ML17306A375

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Insp Repts 50-528/91-40,50-529/91-40 & 50-530/91-40 on 911013-1114.Violations Noted.Major Areas Inspected: Previously Identified Items,Review of Plant Activities, ESF Sys Walkdowns & Surveillance Testing
ML17306A375
Person / Time
Site: Palo Verde  Arizona Public Service icon.png
Issue date: 12/18/1991
From: Koltay P
NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
To:
Shared Package
ML17306A373 List:
References
50-528-91-40, 50-529-91-40, 50-530-91-40, NUDOCS 9201070117
Download: ML17306A375 (44)


See also: IR 05000528/1991040

Text

U. S.

NUCLEAR REGULATORY COMMISSION

RE

ION

V

Re ort Nos.

Docket

Nos.

License

Nos.

Licensee

50-528/91-40,

50-529/91-40,,

and 50-530/91-40

50-528,

50-529,

and 50-530

NPF-41,

NPF-51,

and

NPF-74

Arizona Public Service

Company

P. 0.

Box 53999,

Station, 9012

Phoenix,

AZ 85072-3999

Faci lit

Name

Palo Verde Nuclear Generating Station

Units 1, 2,

and

3

x

Ins ection Conducted

October

13 through

November

14,

1991

Ins ectors

D. Coe,

F. Ringwald,

J. Sloan,

M. Young,

B. Ang,

D. Acker,

Senior Resident

Inspector

Resident

Inspector

Resident

Inspector

Resident

Inspector

Project Inspector,

Region

V

Inspect'or,

Region

V

o tay,

ie

Reactor Projects

Section II

a

e

igne

Ins ection

Summar

Ins ection

on October

13 throu

h November

14

1991

Re ort Numbers

50-528/9 -40

50-529/9 -40

and 50-530

9 - 0

Areas

Ins ected'

Routine, onsite,

regular

and backshift inspection

by the

t ree ress

ent inspectors,

and two inspectors

from the Region

V staff.

Areas

inspected

included: previously identified items; review of plant activities;

engineered

safety feature

system walkdowns - Units 1, 2,

and 3; surveillance

testing - Units 1, 2,

and 3; plant maintenance

- Units 1, 2,

and 3;

simultaneous

reactor trips - Units

1 and 3; cracked battery cell - Unit 1;

Unit 3 restart;

auxiliary feedwater

equalizing valve found open - Unit 3;

program enhancements

for loss of decay heat

removal - Units. 1, 2,

and 3;

refueling activities - Unit 2;

and review of licensee

event reports - Units 1,

2,

and 3.

During this inspection

the following Inspection

Procedures

were utilized:

60705,. 60710,

61726,

62703,

62704,

71707,

71710,

92700,

92701,

92702,

and 93702.

Results

Of the

10 areas

inspected,

>wo

cited violations were identified.

A Un>t

2 violation pertains

to two examples of failure to follow Radiation

t

Exposure

Permit requirements

(Paragraph 3.D.(ii)).

A Unit 3 violation

pertains to failure to follow procedures

(Paragraph

9).

920i070ii7 9ii2i8

PDR

ADQCK 05000528

8

PDR

1

tI

-2-

General

Conclusions

and Specific Findin

s

Significant Safet

Matters

None

Summar

cf Violations

2 Cited Violations

Summar

of Oeviations

0 en Items

Summar

None

2 items closed,

2 items left open,

and

4

nevi items opened.

Stren ths Noted

The analysis of the turbine control circuit response

resulting in the dual

Unit I and

3 trips was thorough.

Meaknesses

Noted

I

Several

examples

are noted in which personnel

exhibited

a relaxation in

standards

of control over activities

and

adherence

to procedures.

These

were

seen

in the areas

of 'core alterations,

radiological practices,

and compliance

with

a re'actor startup

procedure.

0

'f

I

DETAILS

1.

Persons

Contacted

The below listed technical

and supervisory

personnel

were

among those

contacted:

Arizona Public Service

(APS

'*R. Adney,

  • J. Albers,

J.

N. Bailey,

B. Ballard,

D. Blackson,

T. Bradish,

R. Cherba,

  • J. Fisher,
  • R. Flood,

J. Fooarty,

D. Fuller,

R. Fullmer,

  • R. Fountain,
  • D. Gouge,
  • S. Gross,
  • S. Guthrie,
  • W. Ide,
  • A. Johnson,

'. Levine,

D. Mauldin,

J. Minnicks,

  • G. Overbeck,

R. Prabhakar,

, *M. Radoccia,

  • R. Rouse,

C. Russo,

R. Schaller,

T. Schriver,

J. Scott,

J. Scott,

  • M. Shea,

R. Stevens,

Plant Manager,

Unit 3

Manager,

Radiation Protection

Operations

Vice President,

Nuclear Safety

8 Licensing

(NSEL)

Special Assistant to Executive

V P:

Manager,

Central

Maintenance

Manager,

Compliance

Manager, Quality Systems

Manager, Civil, (acting Dir.) Nuclear Engineering

Dept.

Plant Manager,

Unit 2

Manager,

Work Control Unit 2

Manager,

Chemistry Unit

1

Manager,

Quality Audits and Monitoring

Supervisor,

Quality Assurance

and Maintenance

Manager,

Plant Support

and

(Chairman Plant Review Bd.)

Engineer,

El Paso Electric

Site Director, Quality Assurance

(QA)

Plant Manager,

Unit

1

Supervisor,

Compliance

Vice President,

Nuclear

Power Production

Manager,'ite

Maintenance

Manager,

Maintenance

Unit 3

Site Director, Technical

Support

(STS)

Manager, Quality Engineering

Manager,

Site Nuclear Engineering

Dept.

(SNED)

Supervisor,

Compliance

Manager, Quality Control

(QA/QC)

Assistant Plant Manager,

Unit

1

Assistant Plant Manager,

Unit 2

Assistant Plant Manager,

Unit 3

General

Manaoer,

Chemistry

Manager,

Radiation Protection

Director, Licensing

E Compliance

SITE REPRESENTATIVES

  • J. Draper,

Site Representative,

Southern California Edison

  • R. Henry,

Site Representative,

Salt River Project

The inspectors

also talked with other licensee

and contractor

personnel

during the course of the inspection.

  • Personnel

in attendance

at the exit meeting held with the

NRC Resident

Inspectors

on November

14,

1991.

2.

Previousl

Identified Items - Units

1

2

and

3 (92701

and 92702)

A

A.

Unit i

None this report.

B.

Unit 2

C.

None this report.

Unit 3

Closed

Fol lowup Item

530/91-29-05:

"Undervol ta

e Condition

-- on

ass

E Bus

PBA-S

3 - Unit 3"

9

0

This item involved evaluation of the Root Cause

of. Failure

(RCF)

and safety sionificance of an incorrectly set voltage tap

on the

Engineered

Safety Features

(ESF) Service Transformer supplying 4160

volt ESF

bus

PBA-S03.

