security force members, and office personnel. 1

NRC Resident Inspectors

• W. Orders

P. Hopkins

• J. Zeiler.

Other NRC Personnel

• T. Cooper, Resident Inspector, McGuire Nuclear Station- ,

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• Attended exit interview.

.2. Plant Operations-Review (71707 and 71710)

a. The inspectors reviewed plant operations throughout the reporting

period to' verify conformance with regulatory requirements, Technical

Specifications (TSs), and administrative controls. Control Room

logs, the Technical Specification Action Item Log, and the removal

and restoration log were routinely reviewed. Shift turnovers were

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observed to verify that they were conducted in accordance with ,

approved procedures. Daily plant status' meetings were routinely I

attended.

The inspectors verified by observation and interv,iews~, that the

measures taken to assure physical protection of the facility met

current requirements. Areas inspected included the security

organization, the establishment and maintenance of gates, doors, and )

isolation zones in the-proper conditions, and that access' control and ,

badging were proper and procedures followed;

I In addition.to the areas discussed above, the areas' toured were

observed for fire prevention and protection activities and a

radiological control practices. The inspector reviewed Problem-

Investigation Reports to determine if the licensee was appropriately

documenting problems and implementing corrective actions,

b. _ Unit 1 Sumary

Unit 1 began the report period in Mode 1, operating at virtually full

power. .On June 7, the unit began a shutdown for a forced outage due

to the inability to repair the 1B Nuclear Service Water (RN) Pump j

within the time allowed by the applicable technical specification.

The RN pump had been removed from service on June 5 because of high

motor vibration. -The licensee had p1anned.to rep 1 ace-the pump motor

with a spare that was being rebuilt, but due to complications in-

repairing the spare, they were unable:to complete-their efforts

.within the time allowed. The licensee then decided to remove the

motor from the ~ Unit 2 2A RN Pump and install it on the 1B RN Pump.

Maintenance activities to swap the motors began on June-10 after Unit-

2 entered Mode 4.

u At 6:00 a.m. on June 11, the licensee reported that an operator error  !

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involving a failure to follow procedure resulted in the-inadvertent l

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transfer of approximately 5,000 gallons of water from the Reactor

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Coolant (NC) System to the Refueling Water Storage Tank (RWST). .A

l control room operator, while performing a routine surveillance test,  !

failed to confirm that a valve in the Residual Heat Removal (ND)

return line to the RWST was closed before opening a series of ND

l; isolation valves which created a flowpath from the NC system to the

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RWST. Operators were responsive to the transient which ensued and-

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quickly isolated the flowpath erroneously created. Details

pertaining to.this event are described in NRC Inspection Report Nos.50-41s,414/90-17. '

By June 14, the licensee had completed maintenance activities to

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restore the IB RN Pump to operable condition. The unit entered Mode

4 on June 15, and Mode 3 on June 17. The inspectors witnessed

criticality onLJune 19 and the unit. entered Mode 1 that same day. At

the end of the report period Unit I was at 100 percent power

operation. 1

c, . Unit 2 Sunnary  !

Unit 2 started the report period in Mode 2, 97 percent power.

BeginningLon June 2, power was slowly reduced in preparation for the. ,

E0C-3 refueling outage. On June 8, the unit commenced shutdown for

the. refueling outage, entering Mode 3 on June 9. On June 10, during

cooldown and depressurization to Mode 4,-a feedwater isolation

occurred during the performance of a manual reactor trip functional

test. The feedwater isolation signal was immediately reset and

feedwater flow re-established. Details concerning this event can be-

found in paragraph.3.c. The unit entered Mode 6 on June 22.

d. ' During the Unit 1 cooldown and depressurization from Mode 3 to Mode 5

on June 8, 1990, a control room operator performing Enclosure 4.2 of'

OP/1/A/6100/02, Unit Shutdown from Mode 3 to Mode 5, failed to block.

the. Low Steam.Line and Low Pressurizer Pressure Safety Injection (SI)-

signals'before allowing Main Steam pressure to decrease below 875 . t

psig, the administrative limit specified by the procedure.. The' unit.

