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Forwards Summary of Enforcement Conference on 890728 in Region IV Ofc Re Violations Noted in Insp Rept 50-285/89-27 Involving Inadequate Testing of Turbine Driven Auxiliary Feedwater Pump
	ML20245J906
Person / Time
Site:	Fort Calhoun
Issue date:	08/11/1989
From:	Milhoan J; NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV)
To:	Morris K; OMAHA PUBLIC POWER DISTRICT
References
	EA-89-144, NUDOCS 8908180227
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F Docket: 150-285/89-27l

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Mi Oniaha Fablic Power District >

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JATTN: Kenneth1J. Morris, Division Manager ~

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.? Nuclear Operations.

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, Gentlemen:

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iThis refers [to the Enforcement Conference conducted at Region'IV's request in

'e .the NRC, Region IV office on July 28, 1989. This meeting related to activities.

% authorized by NRC License DPR-40 for Fort Calhoun Station and was attended by

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.. Ethose listed on the attached Attendance List.

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. The subject ' discussed was. the potential violation _ documented in NRC2 Inspection

'

, Report.50-285/89-27 involving inadequate-testing of the turbine driven auxiliary -

feedwater pump.

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LAlso, during th'e meeting, you discussed your corrective actions'and' aspects of

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~your. Safety Enhancement Program which you believe would have detected this

-problem with the. turbine driven auxiliary feedwater pump. You will be advised;

by separate; correspondence of our decision relative to the disposition of the. 4

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potential violation. V

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/ A co'py 'of your. presentation' material is attached to this letter. In accordance

- 'with Section 2.790 of the NRC's " Rules of; Practice," Part 2 ' Title 10, Code of

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' Federal. Regulations, a copy of-this letter and its attachments will be placed

rin the NRC's'Public Document Room.

. Should you'have any, question concerning this matter,lwe will be pleased to

discuss them with.you.

Sincerely,

y wwfp

Thomas P. Gwyrn

'

-* 0ames L. Milhoan, Director

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Division of Reactor Projects ,

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n. 3. MEETING SUMMARY-

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. Docket:- 50-2851

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ENFORCEMENT' CONFERENCE [CONCERNINGHRC; FINDINGS (INSPECTION

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REPORT 750-285/89-27) a

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p' :On July 28,;1989, representatives of' Omaha Public Power District met with

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LRegioni1V personnel,in Arlington -Texas,~ to discuss the apparent violation

, identified during our! inspection conducted June 22-23, 1989 and the corrective-

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1 actions taken or planned by the licensee.

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EThe 11censee'sLpresentation addressed,the areas of: concern identified in the-

Enforcement Conference Agenda. A. copy of the licensee's presentation.is.

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ATTACHMENT 2

L ENFORCEMENT C6NFERENCE PARTICIPANTS

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g NRC-

T. Gwynn, Deputy Director, Division of Reactor Projects (DRP), Region IV (RIV)

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J. Jaudon, Acting Director, Division of Reactor Safety (DRS), RIV

D. Wheeler,' Acting Deputy Director, DRS, RIV

P. Michaud, Acting Chief DRP, Section B, RIV

D. Kelley, Acting Section Chief, Operational Programs Section, DRS, RIV

.R. Vickrey, Reactor Inspector, DRS, RIV

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G. Sanborn, Enforcement Officer, RIV

A. Bournia, NRR Project Manager

R. Mullikin, Project Engineer, Section B. DRP, RIV

1. Barnes, Chief, Materials and Quality Programs Section, DRS, RIV

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W. Jones, Senior Vice President

R. Mueller, Supervisor, Nuclear Project

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R. Short,' Supervisor, Nuclear Projects

J. Gasper, Manager, Training

W.'Stecker, AFW Systems Engineer

G. Peterson, Manager, Fort Calhoun Station-

R. Jaworski, Manager, Station Engineer

'S.,Gambhir, Division Manager, Production Engineer

J. Fisicaro, Manager, Nuclear Licensing and Industry Affairs

4

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_ . _ . _ . . . _ _ . _ _ _

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NRC PRESENTATION

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JULY 28,1989

Inspection Report 89-27

1. Opening Remarks W. C. Jones

11. Overview of Meeting S. K. Gambhir

lil.. Discussion of Problem R. L. Jaworski

1. Problem Discovery and Root

Cause-

O 2. Corrective Actions Taken

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3. Overall Conclusions <

IV. Generic implications and R. J. Mueller

Corrective Actions .

V. Safety Significance and j

Plant Reievance G. R. Peterson {

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VI. Summary S. K. Gambhir l

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Vll. Closing Remarks W. C. Jones

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D TEST HISTORY .