The inspector

reviewed Condition

Report/Disposition

Request

(CRDR) 3-1-0086,

which documents

the

licensee's

evaluation.

The

CRDR determined that the tap 'had most likely been improperly

positioned

in April 1991 during the Unit 3 refueling outaoe

following testing of the turns-to-turns ratio for each tap setting.

Work Order

(WO) 462655 indicates

the tap was properly set at

position three,

but

no other work activity was identified in which

the position could have

been

changed

since then,

and

such

an

activity would not likely have

gone unnoticed while the transformer

was energized.

The licensee initiated Instruction

Change

Request

( ICR) 24701 to procedure

32MT-9ZZ83,

by which the testing

was done,

to include

a step for independent

verification of the as-found

and

as-left tap positions.

In evaluating

the safety significance of the improperly set voltage

tap, the licensee

determined that there wasno nuclear safety

concern

as

a result of this occurrence

because

the undervoltage

condition was

sensed

by the protective relays

as designed.

This condition is bounded

by the safety analysis.

Based

on this

review, this item is closed.

No violations of

NRC requirements

or deviations

were identified.

3.

Review of Plant Activities

71707

and

93702

A.

Unit 1

Unit

1 entered

the reporting period at 100 percent

power.

On

October

27,

1991,

at 7:21

AN (MST), Units

1

and

3 tripped

simultaneously after experiencing turbine load osci llations (see

Paraoraph

7).

A Notice 'of Unusual

Event

was declared

because

a

safety injection

and containment isolation also occurred during the

event.

Both Units were stabilized in Mode 3.

Unit 1 was restarted

on October

31,

1991.

Power

was increased

to lOOX on November 2,

1991,

where it was maintained for the duration of the reporting

period.

Unit 2

Unit

2 entered this 'reporting period at

100 percent

power.

Power

was reduced

and the reactor

was taken off line on October

17,

1991, for

a scheduled

70 day refueling outage.

Prior to the

shutdown

on October

14,

1991,

high temperature

alarms

were

experienced

on the unit auxiliary transformer.

Operators

shifted

in-house

loads to the startup transformers

where they remained

until shutdown.

Cooldown to Mode

5 was -completed

on October

17,

1991.

Mode

6 was entered

on October

23,

1991,

and the core offload

was completed

on November

2, 1991.

The unit remained

in this

defueled

Mode for the duration of the reporting period.

Unit 3

Unit 3 entered this reporting period at

100 percent

power.

On

October 27; 1991,

at 7:21

AM (MST), Units

1

and

3 tripped

simultaneously after experiencing turbine load osci llations

(see

Paragraph

7).

Unit 3 first experienced

a reactor

power cutback.

A

Notice of Unusual

Event

was declared

because

a safety injection

and

containment isolation also occurred during the event.

Both Units

were stabilized in Mode 3.

A reactor startup

was

commenced

on

October

28,

1991,

but was terminated to address

questions raised'y

the

NRC Resident

Inspectors

regarding

whether plant conditions

were

consistent

with the applicable

bounding safety analysis.

Following

the resolution of these

items, Unit 3 was restarted

on October 30,

1991

(see

Paragraph

12).

Power

was increased

to 100 percent

on

November

1, 1991,

where -it was maintained for the duration of the

reporting period.

Plant Tours

The following plant

areas

at Units 1, 2,

and

3 were toured

by the

inspector during the inspection:

o

Auxiliary Building

o

Control

Complex Building

o

Diesel Generator

Building

o

Fuel Building

o

Main Steam Support Structure

o

Radwaste

Building

o

Technical

Support Center

o

Tur bine Bui lding

o

Yard Area

and Perimeter

(

O.

x

L

The following areas

were observed

during the tours:

0 eratinq

Lo'

and Records - Records

were reviewed .against

ec naca

peel

scatsons

and administrative control procedure

requirements.

(2)

(4)

(5)

Durino

a walkdown of the Unit 2 instrument air system with the

responsible

system

and nuclear engineers,

the systems

enoineer

found that the dryer towers

were not performing

as expected.

The operating train of dryer towers

(two towers per train) are

designated

to swap the drying function every five minutes

allowing the dormant tower to discharge

the moisture

accumulated

during the previous five-minute cycle.

However,

contrary to the design,

the towers were being manually

and

locally swapped

by the operations

personnel

every six hours or

when the high moisture

alarm indicated in the Control

Room.

This condition

had existed for three days,

however the

operations staff had not referred the problem to the

appropriate site technical

support

group.

The potential

exists,

in this configuration, for excessive

moisture in the

system to exceed

the moisture

removal capability of the

instrument air system.

Because

the second train of dryers

was

unavailable

excessive

moisture in the affected train could

degrade

the instrument air system.

The instrument air system

is not safety related,

but serves

main feedwater

and other

. secondary plant valves,

as well,

as

letdown

and charging

system valves.

The systems

engineer

responded

to the finding expeditiously,

contacting the appropriate

level of supervision

in his

own

management

as well as in the operations

and work control

departments.

The second train was subsequently

restored to

service.

Licensee

review of this matter will be documented

on

Condition Report/Disposition

Request

(CRDR)

Number 2-1-190.

Monitorin

Instrumentation - Process

instruments

were observed

for corre ation

etween

c annels

and for conformance

with

Technical Specification requirements.

~She<<S<<i

.C

1

i<< <<iq

for conformance with 10 CFR Part 50.54.(k), Technical

Specifications,

and administrative procedures.

E ui ment Lineu

s - Various valves

and electrical

breakers

were verified to be in the position or condition required

by

Technical Specifications

and administrative

procedures for the

applicable plant mode.

E ui ment

Ta oin

- Selected

equipment, for which tagging

requests

a

een initiated,

was observed

to verify that tags

were in place

and the equipment

was

in=-the condition

specified.

(6)

General

Plant

E ui ment Conditions - Plant equipment

was

observed for indications of system

leakage,

improper

lubrication, or other conditions that could prevent the

systems

from fulfillingtheir functional requirements.

The inspector

noted that the oil level in the Unit 3 "A"

auxiliary feedwater

pump turbine

was

above the upper mark-

indicated

on the sight glass.

Oil had

been

added earlier that

day followino routine sampling.

The licensee initiated

a

Condition Report/Oisposition

Request

(CROR)

and is installing

improved indicators

on the,siaht

glasses

in all three units

and is sensitizing. its personnel

to be more attentive

when

monitorino the oil level.

(7)

(8)

(9)

(10)

(11)

Ouring this period,

the licensee

noted slight degradation

of

the Reactor

Coolant

Pump

(RCP) "lB" middle seal,

and.initiated

increased

monitoring of seal

performance;

Since

Nay 30,

1991,

RCP "1B" middle seal differential pressure

has steadily

decreased

about

19 percent

from 970 psid to 781 psid

as of

November',

1991.

