ML20148H790

Insp Repts 50-324/88-06 & 50-325/88-06 on 880125-29. Violations Noted.Major Areas Inspected:Area of Inservice Testing of Pumps & Valves

ML20148H790
Person / Time
Site:	Brunswick
Issue date:	03/02/1988
From:	Blake J, Girard E NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20148H775	List: ML20148H770 ML20148H778 ML20148H790
References
50-324-88-06, 50-324-88-6, 50-325-88-06, 50-325-88-6, NUDOCS 8803300083
Download: ML20148H790 (15)

See also: IR 05000324/1988006

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' [kQ 080g UNIVED STATES l

/ 'o NUCLEAR REGULATORY COMMISSION 1

[ n REGloN 11 )

j 101 MARIETTA STREET, N.W.

S

• '.. 'f ATL ANTA, GEORGI A 30323

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Report Nos.: 50-325/88-06 and 50-324/88-06

Licensee: Carolina Power and Light Company

P. O. Box 1551

Raleigh, NC 27602

Docket Nos.: 50-325 and 50-324 License Nos.: DPR-71 and DPR-62

Facility Name: Brunswick 1 and 2

Inspection C du d- nuary 25-29, 1988

Inspecto : - // ' '

E B

j f tE rd D' ate' signed

Appro ed by _ _ f .

7' &

J.J.faiake, Chief Date Signed

Pt ials and Processes Section

j iv sion of Reactor Safety

SUMMARY

Scope: This routine, unannounced inspection was in the area of inservice

testing of pumps and valves.

Results: One violation was identified involving deficiencies in valve testing

procedures and failures to follow the procedures.

8803300083 830310

PDR ADOCK 05000324

O DCD

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REPORT DETAILS

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1. Persons Contacted

Licensee Employees

S. Boyse, Project Engineer, Technical Support

• R. Creech, Instrumentation and Control Supervisor (Unit 2) Maintenance

• J. Crider, Inservice Inspection Responsible Engineer, Technical Support

C. Dietz, Plant General Marager

W. Dorman, Quality Assurance Supervisor, QA/QC

• K. Enzor, Director, Regulatory Compliance

• L. Jones, Director, QA/QC

• W. Martin, Principal Engineer, On-Site Nuclear Safety

• J. O'Sullivan, Manager, Maintenance

C. Patterson, Inservice Inspection Project Engineer

• R. Poulk, Project Specialist - NRC, Regulatory Compliance

• J. Simon, Engineer, Operations

• L. Wheatley, Inservice Inspection Project Engineer, Technical Services

• E. Wilson, Engineering Supervisor (Nuclear), Technical Support

• A. Worth, Engineering Supervisor (Discipline), Technical Support

NRC Resident Inspector

• W. Ruland, Senior Resident Inspector '

• Attended exit interview

2. Exit Interview

The inspection scope and findings were summarized on January 29, 1986, -

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with those persons indicated in Paragraph 1. The inspector described the

areas inspected and discussed in detail the inspection findings. -

Dissenting comments were not received from the licensee.

Item Number Status Title / Reference Paragraph

325, 324/88-06-01 Open Violation - Inadequate stroke

time testing of air operated I

valves (Paragraph 4)

Proprietary information is not contained in this report.

3. Licensee Action on Previous Enforcement Matters l

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This subject was not addressed in the inspection.

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4. Inservice Testing of Pumps and Valves (73756) - Units 1 and 2 .

The NRC inspector examined selected examples of the licensee's inservice i

testing of pumps and valves to verify compliance with licensee commitments '

and regulatory requirements. Based on Technical Specification (TS)

4.0.5.a.2,10 CFR 50.55a(g), and on NRC approval letter dated April 8,

1987, the licensee is currently required to test their pumps and valves in

accordance with ASME Section.XI (80W81).

The inspector directed his examination primarily to the licensee's past

testing and evaluation of the test results from four Unit 2 Containment

Isolation Valves (CIVs) which failed to close in a recent actuation. In

addition, the inspector examined the testing of the licensee's Loop B

Residual Heat Removal (RHR) pumps and of four RHR valves that are tested

along with those pumps. Details of the inspector's examinations and

findings are described below.

a. Containment Isolation Valves Which Failed to Close in Response to

Isolation Signal on January 2,1988

(1) Background Information on CIVs

On January 2,1988, the Unit 2 valves required for containment

isolation of flow from the drywell floor drain and equipment

drain failed to close in response to an automatic .(closure)

actuation signal.