-was at approximately 1960 psig NC pressure and 830 psig' steam

pressure when the shift supervisor, who was monitoring the cooldown,

? noticed the . steam pressure and had the operator block the sis The-

cooldown continued without further-incident.. t

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The' inspectors reviewed the applicable portions of the procedure.

Two cautions in Steps 2.15 and 2.19, performed before and during NC

cooldown,-clearly state the Low Steam Pressure SI'shall be blocked

before pressure decreases below 875 psig. A Low Steam Dressure SI

l occurs at 725 psig, but is rate sensitive. The-inspectors were

! informed that the cauticns and administrative limit of 875 were added

to the procedure after an inadvertent SI occurred on rate compensated

low steam pressure during a Unit 2 cooldown on February 21, 1989.

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This-licensee identified violation is not being cited because the I

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criteria specified in-Section V.G.1 of the NRC Enforcement Policy

were satisfied. Accordingly, this is documented as a licensee

identified Non-Cited Violation, NCV 413/90-15-01: Operator Failure

to Follow Shutdown Procedure,

g 3. Surveillance Observation (61726)

a. During the inspection period, the inspectors verified plant

-operations were in compliance with various Technical Specification

requirements. Typical of these requirements were confirmation of. ,

compliance with the Technical Specifications for reactor coolant

chemistry, refueling water tank, emergency power systems, safety

injection, emergency safeguards systems, control roorn ventilation,

.and direct current electrical power sources. The inspectors verified

that surveillance testing was performed in accordance with the

approved written procedures, test instrumentation was calibrated,

limiting conditions for operation were met, appropriate removal and

restoration of the affected equip. ment was accomplished, test results

met = acceptance criteria and were reviewed by personnel other than the !

individual directing the test, and that any deficiencies _ identified

during the testing were properly reviewed and resolved by appropriate

management personnel.

b.. The inspectors witnessed or reviewed aspects of the following '

surveillances:

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IP/2/A/3200/03 Reactor Protection / Safeguards Features

Response Time Testing

IP/0/A/3240/04A Unit 2'18-flonth Nuclear Instrumentation

System Source Range Channel Calibration

PT/1/B/4250/04A Feedwater Pump Turbine Weekly Test

.PT/1/A/4250/04B Feedwater Pump Turbine Stop Valve Movement-

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Test

PT/1/A/4150/01D NC System Leakage Calculation

PT/1/B/4250/05 Generator Core Monitor Monthly Test

PT/1/A/4600/02A- Mode 1 Periodic Surveillance Items

PT/1/A/4200/06A Boron Injection Valve, Lineup Verification

PT/1/B/4150/23 Ventilation Unit Condensate Drain Tank  ;

Increase' Test

PT/1/A/4200/09A Auxiliary Safeguards Test Cabinet Test

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c. Feedwater Isolation During Reactor Trip Breaker Testing

On June 10, 1990, a Main Feedwater (CF) isolation occurred on-Unit 2

while' operators were performing procedure PT/2/A/4600/15; Manua11

Reactor Trip Functional Test. The CF system isolation signal was  !

generated when Reactor Trip Breaker (RTB) 2B was cycled while it'was

in the " test" position. Unit 2 was in Mode 3, with the NC system

Tavg-at approximately 450*F. The CF isolation signal caused the CF

valves to close, isolating flow to the Steam Generators. Operations

personnel responded immediately by resetting the signal, opening the j

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valves to restore flow, stabilized the unit and continued with'the

cooldown and depressurization,

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Troubleshooting revealed that the breaker's auxiliary switch  ;

contacts, which block the feedwater isolation signal during breaker

testing, had bounced open and then reclosed when the breaker was

cycled. This'had in turn caused the isolation to become momentarily

unblocked, resulting in the transient. Ultimately, it was determined

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that the breaker was not completely aligned in the " test" position,

causing-the problem.