The licensee

is principally tracking third

seal inlet pressure,

which over the

same period

has

increased

from 246 psi to 289 psi, 'an increase

of about

17 percent.

The

vendor

does not consider the middle seal failed until third

seal inlet pressure

reaches

1000 psi,

and the licensee

projects that third seal inlet pressure will be about

500 psi

at the beginning of the next Unit 3 refueling outage, if the

rate of change

remains constant.

Also, the licensee

has not

detected

a measurable

change

in seal

bleedoff flow.

The

inspector

concluded that the licensee's

monitoring activities

appear

adequate

and that no immediate

concern regarding

seal

integrity exists.

Fire Protection - Fire fighting equipment

and controls

were

S

if'dministrative

procedures.

Plant Chemistr

- Chemical

analysis results

were reviewed for

con ormance with Technical Specifications

and administrative

control procedures.

~Securit

- Activities observed for conformance with regulatory

requirements,

implementation of the site security plan,

and

administrative

procedures

included vehicle

and personnel

access,

and protected

and vital area integrity.

Plant

Housekee

in

- Plant conditions

and material/equipment

storage

were observed to determine

the general

state of

cleanliness

and housekeeping.

Radiation Protection Controls - Areas

observed

included

contro

point operation,

records of licensee's

surveys within

the Radiological Controlled Areas

(RCA), posting of r adiation

and high radiation areas,

compliance with Radiation

Exposure

I

t

14

Permits

(REP), personnel

monitoring devices

being properly

worn,

and personnel frisking practices.

The inspector

noted that personnel

performing the core offload

in Unit 2 were not wearing double rubber oloves to cross

the

hot particle control

area

(HPCA) adjacent to the refueling

machine.

This requirement

was part of'he Radiation

Exposure

Permit..(REP) briefing package,

and

had

been

discussed

with the

refueling crew during the pre-job briefing.

The licensee

discussed

this with the refueling crew and ensu'red that the

additional

gloves

were worn for subsequent

work.

The inspector

noted that personnel

working in another

HPCA

were not monitored for hot particles for over

90 minutes.

The

REP. required monitoring in accordance

with licensee

procedures.

approximately every 30 minutes.

The inspector

observed

the

hot particle monitoring after informino Radiation Protection

(RP).

No hot particles

were identified.

Licensee

management

acknowledged

at the exit meeting the

need for strict adherence

to'EP requirements.

These observations

are

examples

of an

apparently relaxed attitude toward

RP requirements

and are

cited

as v'iolations of

NRC requirements

(Violation

529/91-40-01).

(12) Shift Turnover -. Shift turnovers

and special

evolution

briefings were observed for effectiveness

and thoroughness.

One violation was identified.

4.

En ineered

Safet

Feature

ESF)

S stem Malkdowns - Units

1

2

and

3

717

0

Selected

engineered

safety feature

systems

(and systems

important to

safety)

were walked

down by the inspector

to confirm that the systems

were aligned

in. accordance

with plant procedures.

During this inspection period the inspectors

walked

down accessible

portions of the following systems.

A.

Unit I

Low Pressure

Safety Injection Trains

"A" and "B"

High Pressure

Safety Injection Trains "A" and "B"

Essential

Chilled Water Trains "A" and "B"

Containment

Spray Trains "A" and "B"

Containment

Spray Trains

"A" and "B"

Refueling Water Tank

Containment

Hydrogen Control Trains "A" and "B"

B.

Unit 2

Shutdown Cooling Trains

"A" and'"B"

Instrument Air

Containment

Hydrogen Control Trains

"A" and "8"

During the safety injection system

and shutdown cooling system

~ 'nss,

the inspector

noted occurrences

at all three units of

erroneous

valve handwheel

"OPEN" indications.

Manual

and

motor-operated

valves in the high-pressure

and low-pressure

safety

injection

and containment

spray systems

had local

handwheel

"OPEN"

indications in the wrong direction

(handwheels

being inverted) or

dual indication (arrows for "OPEN" pointing in both directions).

The licensee

has initiated

an effort to identify and correct

erroneous

valve handwheel

"OPEN" indications throughout all

safety-related

systems

by addino

a specific check to'the

system

engineer

system

walkdown checklist.

Unit 3

LowLLressure Safety Injection Train "A"

High Pressure

Safety Injection Train "A"

Core Spray Train "A"

. Essential

Batteries

(PK)

Essential

Chilled Water Trains

"A" and "8"

Refueling Water Tank

Containment

Hydrogen Control Trains

"A" and "8"

While inspecting the Unit 3 refueling water tank, the inspector

also inspected

the reactor

makeup water tank located nearby,

and

noted that the feed line to the auxiliary feedwater

system

was not

completely insulated.

The insulation stopped

before contacting

the

ground,

leaving approximately

seven

inches of piping exposed.

This

is inconsistent

with the insulation configuration of the

same

piping at Units

1 and 2.

The licensee

determined that the

installation configuration

does

not present

a freeze

problem.

The inspector

observed

the joint walkdown process,

initiated in

1989 by the licensee,

which involves the walkdown of an assigned

system

by the responsible

system engineer

and nuclear engineer.

The inspector

accompanied

the system

and nuclear engineers for two

systems;

(1) the containment

hydrogen control

system

and,

(2) the

instrument air system,

in their respective joint walkdowns.

In

both cases,

the walkdowns

had

been

scheduled

annually

and were

completed in 1990

and

1991 at all three Units as scheduled.

Each

System Engineer

used

a modified version of the general

checklist

provided in the guidance

procedures for the joint walkdown,

and

recorded

such data

as

system pressure,

work request/work

order tag

status,

system configuration,

and overall

system condition.

This

modified checklist

was .specific to the system being inspected.

Although the system engineers typically perform informal walkdowns

of their assigned

systems frequently, this joint walkdown process

appears

to be

an effective method to ensure that the system

engineer

is aware of the overall condition of his/her

assigned

system.

It also provides

a means for the nuclear engineer,

normally stationed

at the corporate office, to interface with

'his/her counterpart

in the systems

engineerino

department,

and with

the system itself, at least

once

a year.

e

I

l

During the joint walkdown of the Unit

1 containment

hydrogen

control system,

the inspector

noted

clumps of 'glue (or sealer)

on

the heat trace control panel.

The sealer

was applied

on the heat

trace setpoint

temperature

dials to prevent tampering.

These

temperature

dials

are horizontal

wheels

located

on the front of

the panel

inside

an unlocked,

glass

door.

Although th'e seal

can

be broken to adjust the dial, the application of sealer

to

an adjustable dial appears

to inhibit the operational

readiness

of that dial.

The licensee

evaluated this condition

and determined

that the dials could not

be reouired to be operated

during

recombiner operation.

If for some

reason

they did require

movement,

the inspector

determined

the, seal

could be removed.