5/20/70 SHOP TESTED BY VENDOR

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1/30/73 PREOPERATIONS TEST

10/23/73 PERFORMANCE TEST

1973-1989 SURVEILLANCE TEST

5/10/79 SPEED LIMITER TEST

4/29/89 SP-FW-11, CAPACITY TEST

(TO STEAM GENERATOR)

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6/13/89- SP-FW-12, SPEED LIMITER TEST

7/13/89 SURVEILLANCE TEST IN PRESENT

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CONFIGURATION

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n CORRECTIVE ACTIONS i

AND RESULTS

1. FW-10 Operability Action

Tagged out instrument Air Supply

Result: FW-10 Operable

' * Performed 50.59 Evaluation and reviewed by PRC

Result: Bypassing Controllers Acceptable

2. Oneietinc Procedure Review

z * Reviewed EOPs for Additional Changes

O Re.uit: . no Cnanoe. Reguired

Reviewed AFW Operating instruction

Result: Revised Operating instruction

3.- FW-10 Testing

Tested Speed Limiter (6/13/89)

Result: Verified FW-10 Operable as a Constant Speed Pump

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' Reviewed AFW Surveillance Test

Result: Revised Surveillance Test

Surveillance Tested FW-10 (7/13/89)

Result: FW-10 Operable

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CORRECTIVE ACTIONS AND RESULTS (Continued)

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4. Surveillance Test Proaram Review

Reviewed IST Trend Parameters

Result: No Indication of inoperable IST Equipment Based on

Trending

5. Desian Reviews

Reviewing Requirement for Speed Controller

Result: In Progress

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Evaluated AFW System Flow I

_ Result: Verifled System and Pump Configuration Supplies Design

Basis Flows

O 6. FW-10 Maintenance

Troubleshooting of FW-10 Controller

Result: In Progress

7. Safety Slanificance Evaluation

Reviawed USAR DBAs for Consequences of Controller Failure

Result: Identified EOPs Adequately Addressed Worst Case l

Consequences

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_ _ _ - - - - -

__ _ _ - _ _ _ _ -

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O IST PEMP TEST PROGRAM

SCHEDULED

PUMP TEST DATE PURPOSE RESULT

HPSI 1988 Verify Valva Acceptable

LPSI Refueling DP and Flow

CS Outage

RW 7/89 Baseline Acceptable

Data for

Surveillance

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CCW 11/89 Baseline Data N/A

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Boric Acid 6/90 Flow Test to i

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CYCS N/A

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TOTAL P.06

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O MAJOR PROGRAM WHICH

REI ATES TO THIS ISSUE

PREVENTIVE MAINTENANCE (SEP 41)

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SAFETY- ANALYSIS REVIEW

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MAIN STEAM LINE BREAK

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SMALL BREAK LOSS OF COOLANT

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ASSESSMENT OF OPERATIONAL SAFETY

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PLANT MANAGEMENT INVOLVEMENT

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P.R.C. REVIEW

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STUDY OF PREVIOUS TEST RESULTS

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REPORTAB1LITY

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Ornaba Public Power District

1623 ti.irney o#nana. Nebrana 6H102 224 7

402 536 4000

July 17, 1989

LIC-89-549

U. S. Nuclear Regulatory Commission

Attn: Document Control Desk

Mail Station P1-137

Washington, DC 20555

Reference: Docket No. 50-285

Gentlemen:

,

SUBJECT: Licensee Event Report 89-016 for the Fort Calhoun Station

Please find attached Licensee Event Report 89-016 dated July 17, 1989.

This report is being submitted per requirements of 10 CFR 50.73

(a)(2)(1)(2) and 50.73(a)(2)(ii)(B).

If you. should have any questions, please contact me.

Sincerely,

p

,

/

K .LJ'. orris

Division Manager

Nuclear Operations

KJM/ tem

Attachment

c: R. D. Martin, NRC Regional Administrator I

A. Bournia, NRC Project Manager

P. H. Harrell, NRC Senior Resident Inspector

INP0 Records Center

American Nuclear Insurers

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LICENSEE EVENT REPORT (LER) ''"'88=

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_-4817 seamt til DOCKir aumsta tag e aG5 .J.