Further breaker' testing is planned and the functional test procedure

is to be reviewed by the licensee to determine if changes are

necessary based on the problems encountered with the-breaker

positioning. The inspectors will follow this problem to its

conclusion. '.This is identified as -Inspector Followup Item (IFI) -

414/90-15-02:. Review of Licensee Investigation'of CF lsolation I

During Testing of RTBs. :i

d. Diesel Generator Invalid Failures

Since April 1990, the licensee has experienced three start failures.

(considered as " invalid," for purposes of test frequency adjustment -:

and r2 portability) on Unit 2 Diesel Generators (DGs) 2A and-2B'due to  !

reverse power relay actuations. The first invalid failure occurred ,

on April 18,.1990, during the monthly operability performance; test

-for DG 2B. The output breaker tripped on reverse power while the

operator was attempting to synchronize the DG with the 4160 Volt

Essential Power Bus (2ETB). The licensee attributed the trip to the. ,

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operator's. failure to adjust the output voltage high enough above~the

line voltage to prevent actuation of the reverse power relay. .The

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basis for this determination was that no equipment malfunction could'

-be identified after troubleshooting of the components in the system.

Prior to this failure, there had been no cases recorded of an-

operator error causing a reverse power trip while performing the.-

paralleling evolution.

The.second invalid failure occurred on May 21 during the monthly.

operability test of DG 2A. Again, the failure occurred as a result-

of a reverse power trip durQg the paralleling evolution. The

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licensee _ reported that the operator involved may have depressed the

' voltage control" raise aushbutton instead of the " speed increase"

pushbutton. This would lave caused the power factor to be reduced 3

which could have caused a reverse power trip. The operator also

p stated that line voltage may have been higher than DG output voltage

' when the breaker was closed', which would have also tripped the DG on- '

. reverse power. - Following the failure, it was verified that the

voltage meter that the operator was observing was within calibration.

The licensee plans to check the- reverse power relay during the-

current Unit 2 refueling outage in order to verify _ it is operating' .,

properly. Based on discussions with the operator and the lack of 1

evidence,of equipment malfunction, the licensee concluded that.this

trip was also caused by operator error.

On June 12 another invalid failure occurred on DG 2B following the

24-hour operability-run required by technical specifications.- The DG

had just completed the 24-hour run and was being used to maintain the

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-loads on 2ETB switchgear while it's. normal' source of power was being

swapped to-it's alternate supply. When the DG was; paralleled to 2ETB

at the beginning of the 24-hour run, no problems were encountered.

Before closing the breaker;to the alternate powsr supply, it was-

verified that voltage indication at the local control panel in the DG j

room agreed,with indicatio'n in the Control Room. ~However, when the

breaker was closed, it tripped on' reverse power. The licensee  ;

determined that, in this instance, no error on the part of the

operator caused the reverse power trip.

The licensee reported that DGs 2A and 2B were both available during

the trips on reverse power since the reverse- power relay trip and -

associated synchronizing circuitry are bypassed on an emergency  ;

start (the rationale for considering the above to be invalid test  ;

failures). During an emergency start the essential bus is shed, and

then the DG breaker is closed and' the essential loads are sequenced

) onto the bus.

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The June 12 invalid start failure on DG 2B indicated that the-root

cause'of the recent failures may not be solely crerator error. .A

special testing program is being developed to investigate more

thoroughly the com

-the root cause(s)ofponents

the trips.involved in the synchronizing

The inspectors circuitry and

will- follow the

licensee's investigation of the DG problem. This is identified-as

IFI 414/90-15-03: Review of Licensee Investigation of Reverse Power

Trips on DGs 2A and 2B.

No violations or deviations were identified.

4. MaintenanceObservations-(62703)

a. Station maintenance activities of selected systems and components

were observed / reviewed to ascertain that they were conducted in

accordance with the requirements. The inspectors verified licensee

conformance to the requirements in the following areas of inspection:

the activities were accomplished using approved procedures, and

functional testing and/or calibrations were performed prior to

returning components or systems to service; quality control records-

were maintained; activities performed were-accomplished by qualified

personnel; and materials used were properly certified. Work requests

were reviewed to determine status of outstanding jobs and to assure

that priority was assigned to safety-related equipment maintenance

which may effect system performance.