The inspector

noted considerable

rust

on carbon steel

studs

on

several

valves in the Essential

Chilled Water system in Units

1

and 3.

System Engineering

was

aware of the general

corrosion

problem

and is evaluating the significance of the inspector's

specific observations.

The inspector

noted that the flow control valves for the essential

ventilation coolers in the

ECCS

pump rooms in Units

1

and

2 do not

have placards

warning that the valves

are reverse

acting.

Placards

are affixed to the, valves in Unit 3.

The inspector

also noted that

the essential

ventilation coolers in Units

1

and

3 lack flip-cap

covers

over the 3/8-inch diameter

temporary instrumentation

access

holes.

In Unit 3, the holes

were uncovered,

while in Unit 1,

some

were covered with plastic plugs

and

some

were uncovered.

Unit 2

coolers

had the appropriate

caps.

The licensee

stated that the

inconsistencies

between unit areas will be evaluated for

appropriate corrective action.

No violations of NRC requirements

or deviations

were identified.

I

5.

Surveillance Testino - Units

1

2

and

3

61726

Selected

surveillance tests

required to be performed

by the Technical

Specifications

(TS) were reviewed

on

a sampling basis to verify that:

~1)

The surveillance tests

were correctly included

on the facility schedule;

2)

A technically adequate

procedure

existed for performance

of the

surveillance tests;

3) The surveillance tests

had

been performed at the

frequency specified in the TS;

and 4) Test results satisfied

acceptance

criteria or were properly dispositioned.

Specifically, portions of the following surveillances

were observed

by

the inspector during this inspection period:

A.

Unit

1

Procedure

41ST-1S I03

41ST-1S I 11

Description

Containment

Spray

Pump Operability Test - 4.6.2.1.8

Low Pressure

Safety Injection

Pump Operability Test

4.5.2.F.2

0

B.

Unit 3

Procedure

Description

36ST-9SB41

PPS Transmitters

Time Response

Test

(2SGA-LT-1124A)

C.

Unit 3

Procedure

Description

36ST-9SA01

ESFAS Train A Subgroup

Relay Monthly Functional

Test

No violations of

NRC requirements

or deviations

were identified.

6.

Plant Yiaintenance - Units

1

2

and

3

62703

During the inspection period,

the inspector

observed

and reviewed

selected

documentation

associated

with maintenance

and problem

investigation activities listed below to verify compliance with

regulatory requirements,

compliance with administrative

and maintenance

procedures,

re'quired ljuality Assurance/(}uality Control involvement,

proper

use of safety taas,

proper equipment

alignment

and

use of

jumpers,

personnel

qualifications,

and proper retesting.

The inspector verified that reportabi lity for these activities

was

correct.

Specifically, the inspector witnessed

portions of the following

maintenance

activities:

Troubleshooting for ground fault on emergency lighting circuit

QBN D74A

Monitoring Equalizing Charge

on replacement

battery cells Class

1E batteries;

U.

UI

I~D

Detensioning of Reactor

Vessel

Head

Core Offload

Installation of Reactor

Vessel

FME Cover

Removal of Snubber

2SI175H022

per Snubber

Reduction

Program

Design

Change

I.

UI U~i

Retorque

and Reassembly

of operator for valve 3SGB-UV-1136B

No violations of

NRC requirements

or deviations

were. identified.

7.

Simultaneous

Reactor Trips - Units

1

and

3

92700

and

93702

J

On October 27,

1991, Units

1 and

3 were at 100 percent

power when

a grid

disturbance

occurred.

The disturbance initially caused

the closing of

two main turbine control valves in Unit

1

and all four main turbine

control valves in Unit 3.

The resultant

drop in steam flow caused

quick

4

I

10

open signals to the

Steam Bypass'ontrol

Valves

(SBCV) in both Units

and

a reactor

power cutback in Unit 3.

The main turbine control valves

reopened within

a few seconds

and the resultant

steam

demand .with both

control

and bypass

valves

open

caused

a rapid decrease

in reactor

temperature

and pressure.

The hioh reactor

power level coupled with

a

rapidly'ecreasing

temperature

caused

a variable over power reactor trip

in both units.

Subsequently,

the'Safety Injection Actuation System

(SIAS)

and the Containment Isolation Actuation System

(CIAS) actuated

in

both Units due to low pressurizer

pressure.

In both Units

1

and 3,

average

reactor coolant temperature

(Tave)

dropped

below the normal

post-trip temperature

of 564 degrees

F.

The Unit 1 pressurizer

level

reached

10 percent with the Reactor

Coolant

System

(RCS) pressure

at

of 1781 psia.

The Unit 3 pressurizer

level reached

15 percent with the

RCS pressure

at 1835 psia.

The SIAS/CIAS setpoints for all Palo Verde

Nuclear Generating

Station Units is 1837 psia;

Each Unit classified the event

as

a Notification of Unusual

Event due to

the

SIAS generated

by the low pressurizer

pressure.

Both units were

stabilized in Mode 3.

No problems with safety equipment

were noted

during this event.

The licensee

investigated

the cause

of this event.

A brief description

of the initial investigation,

other planned

actions

and preliminary

results

are provided below.

The investigation

determined that the event

was caused

by

a lightning

'trike

on

a 230 kilovolt (KV) line remote from the site.

This faulted

line was connected

via remote substation

to two 525

KV lines which were

also connected

to the site switchyard.

The lightning apparently

caused

an ungrounded

3-phase-fault.

The grid was lightly loaded with Units

1

and

3 providi'ng

a high percentage

of the power to the grid.

The fault

lasted

approximately

two cycles.

A comparison of this event with previous grid faults

showed that this

event

caused

current osci llations with lower minimum values

than

previous grid faults.

The current osci llations also continued for a

longer time during this event.

The licensee

continues to analyze the

.

differences

between

the fault which caused this event

and previous

similar grid faults which did not affect the Units.

A review of instrument traces

taken

by the Units'igital Fault

Recorders

(DFR) during the event indicated that the turbine control

valves shut in less

than 0.3 seconds

and then reopened within a few

seconds.

Three types of signals

could cause

these

valves to close;

1)

servo motor, 2) fast acting solenoid

and 3) turbine trip.

The servo

motor would require approximately two seconds

to close these

valves.

A

turbine trip dumps the hydraulic fluid and must

be reset to reopen the

valves.

Therefore,

only the fast acting. solenoid signal

had the ability

to fast close

and automatically reopen

the turbine control valves.

r

't

Only one plant circuit was connected

to the fast acting solenoid,

the

turbine

Power

Load Unbalance

(PLUB) circuit.

The

PLUB circuit was

designed

to compare turbine throttle pressure

and generator

output

current

and close the turbine. control valves

and turbine intercept

valves with high throttle pressure

and rapidly falling generator

current.

This circuit was designed

to prevent turbine overspeed'.

The

licensee

concluded that the

PLUB circuit activated to close the turbine

control valves

as described

above.