Fort Calhoun Station Unit No. 1 015 I o e o I o !21815 1 lod 014

TlTLE te#

. Auxiliary Feedwater Pump FW-10 Outside Design Basis

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On June 16, 1989 Engineering evaluation of test results revealed that, for an

unknown period prior to June 14, 1989, Auxiliary Feedwater Pump FW-10

operability was outside the design basis for certain accident conditions due to

inoperability of the pump pneumatic speed control loop. Problems with the

control loop had been found on June 13, 1989 after FW-10 was taken out of

service for special testing. These problems would have limited pump speed and

discharge pressure below that needed to inject water into the steam generators

under some accident conditions. Because the control loop could not be repaired

and tested expeditiously, the air supply to the control loop was valved out on

June 14, 1989. This allowed pump speed and discharge pressure to be controlled

by the mechanical speed limiter on the main governor as designed to meet

accident mitigation criteria. The pump was determined to be operable and

returned to service. An investigation was initiated to determine the duration

and cause of the control loop inoperability. The NRC Regional Office was

briefed on June 13, 1989 and, following the determination of deportability, the

NRC Operations Center was notified on June 16, 1989 at 1646 hours0.0191 days 0.457 hours 0.00272 weeks 6.26303e-4 months , pursuant to

10 CFR 50.72(b)(1)(ii). Fort Calhoun Station Unit No. I was at approximately

100% power at the time of determination. An action plan has been implemented

{ } to determine root cause of the control loop failure, formulate corrective

actions, and address NRC questions and concerns. Results of these actions will

be presented in supplements to this report.

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Auxiliary Feedwater Pump FW-10 is one of two redundant auxiliary feedwater

pumps at Fort Calhoun Station Unit No.1. FW-10 is a steam turbine driven pump

designed to De independent of AC power requirements, while redundant pump FW-6

is an AC motor driven pump. Each pump is designed to deliver a minimum flow of

260 gallons per minute (gpm) to the steam generators against a steam generator

pressure of 1000 psia. During normal startup and shutdown operations, pump

FW-6 is routinely used to supply feedwater. Pump FW-10 is not normally used

for plant operations and is usually only run during testing.

The speed (and resultant discharge pressure) of FW-10 is designed to be

governed by a pneumatic-hydraulic t(need control loop which maintains the feed

pump discharge pressure at a fixed 61?Tenntial greater than the steam

generator pressure. A Moore differ %tici pressure transmitter senses the

differential pressure between the ,.uso discharge and the steam generator and

sends a signal to a pneumatic controller. The Nullmatic Two-Mode Model 55M

controller feeds an air signal through a Nullmatic Model 59 derivative

controller unit which dampens the signal to reduce pump speed oscillation.

O This should permit smooth response to a pump speed needed to provide discharge

pressure above steam generator pressure. The differential pressure setpoint is

adjustable in the field, and would normally be set so that the pump discharge

pressure is at least 40 psi above the steam generator pressure at rated flow.

The pump control system is supplied from the Instrument Air System. The

control system is also designed to allow maximum speed of the pump upon total

loss of Instrument Air. In this condition, pump speed is limited by the

setting of the mechanical speed limiter on the main governor. As originally

installed, the speed control loop did not provide for manual control of pump

speed.

At 1300 hours0.015 days 0.361 hours 0.00215 weeks 4.9465e-4 months on June 13, 1989, with the station operating at 1007. power, pump

FW-10 was taken out of service in preparation for testing following redundant

coutponent testing of pump FW-6. Technical Specification 2.5 allows one

auxiliary feedwater pump to be inoperable for up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The testing

(controlled by procedure SP-FW-12) was intended to provide baseline data on

pump performance by developing a method for manual control of pump speed, in

order to 1stablish a reference speed for future testing and verify the

governor-limited maximum speed. Temporary modification 89-M-031 was

implemented, which installed a variable air supply test-tee inlet to the {

control loop in order to simulate signals from the differential pressure sensor

and provide manual pump speed control to the test personnel. At 1645 hours0.019 days 0.457 hours 0.00272 weeks 6.259225e-4 months ,

FW-10 was started and warmed up for the test. At 1727 hours0.02 days 0.48 hours 0.00286 weeks 6.571235e-4 months the test air

supply was valved in and initial readings were taken. Between the hours of

1750 and 1835 the test air pressure signal was varied numerous times with no j

change in pump speed observed. At 1835 hours0.0212 days 0.51 hours 0.00303 weeks 6.982175e-4 months the pump was stopped and the

e control system was returned to normal configuration. The Shift Supervisor,

Duty Supervisor, System Engineering Supervisor, and Plant Manager were informed

of the situation. i

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At 2000 hours0.0231 days 0.556 hours 0.00331 weeks 7.61e-4 months on June 13 an emergency maintenance order was initiated to

investigate and make minor repairs to the pneumatic controller and derivative

unit. This activity included cleaning of restriction orifices and checking

adjustments of the controller as described in the vendor manual. The

pneumatic derivative unit was found to be leaking air and to have erratic

response. No other repairs or adjustments were possible at the time. With the

control components in this condition, pump FW-10 maximum speed was found to be

6980 rpm with a resultant discharge pressure of 996 psig, a value below the

minimum pressure assumed for operability.