'b. Maintenance activities witnessed or reviewed by the inspectors

included but were not limited to the following:

0169TRD Nuclear Service Water Spare Motor 1B Refurbishment

c. Review of Maintenance on the Hign Pressure Carbon Dioxide. Fire

Protection System

On April 21,1990, Unit 2 was in Mode 1, Power Operation, when at

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2:30 p.m. the high pressure carbon dioxide (C02)' fire protection

system discharged in the Auxiliary Feedwater (CA) System area. The

CO2 discharge occurred as a result of an unexpected steam release in

the turbine driven pump pit during maintenance to clean out' clogged

drain lines. The turbine driven pump pit C02 discharge header had

been manually isolated as a precautisney hasuih but tha system

erroneously discharged into born motor driven pump pits. The system

is designed i,u dischstge into only the pit _with a fire hazard. .

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During investigation, the solenoids on.the three pilot valves which

serve to select the-system's discharge path were.found to be

-installed backwards. This had caused all.three pit-selector valves

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to open instead of just the one for the turbine driven pump room.

_The investigation also revealed that the solenoids had apparently

been installed backwards during construction, and neither

pre-operational testing nor routine surveillance had detected the ,

error.

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Background R

The high pressure 002 system, as it is referred to_in Technical ,

Specification 3.7.10.3, provides fire protection f0r the CA System

Pump-pits. Three selector valves are provided in. the CO2 discharge

header which, individually, receive an actuation signal associated

with the pit that is to receive the CO2 discharge.

The three selector valves, one for each pit, are pilot-actuated by .  ;

C02 pressure from the C0: cylinder discharge header. Three pilot and'  ?

solenoid valve assemblies: isolate the C02 pressure from its 1

associated selector valve until a fire: hazard signal is received from

a pit. Once a signal is received, the solenoid and pilot open, .

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allowing C02 pressure to the top chamber of the selector valve, which

then opens to discharge to the_ appropriate pit'. The solenoid valves

are two-way, normally closed, soft seat valves..

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_ Event Description i

As-previously. stated, on April 21,.1990, operations personne1'were  ;

- attempting to pressurize the Unit'2 Auxiliary Steam (SA) supply line ,

to the.CA Pump Turbine in order to clean out debris that was

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suspected to have accumulated in the SA_line drains. When the SA  ;

L line was pressurized, steam escaped into the turbine driven CA, pump  !

pit and resulted in an inadvertent actuation of the CA pump pit CO2

fire protection' system. The CO2 system,'previously isolated to the

turbine driven CA pump, erroneously discharged to both motor driven +

CA pump pits. After the room was ventilated, a continuous fire watch

was established, as required by Technical Specification 3.7.10.3.

H This~ fire watch remained until the system was declared operable on

May 17.

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On the following day, during troubleshooting, it was confirmed that- j

all three selector valves received pilot pressure for actuation. On i

April 23, Design Engineering was requested to assist in determining 1

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the cause of the simultaneous actuation. .On April 24, it was

confirmed- that all solenoids were receiving the correct electrical

signals. indicating that no problems existed in the electrical t

circuitry. - On April 26, nitrogen was used > to pressure test the

' actuation portion _of the system. It_was observed that nitrogen _was

~escap_ing from the exhaust vent in the pilot pressure port ~ of the

supposedly closed pilot valves. A work request was initiated to

investigate the failure of the pilot and solenoid valves.  ;

%' On April'30, review of the applicable assembly drawing by the-

licensee' revealed that-the solenoids were-installed backwards on the

pilot valves. All three solenoids were reversed and the assemblies

were reinstalled into the-system. On May 3, 1990, Maintenance

EngineeringServices(MES)initiatedProblemInvestigationReport

(PIR)-2-C90-0156 to evaluate past operability of the system. MES .