The alignment of the

PLUB circuit

was checked

and

was found to be satisfactory.

A review of the records

of the event

showed that the current osci llations which occurred

during

this event

appeared

to match criteria for activation of the

PLUB

circuit.

The licensee

obtained

a spare

PLUB circuit and fed the data previously

recorded

by the

DFR into the spare circuit using

a digital to analog

converter.

Preliminary results

indicate that the

PLUB circuit could have

activated

under conditions which occurred

on the grid, but the circuit

may not have activated

long enough to close all the control valves in

Unit

1

and the intercept valves in both Units.

The licensee

was

continuing to investigate this circuit to ensure

that the preli'minary

results

were correct.

In order to preclude future grid faults from again causing

a rapid plant

cooldown event,:the

licensee

moved the

PLUB output signal from the fast

acting solenoid circuit to the turbine trip circuit.

This modification

will preclude

automatic reopening of'he turbine control valves

and

subsequent

r apid cooling of the primary system

caused

by both turbine

control

and bypass

valves

being open at the

same time.

The licensee

also

began

a review of the turbine

and generator

control

and trip circuits. to determine if other circuits, including

a single.

fault, could cause plant cooling beyond the safety analysis.

No

circuits or single faults have

been found which could cause

cooling

beyond the safety analysis.

Following modifications to the

PLUB circuit

in Unit 3 and the determination that 'the initiating event

was

bounded

by

the Justification for Continued Operation resulting form the inadvertent

opening of steam

bypass

valves in Unit 3 on October

20,

1990,

(NRC

Inspection

Report 530/90-45),

the licensee

authorized restart of Unit 3

and

commenced

startup

on October

28,

1991.

The inspector

questioned

licensee

management

as to whether the conditions set

by the

JCO still

existed in Unit 3 since modification work had

been

done to the Unit 3

steam

bypass

control system.

The licensee

halted the startup until it

was determined that the modification was not fully implemented

and the

JCO commitments

were still being met.

The inspector

noted that

licensing

and engineering

supervisors

were cognizant of the Unit 3

JCO

status.

In addition, the inspector postulated

that

a single failure of

a turbine control valve to the fully open position during this event

sequence

might create

a condition beyond the

JCO analysis.

Licensee

safety analysis

engineers

reviewed this concern

and determined that this

failure constituted

an infrequent event

and

as

such

was bounded

by an

existing

UFSAR analysis.

0

12

Although these

questions

were resolved

by the licensee without

identifying any safety issues,

the inspector

encouraged

licensee

management

to ensure all relevant questions

have

been resolved prior to

unit restart..

The inspector

concluded that licensee

actions

taken

and planned

were

adequate

to identify a root cause

and to preclude future plant cooldown

transients

from PLUB circuit activation.

No violations of

NRC requirements

or deviations

were identified.

Cracked Batter

Cell

Unit

1

71707

On October

20,

1991, the licensee initiated Material Nonconformance

Report

(MNCR) 91-PK-1024

when

a crack

on Cell

47 of the

PKB 125

VDC

essential

battery

was found to have propagated

down the side

enough to

allow electrolyte to weep.

The licensee

jumpered out the defective cell

per Temporary Modification 1-91-PK-007. 'n reviewing the

10

CFR .50.59

safety evaluation for this modification, the inspector noticed that the

battery safety margin in the evaluation

was inconsistent

with the value

given in Calculation 13-EC-PK-161,

referenced

in the safety evaluation.

The safety evaluation

uses this incorrect value,

2.18

VDC instead of

2.81

VDC, to calculate

the safety margin with one cell jumpered.

Though

the result is incorrect,

the inspector

noted that the conclusion that

jumpering the cell

was acceptable

would not have

been

changed,

and that

the error was in the conservative direction.

However, the inspector

concluded that this is

an example of lack of attention to detail in the

review and approval of the safety evaluation.

The licensee

corrected

the safety evaluation

and,

at the exit meeting,

licensee

management

stated that they view this

as

a personnel

performance

issue

and not

a

weakness

with the review process.

No violations of NRC requirements

or deviations

were identified.

Unit 3 Restart

71707

On October

30,

1991, during reactor startup in accordance

with procedure

430P-3ZZ03,

the inspector

observed that the licensee failed to stop

Control Element Assembly

(CEA) withdrawal at the Estimated Critical Rod

Position

(ECRP) -500

pcm position

(Group

3 at 92 inches),

as required

by

the procedure.

Operators

instead

completed

a full 15 inch pull,

resulting in CEAs beino two inches

above the

ECRP -500 pcm position.

After the inspector pointed this out, operators

reinserted

CEAs to the

ECRP -500

pcm position

and then performed actions required at that

point, including evaluation of the 1/M plot to confirm that reactor

response

was

as expected.

As .1/M predictions

up to this point were very close,

and the

ECRP

(Group

4 at 60 inches)

was far off, the additional

two inch withdrawal

was not significant from

a nuclear. safety perspective.

The inspector

discussed

the situation with the shift supervisor

and the operations

supervisor,

who was also in the control

room at the time.

The assistant

t

13

10.

shi : surerv'sor

apparently did not understand

that the procedure

reauired

the withdrawal to be stopped

at the

ECRP -500

pcm position.

However, the inspector

considers

that the operators

should

be ver'

familiar with the requirements

and intent of important procedures

such

as the reactor startup

procedure.

The failure to follow procedures

is

an apparent

violation of

NRC requirem'ents

(Violation 530/91-40-02).

One violation of

NRC requirements

was identified.

Auxiliar

Feedwater

Flow Transmitter Equalizina Valves

Found Open-

Unit 3

71707

On November 4,

1991,

an Auxiliary Operator

in Unit 3 found the

equalizing valves

open for flow transmitters

3AFB-FT-41A and

3AFB-FT-41B.,

Each feedline is also monitored by,a train "A" flow

transmitter.

The licensee

entered

the action of Technical Specification 3.3.3.6 until the flow tr ansmitters

were restored to operable status.

Condition Report/Disposition

Request

(CRDR) 3-1-0192

was initiated to

document. the licensee's

investigation into the root cause

of this

condition.

The licensee

immediate performed

a 100 percent verification

of all other instrumentation

in both trains of auxiliary feedwater

and

found

no other discrepancies.

The inspector= will review the licensee's

evaluation

upon completion

(Followup Item 530/91-40-03). "

No violations of

NRC requirements

or deviations

were identified.

Refuelin

0 erations Activities - Unit 2 (71707

and

92700

During inspection of refueling operations activities, significant

discrepancies

were identified regarding

(1) failure to recognize

120

Vac

TS requirement

during core alterations,

(2) lack of senior reactor

operator supervision

(SRO) of core alterations,

(3) missed reactor

- coolant

boron sampling prior to spent fuel pool

and fuel canal

gate

opening,

and (4) lack of direct communications

between

the control

room

and personnel

at the refueling station.