Test procedure SP-FW-12 was revised to allow determination of the mechanical

limiter setpoint on the main governor for FW-10 by injecting the test signal

downstream of the derivative unit. The test revealed on June 14 at 1005 hours0.0116 days 0.279 hours 0.00166 weeks 3.824025e-4 months

that, upon loss of instrument air supply, pump speed would increase to 7725 rpm

with a discharge pressure of 1210 psig. In this mode the pump was considered

operable, since the speed and discharge pressure were well above the design

basis minimum values, yet pump speed was within the maximum allowable. It was

/3 determined that failure analysis and repairs of the pneumatic controller

C components could not be accomplished within the remaining degraded mode period

allowed by the Technical Specifications, so the instrument air supply to the ,.

control system for FW-10 was valved out. The pump was restarted to verify that

it would perform its intended safety function in this configuration; it was

subsequently declared operable and returned to service at 1130 hours0.0131 days 0.314 hours 0.00187 weeks 4.29965e-4 months on June 14

with the instrument air supply valve tagged closed.

It could not be immediately determined what caused the malfunction of the

controller system or when the system became inoperable. An evaluation

including review of previous test data was initiated in order to determine

deportability. Because of the significance of the event, the situation was

explained to the NRC Region IV office by plant management on June 14. The

engineering evaluation concluded on June 16, 1989 that FW-10 controller loop

performance was degraded; the plant thus operated outside the design basis of

the auxiliary feedwater system for an indeterminate period. This was reported

to the NRC Operations Center on June 16, 1989 at 1646 hours0.0191 days 0.457 hours 0.00272 weeks 6.26303e-4 months pursuant to 10 CFR

50.72(b)(1)(ii). As an additional consequence, the Limiting Condition for

Operation (LCO) of Technical Specification 2.5 was violated for an

indeterminate period.

This event is safety significant to the degree that, under certain conditions,

Auxiliary Feedwater Pump FW-10 would not have been capable of performing its

function. These conditions would be the coincident (1) loss of main feedwater,

(2) unavailability of motor-driven Auxiliary Feedwater Pump FW-6, (3) steam

g) generator pressure over approximately 1000 pria, and (4) availability of

Instrument Air supply to FW-10. The pneumatic controller problems limited

O' FW-10 discharge pressure to approximately 996 psig. If conditions (1), (2),

and (3) occurred along with a total loss of instrument Air supply, FW-10 would

have been operable, since the pneumatic control system would be essentially

bypassed on loss of air.

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Both auxiliary feedwater pumps are designed to automatically start on low steam

generator level. If a loss of all station AC power also occurs. FW-10 is the

primary source of feedwater. A loss of all station AC power will eventually

cause a total loss of instrument air, a situation where FW-10 would be

operable. Also, motor-driven pump FW-6 is powered from an emergency diesel

generator when normal AC power supply is lost.

Determination of cause and corrective actions for this event are not complete

at this time; consequently, a list of similar occurrences reported previously

can not be provided until this determination is completed. A detailed root

cause investigation of this event is still being performed as part of action

items identified by plant staff and questions from NRC Region IV inspectors.

The action plan items currently include:

(1) Determine the direct cause of the derivative controller failure in the

FW-10 speed control loop.

c (2) Determine the root cause of the failure of FW-10 to respond to manually

l injected air signals during the conduct of SP-FW-12.

V) (3) Review and evaluate available information to ascertain, if possible, when

failure /misadjustments of the speed control components occurred.

(4) Review previous testing of FW-10 to determine if the failure of the speed

control loop should have been evident from the data available. Evaluate

the effectiveness of the existing surveillance tests on FW-10 used to

demonstrate operability.

(5) Investigate why the speed control loop components have had no equipment

identification numbers, calibration procedures, or periodic maintenance.

Evaluate whether speed centrol loop components are correctly classified

with respect to EEQ, safety class, and procurement class (COE, etc.).

(6) Evaluate the design basis of and the need for the differential pressure

controller on FW-10.

(7) Evaluate a loss of instrument air event to determine, if possible, the

length of time between the loss of air and the instrument air pressure

dropping low enough to cause FW-10 to operate on the speed limiter.

Include an evaluation of the impact of this time delay on events involving

a demand for FW-10.

(8) Evaluate the as-found condition of FW-10 for a loss of main feedwater

design basis event concurrent with failure or unavailability of FW-6.

The action item completion is scheduled as follows: Items (1) through (5) will

be completed and the results documented in a supplement to this LER by

September 1, 1989. Items (6) through (8) will be completed and the results

documented in another supplement to this LER by December 1,1989. Specific

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7- corrective actions and commitments will be noted in these supplements.

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