L review indicated that no work had been performed on the- *

pilot / solenoid valve. assemblies since ' initial installation, which

ruled out the possibility that the solenoids had been reversed during

maintenance. On May 15 Design Engineering concluded that the

required design concentration could not be achieved with a CO2

discharge into more than one- CA pump pit and that the4 system had been

inoperable when-the pilot valve solenoids were installed backwards.

Refilling of depleted C0 cylinders and repairs to system leaks

discovered during testing were complete-on May 17. The system was

returned to service at 4:00 p.m. tlat afternoon. .

The licensee reported this event in LER 414/90-08.

Conclusion

The pi. luc / solenoid assemblies were installed backwards on Unit 2 i

during construction. Pre-operational testing of the system was

inadequate in that the tests did not confirm that the system was

capable of performing it's intended safety function.

The testing performed to fulfill the requirements of Technical' i

Specification surveillance 4.7.10.3.3.b(1) was inadequate. The

surveillance requires that at least once per 18 months it be verified  ;

that "... each system actuates manually and automatically.upon

receipt of a simulated actuation signal". The surveillance being

performed only confirmed that the solenoids changed position, but did

not confirm that the system would actuate as designed. ,

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Therefore, the 00r system was incapable of suppressing a fire in'.the

auxiliary feedwater pump pit areas.for Unit 2. ,

" T Results.

10 CFR 50,' Appendix B, Criterion XI; Test Control; requires that a

test program be established to assure that'all testing required to -r

demonstrate that structures, systems, and components will perform

satisfactorily in service is identified and performed .in accordance

with written test procedures. The test program shall; include, as

-appropriate, proof tests prior to installation, pre-operational

tests,' and opuational tests during nuclear power. plant operation, of

structures, systems, and components.

Technical Specification 3.7.10.3(b)-requires that the high pressure' "

CO2 fire protection system be operable whenever the equipment

protected by the system is required to be operable. .The protected

equipment consists of the auxiliary feedwater pump rooms. Auxiliary

Feedwater is required to be operable in Modes 1, 2, and 3. Technical

Specification 4.7.10.3.3.b(1) also requires that the high pressure

C0 system be demonstrated operable at least once per 18 months by

verifying that the system actuates manually and automatically upon

receipt of a simulated actuation signal'.

The solenoids on the three pilot valves associated with the Catawba

Unit- 2, high pressure C02 fire protection system were : installed

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- backwards during construction. -Subsequent pre-operational testing of ;

i theLsystem failed to identify the error which prevented the .

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1- components / system from operating satisfactorily in service. Further,

routine surveillance conducted during operation has been. inadequate

in that it hasinot demonstrated that the system was operable (nor

detected the inoperability) by verifying system actuation either

i manually or automatically upon the receipt of a' simulated actuation *

l signal. This is identified as Violation 50-413/90-19-04: Failure to

L Meet Technical Specification Requirements for High Pressure CO2

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System Operability.

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5. Exit Interview

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The inspection scope and findings were summarized on June 26, 1990, with '

those persons indicated in paragraph 1. The inspector described the areas

inspected and discussed in detail the inspection findings listed below.

No-dissenting comments were received from the licensee. The licensee did

not identify as proprietary any of the materials provided to or reviewed

by the inspettors during this inspection.

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Item Number Description and Reference-

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NCVJ413/90-15-01 Operator Failure 1to Follow Shutdown Procedure.

(Paragraph 2.d) i

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IFI 414/90-15-02- Review of Licensee Investigation of CF lsolation-

During Testing of RTBs . (Paragraph-3.c).

IFI 414/90-15-03

Review of Licensee

on DGs 2AInvestigation of Reverse.

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Power Trips and 2B. (Paragraph _;

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VIO 413/90-15-04 Failure to Meet Technical. Specification

Requirements for High Pressure 00: System

Operability. (Pa'ragraph 4.c)_

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