These discrepancies

are

discussed

in Inspection

Report 50-528,

529, 530/91-49.

. 12.

Loss of Deca

Heat

Removal - Pro

rammed

Enhancements

Review

Generic

Le ter

L

-

emporar

nstruction

GL 88-17

recommended

various licensee

expeditious

actions

and

programmed

enhancements

for the operation of the

NSSS,

durino shutdown cooling of

the reactor,

to reduce

the risks associated

with those operations.

APS

responses

to

GL 88-17 were submitted in the following letters:

(1) Ltr

161-01597-DBK/BJA dated

January

6, 1989,

(2) Ltr 161-01614-DBK/BJA dated

February 6,

1989,

and (3) Ltr 161-04033-WFC/GEC

dated July 2, 1991.

NRC

,review and

comments

on the licensee

responses

were contained

in letters

from the

NRC to the licensee

dated

May 5, 1989,

and August 31,

1990.

The licensee's

expeditious

actions for the subject generic letter

were

inspected

and documented

in inspection reports

50-528,

529,

530/89-16

and 89-36.

The licensee's

modifications for the installation of the

Refueling Water Level Indication System

(RWLIS) was inspected

and

documented

in inspection report 50-528,

529, 530/90-23.

This inspection

was performed to verify the licensee's

programmed

enhancement

as

recommended

by

GL 88-17.

0

14

A.

Instrumentation

GL 88-17

recommended

the following:

Provide reliable indication of 'parameters

that describe

the state of the

RCS

and the performance

of systems

normally used to cool'the

RCS for both

normal

and accident conditions.

At a minimum, provide the following in

the

CR:

two independent

RCS level indications

at least

two independent

temperature

measurements

representative

of

the core exit whenever

the

RV head is located

on top of the

RY.

(The

GL suogested

that temperature

indications

be provided at all

times.)

the capability of continuously monitoring

DHR system

performance

(1)

RCS Level Indications

The licensee's

response

committed to the installation of

a permanent

RWLIS.

The

RWLIS system

had

been installed

by the licensee

in all Palo

Verde units.

The

RWLIS taps off both hot legs providing two control

room

RCS level indications.

The

RWLIS has provisions for

a backup tygon

tubing local level indication for train "A".

In addition, the

RMLIS

also includes

a local

gauge

glass

in each train that provides indication

in the minimum mid-loop level range.

RWLIS includes visible

and audible

alarms for refueling water level

LO and

LO-LO to alert control

room

operators

of RCS levels that jeopardize reliable

shutdown cooling

pump

operation; i.e. possible vortexing due to reduced level.

The licensee

neither

committed nor provided alarms for inadvertent entry into

"reduced inventory" or "mid-loop" RCS levels.

An inspection of the Unit

2 RMLIS was performed.

The hot leg connections utilize flexible

metallic braded

hose.

The use of flexible metallic braided

hose while

more rigid than rubber type

hose or tygon tubing,

appeared

to be

susceptible

to 'undesired

dips

and bends that could cause

erroneous

level

indications.

The licensee

was informed of and acknowledged

the

inspectors

observations.

Additional inspector observations

regarding

RMLIS are'contained

in the discussion

regarding

procedures.

APS'upplemental

response

to

GL 88-17 dated July 2, 1991, stated that

core exit temperatures

were available with the

RV head installed.

The

letter further stated that

upon

head removal,

the core exit

thermocouples

are withdrawn

and temperature

would be monitored using the

shutdown cooling heat

exchanger inlet temperature

indication to allow

monitoring of core exit temperature.

However,

no alarms

are normally

provided for either core exit thermocouple

or shutdown cooling heat

exchanger inlet temperature

indications.

Operating procedure

420P-2Z216

Revision 1, provided the requirements for reduced

inventory and mid loop

operations.

The procedure

required monitoring of core exit

thermocouples

during reduced

inventory and mid loop operations.

The

procedure

did not specifically require monitoring of the

shutdown

cooling heat

exchanger inlet temperature

when the

RY head

and core exit

thermocouples

are

removed.

r

15

(3)

Shutdown Coolino

S stem

SDCS

-Performance

APS's

GL 88-17 response

dated

February

6,

1989 listed numerous

instrumentation for monitoring

SDCS performance

including indications

for SDCS temperature,

pressure,

flow and

pump motor current.

It'further

listed available

alarms for the essential

cooling system that cools the

SDCS.

The letter committed to installation of

a low flow alarm for the

pumps

used for the

SDCS by the third refueling outages for Units

1

and

2

and the second refueling outage for Unit 3.

At the time of the

inspection,

the low flow alarm had not been installed in any of the

units

and the licensee

was processing

a revised

response for GL 88-17 to

delay implementation of

a design

change for the alarms to the next

ref uel ing outages for each

uni

t.'.

Procedures

GL 88-17

recommended

that licensees

develop

and

implement procedures

that cover reduced

inventory operati'on

and that provide

an

adequate

.basis for entry into

a reduced

inventory condition.

These include:

procedures

that cover normal operation of the

NSSS,

the'ontainment,

and supporting

systems

under conditions for which

cooling would normally be provided by DHR systems;

procedures

that cover emergency,

abnormal,

off-normal, or. the

equivalent operation of the

NSSS,

the containment,

and supporting

systems if an off-normal condition occurs while operating

under

conditions for which cooling would normally be provided by DHR

systems'dministrative

controls that support

and supplement

the procedures

970e04in

items (a), (b),

and all other actions identified in this

communication,

as appropriate.

Unit 2 procedures

were reviewed.

Similar procedures

existed for the

other two units.

APS procedure

420P-2SIOl,

Revision 7, provided the

instructions for initiation and operation of the shutdown cooling

system.

APS procedure

40AC-90P20 provided'he

administrative controls

for reduced

inventory and mid-loop operations.

The procedure

included

the assignment

and responsibilities for

a "mid-loop oper ation

coordinator" (the on-shift

STA) whose responsibilities

included review

of ongoing/planned

work activities for work that could cause

RCS

perturbations.

The procedure

also assigns

to the Work Control

Manager/Outage

Nanager

the responsibility of ensuring that outage

schedules

minimize work during mid-loop operations

which can perturb the

RCS,

and that the

number

and length of time the containment

equipment

hatch is to be open during mid-loop operations

is minimized.

Procedure

420P-2lZ16,

Revision 1, provided the instructions for RCS drain

operations.

The procedure

provided instructions for draining reactor

vessel

(RV) water level to either partially drained,

reduced

inventory,

or mid-loop conditions, with or without fuel in the RV.

Procedures

42AL-2RK2A, Revision 2,

and

40AL-9RK2B Revision 0,'rovide response

instructions for alarm panels

B02A and

B02B.

'Reactor

vessel

LO and

e

i

l

I

0

16

LO-LO alarms,

and essential

cooling water system

(ECWS)

alarms

were

included in panels

B02A and

B02B.

The instructions referred operators

to abnormal

operatino

procedure

42A0-2ZZ22, Revision 2, "Loss of

Shutdown Cooling," for indications of valid

ECWS trouble alarms,

essential

spray

pond system

(ESS) trouble alarms,

and

ECWS

pump

discharge

pressure

alarms.

Procedure

42AO-2ZZ22 provided instructions

for restoring 'core heat

removal

upon loss of shutdown cooling

and

isolation of the containment.

The procedure

provided five flow paths

for gravity flow and nine flow paths for forced flow.

The inspector

reviewed the

above

noted procedures

and discussed

the

procedures

with control

room operators,

system engineers

and operations

standards

personnel.

The inspector

had the following additional

comments

regarding

the procedures.

(1)

No piping

and instrumentation

diagram

(PAID) had

been

prepared for

the

RWLIS.

420P2ZZ16,

Appendix D,

and 31NT-94C41,

Appendix A,

included sketches

of the

RWLIS.

The sketches

appeared

to be the

only drawings available to the control

room operators for the

RWLIS.

The sketches

were incomplete

and contained errors.

The

420P2ZZ16

sketch contained

a wrong location for the lower isolation

valve for the

SDC Loop "B" gage glass.

Neither sketch

showed

installed level indicator drain valves

and piping.

Both sketches

appear to show the backup tygon tubing

as

always connected

when

RWLIS is connected.

In Unit 2,

RWLIS was connected

but the backup

tygon tubing was not.

Valve numbers

were not assigned

or installed

for numerous

level instrument isolation

and equalizing valves.

The inspector reiterated

the observations

documented

in inspection

report 50-528,

529, 530/90;23,

paragraph

14, that identified

some

of the

above noted discrepancies

and identified valve line up

errors experienced

by other utilities due to similar discrepancies.

Furthermore,

the inspector reiterated

the difficulties experienced

by Palo Verde Unit 3, during the Unusual

Event of Narch 3,

1989,

and the difficulties experienced

in accomplishing

valve line-ups

for manual

operation of the atmospheric

dump valves

due to lack

of valve labeling.

(2)

Procedures

40AC-90P20

and 420P-2ZZ16 required review of containment

closure status

and verification that the containment

equipment

hatch is closed,

unless specific authorization to leave the hatch

open

had

been granted

by the Plant Nanager, prior to entry into

reduced

inventory.

However, neither procedure

provided

any criteria

for allowing the containment

hatch to be left open

such

as existing

level,

decay heat,

length of time to close the .hatch, etc.

Furthermore,

neither procedure

had provisions for PRB or peer

,

review of the Plant Nanager's

authorization.

(3)

420P-2ZZ16 requires disabling of the

SDCS automatic closure

interlocks prior to entry into mid-loop conditions.

The procedure

does

not require disabling the interlocks prior to reduced

inventory operations.

e

I

I

j

i

f

17

(4.)

Numerous

less significant

comments

were provided by the inspector

regarding

420P-2ZZ16

and 40AC-90P20.

These

included appropriate

identification of equipment

and instrument

numbers in the

procedures,

assurance

of consistency

in the terminology for reduced

inventory

and mid-loops operations,

and clarification of mid-loop

coordinator responsibi l.ities.

The licensee

acknowledged

the inspector

comments.

C.

~Eui ment

GL 88-17

recommended

that licensees:

0

Assure that

adequate

operating,

operable,

and/or available

equipment

of high reliability is provided for cooling the

RCS

and for avoiding

a loss of RCS cooling.

P

Main'tain sufficient existing equipment

in an operable

or available

status

so

as to.mitigate loss of

DHR or loss of RCS inventory should

they occur.

This should include at least

one high pressure

injection

pump

and

one other system.

The water addition rate capable

of being

provided by each

equipment

item should

be at least sufficient to keep

the core covered.

Provide

adequate

equipment for personnel

communications that involve

= activities related to the

RCS or systems

necessary

to maintain the

RCS

in

a stable

and controlled condition.

The licensee's

February 6,

1989,

response

identified equipment in place

and

how they are

used for reduced

inventory and mid-loop operations.

The response

also stated that

a study of personnel

communications

equipment

would consider

design

changes

where deficiencies

are found.

The communications

study was completed in April 1990

and determined that

"the adequacy of the installed equipment for maintainino the

RCS i'

a stable

and controlled condition is marginal in many areas

of the plant."

A plant change

request

was

approved

in July of 1990.

A design

change

package

had not been

issued

at the time of the inspection.

D.

~Anal ses

GL 88-17

recommen'ded

that licensee's:

Conduct

analyses

to supplement

existing information and develop

a

basis=for

procedures,

instrumentation installation

and response,

and equipment/NSSS

interactions

and response.

The analyses

should

encompass

thermodynamic

and physical

(configuration) states

to which

the hardware, can

be subjected

and should provide sufficient depth

that the basis is developed.

Emphasis

should

be placed

upon obtaining

a complete understanding

of NSSS behavior

under

nonpower operation=.

The licensee's

response

committed to perform the various

analyses

recommended.

The analyses

were not reviewed

by the inspector.

e

1'

18

E.

Technical

S ecifications

GL 88-17

recommended

that:

Technical specifications

(TS) that restrict or limit the safety

benefit of the actions identified in this letter should

be identified

and appropriate

changes

should

be submitted.

The licensee's

GL response

identified its intent to submit.

TS chanoes

to

(1) eliminate

SDCS automatic closure interlocks

and (2) reduce

SDCS flow

rate to reduce potential for vortexing

and air entrainment.

Those

TS

amendment

requests

were submitted

by the licensee

on September

9, 1991,

and~ November

20,

1990,

but had not yet. been

approved

by NRR.

F.

RCS Perturbations

GL 88-17

recommended

that:

Item (5) of the expeditious

actions

should

be reexamined

and operations

refined

as necessary

to reasonably

minimize the likelihood of loss of

DHR.

The licensee

repsonse

to

GL 88-17 committed to performance of an

ISEG

review of RCS perturbations

to determine

the

adequacy of procedural

controls, identify activities that should not

be performed during

mid-loop operations,

or additional

measures

that should

be taken during the

performance of certain activities.

Vhile

ISEG had performed

several

reviews for specific conditions for

specific units related to reduced

inventory and mid-loop operations,

a

comprehensive

review of reduced

inventor'y and mid-loop operations for

all units

had not been

completed.

D.

Conclusions

The inspection

determined that the licensee

generally met commitments

contained

in its

GL 88-17 response.

Some actions

were late

and revised

.completion dates

were to be submitted.

Some

GL 88-17 recommendations.

were not addressed

in the licensee

response

and were identified in this

report.

All discrepancies

identified were discussed

with various

licensee

personnel for their action

as appropriate.

No violations or deviations

were identified.

13.

Review of Licensee

Event Reports - Units

1

2

and

3

92700

The following LERs were reviewed

by the Resident

Inspectors.

A.

Untt

1

None this report.

19

B.

Units

2 and

3

0 en)-LER 529/90-04-LO/Ll: '!Pressurizer

Code Safet

Valve

Set-points.

Out of To erance"

- Unit

2

and

LER 530/9 -0 -LO/Ll

"Safet

Va ve Set-points

Out of To erance

'

Unit 3

92700

The inspector

examined

the licensee's

basis for concluding that the

as-found settings for Pressurizer

and Main Steam Safety Valves

(PSVs

and

NSSVs) would not have

caused

the

RCS pressure

safety

limit to be exceeded if the limiting accident

(Loss of Condenser

Vacu'um causing turbine .trip) were to occur.

The inspector

determined that,

had the original

UFSAR assumptions

been

used,

the

analytical results

would have

exceeded

the 2750 psia safety limit

for all three Units (Unit

1 reported

PSV set-point drift in LER 528/89-07).

The licensee

relaxed three of these

assumptions

for

.

'nits

1

and 2,

and four for Unit 3 such that the analytical result

was 0.7 psia less

than the safety limit for Unit 3, 0.8 psia less

for Unit 2,

and

18 psia less for Unit 1.

The original

UFSAR result

was approximately

8 psia less

than the safety limit using original

assumptions.

Of these

relaxed

assumptions,

some were based

on using as-found

trip response

time

and trip set-point valves,

the use of which is

normal for an analysis of as-found conditions.

However, in each 'unit, two assumptions

were relaxed

based

on

changes

in modeling the plant's response.

One involved

a less

conservative

flow friction factor

and the other,

more

significantly, involved the opening characteristic

of

a PSV.

The

first relaxation gains approximately

a

22 psia

advantage

in the

final result.

The second

gains

approximately

10 psia.

The

licensee

has stated that additional conservatisms

in the

CESEC

computer

code

used to model the plant during the simulated

transient

are

between

40 to 50 psia.

The inspector

concluded that the,LER's safety

assessments

did not

clarify that the licensee's

analysis of as-found conditions

would

have

shown that using original

UFSAR conservations,

the pressure

safety limit would have

been

exceeded for the limiting event.

Furthermore,

there

was

no discussion

of the licensee's

need to

relax

some of the conservatisms,

or that even with these

relaxations that the analyzed

margin to the safety limit was

0.8 psia or less

in two cases.

During

a routine managment

meeting

in Region

V offices

on November 6, 1991, licensee

management

acknowledged

the

NRC's desire for greater specificity in LER safety

assessments

when margins

are small,

and conservatisms

are relaxed.

Licensee

management

committed to submit additional

supplements

to

these

LERs to provide further details.

20

C.

Unit 3

Closed)

530/91-04-LO:

"ESF Actuation

Due to Radiation Monitor

Failure"

This

LER describes

the July 13,

1991, failure of the "A" Power

Access

Purge

Area radiation monitor (RU-37), which resul.ted

in

generation

of

a Containment

Purge Isolation Actuation Signal

and

a

Control

Room Essential

Filtration Actuation Signal

on both trains,

as designed. 'he uhit was in Mode

1 at the, time,

and

no containment

purge

was in progress.

All equipment

actuated

as designed.

The

licersee

confirmed that

no actual

high radiation condition existed.

RU-37 failed due -to

a slightly dented Geiger-Mueller tube.

The

cause

of the dent

was not determined,

though maintenance

techni,cians

were not previously aware that minor denting could lead to detector

failure.

In .response

to this event,

the licensee

briefed its

Radiation Monitoring System maintenance

technicians

and enhanced its

model

work document to ensure

appropriate

inspections

of the

Geiger-Mueller tubes

are performed.

The monitor was repaired

and

returned to service.

The inspector

concluded that the licensee's

corrective actions

were

adequate

and appropriate.

This item is closed

on the basis

of this

1

review.

.14.

Exit Meetino

An exit meeting

was held

on November

14,

1991, with licensee

management

during w'hich the observations

and conclusions

in this report

were'enerally

discussed.

The licensee

did not identify, as proprietary

any

materials

provided to or reviewed

by the inspectors

during the

inspection.

0

ACCELERATED DISTRIBUTION DEMONSTRATION SYSTEM

v

D

I

REGULATORY INFORMATION DISTRXBUTION SYSTEM

(RXDS)

ACCESSION NBR'9201070257

DOC.DATE: 91/12/27

NOTARIZED:

NO

DOCKET I

FACIL:STN-50-528 Palo Verde Nuclear Station, Unit 1, Arizona Publi

05000528

STN-50-529 Palo Verde Nuclear Station, Unit 2, Arizona Publi

05000529

STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi

05000530

AUTH.NAME

AUTHOR

AFFILIATION'ONWAY,W.F.

Arizona Public Service

Co.

(formerly Arizona Nuclear Power

RECIP.NAME

RECXPXENT AFFILIATION

MARTIN,J.B.

Region

5 (Post

820201)

I

SUBJECT:

Responds

to concerns

raised in Xnsp Repts 50-528/91-30,

50-529/91-30

6 50-530/91-30. Corrective actions:work order

process

changed to provide for in-line review of emergency

lighting PM work orders.

S

DISTRIBUTION CODE:

IE01D

COPXES RECEIVED:LTR

ENCL

SIZE:

/

TITLE: General

(50 Dkt)-Insp Rept/Notice of Violation

esponse

NOTES:STANDARDIZED PLANT

Standardized

plant.

Standardized

plant.

RECXPXENT

ID CODE/NAME

PD5

PD

THOMPSON,M

NTERNAL: ACRS

AEOD/DEIIB

DEDRO

NRR MORISSEAUID

NRR/DLPQ/LPEB10

NRR/DREP/PEPB9H

NRR/PMAS/ILRB12

OE DIR

RE

-ILE

2

EXTERNAL: EGGG/BRYCE IJ. H.

NSIC

NOTES:

COPIES

LTTR ENCL

1

1

1

1

2

2

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

RECIPIENT

ID CODE/NAME

TRAMMELL,C

AEOD

AEOD/DSP/TPAB

NRR HARBUCK,C.

NRR/DLPQ/LHFBPT

NRR/DOEA/OEAB

NRR/DST/DIR 8E2

NUDOCS-ABSTRACT

OGC/HDS1

RGN5

FILE

01

NRC PDR

COPIES

LTTR ENCL

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

A

05000528

05000529

D

05000530

D

S

D

NOTE TO ALL"RIDS" RECIPIENTS:

D

D

PLEASE HELP US TO REDUCE iVASTE! CONTACT THE DOCUMENT CONTROL DESK,

ROOivl PI-37 (EXT. 20079) TO ELlivIINATEYOUR NAME FROM DISTRIBUTION

LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES

REQUIRED:

LTTR

26

ENCL

26