Subsequently, the failure event has been extensively

investigated by the licensee. Prior to the inspection described

herein, NRC examination of the event had included a preliminary

assessment by the Resident Inspector and a special inspection of

the matter by a nine person NRC Augmented Inspection Team (AIT).

This inspector reviewed background information, including the

status of ongoing licensee investigation, through discussions

with AIT members and licensee personnel and through review

of the AIT Inspection Report (Report No. 325, 324/83-03). The

following background data was noted by the inspector relevant to

his examination of the testing.

(a) Description of Valves and Event

The failed valves are identified 2-G16-F003, -F004, -F019

and -F020. Valves 2-G16-F003 and -F004 are in the drywell l

floor drain system piping and valves 2-G16-F019 and -F020  ;

in the drywell equipment drain system piping. They are

components of the Primary Containment Isolation System i

(PCIS). The valves are three inch, 150 lb. gate valves

manufactured of cast carbon steel. The valves are opened

by an air actuation cylinder, controlled by Automatic

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Switch Company (ASCO) solenoid valves, and are spring

assisted closed upon loss of air pressure. The PCIS is a

safety-related system that is designed to prevent or liLit

the release of radioactive materials that may result from

postulated accidents through rapid, automatic isolation of

process lines which penetrate the primary containment.

F003 and F019 are powered through relay K17 and F004 and

F020 through relay K18. A single failure of either circuit

to open would not cause a loss of containment integrity, as

one valve in each line would still close.

(b) Modification to Valves

The solenoid valves which control the opening and closing

of the air supply to the subject Unit 2 CIVs were modified

to meet the Environmental Qualification (EQ) requirements

of 10 CFR 50.49 in April 1986.

Virtually identical Unit i valves (1G16-F003, F004, F019

and F020) had been similarly modified in April 1985. Due

to an error, the licensee installed ASCO Model 206-832 G

solenoids which fail open. Af ter consultation with the

vendor, they modified the valves to fail closed by replacing

the valve springs with the springs from a Model 206-832,

Type "F", rebuild kit.

(c) Previous History of Failures and Maintenance

Neither the Unit i nor Unit 2 valves experienced any

closure failures like those in the January 1988 event prior

to the modification referred to in (b) above. The Unit i

valves continued to operate satisfactorily following the

modification, while the Unit 2 valves experienced six

apparent failures. The closure tests, test failures and

the post failure maintenance that was performed on the i

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valves following EQ modification are listed in Table 1.

Stroke time data included in Table 1 is discussed in 4.f

below. The licensee identified two of the failures listed ,

in Table 1 as being the result of not holding the actuation l

switch in the closed position for a sufficient period.  ;

That is, they were not considered hardware failures.  !

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However, the inspector notes that no similar problems were l

identified in Unit 1 valve testing. Also, Region II

specialists who have reviewed the actuation circuit

consider it unnecessary to hold the switch in position.

(d) Post Event Licensee Actions to Actuate CIVs l

About 3 minutes after a manual scram of Unit 2, the Control

Operator (CO), who had started verifying the valve

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isolations, noted that valves 2-G16-F003, F004, F019 and

F020 had not automatically closed as required. He then

attempted to manually close the four valves. 2-G16-F003 ,

and -F004 closed immediately vhen the handswitch was placed

to CLOSE position (3 minutes af ter the scram). 2-G16-F019

and -F020 did not close on n.snual switch actuation. He

cycled 2-G16-F019 and -F020 switch to CLOSE three to five

times each, holding for 5 to 10 seconds in CLOSE position

each time. 2-G16-F019 and F020 remained OPEN.

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The Unit 1 Shift Foreman (SF) then also attempted to close

valves F019 and F020 by holding their switches in the CLOSE

position for more than 10 seconds. 2-G16-F019 and -F020

remained OPEN.

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Approximately two minutes later (eix .iinutes after the scram)

the SF (Unit 1) noted that 2-G16-F020 valve had CLOSED and

that 2-G16-F019 was still OPEN. The SF held the manual

switch for 2-G16-F019 in CLOSE . position for an additional

10 seconds. 2-G16-F019 remained OPEN.

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After another two minutes the SF noticed that 2-G16-F019 had

CLOSED (eight minutes after the scram).

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(e) Post Event Licensee Investigations into the Cause of the

CIV Failures

(i) Shortly after the event, the operability of the Unit i

valves was verified through manual cycling and a logic

test. The valves functioned nonnally.

(ii) Various logic and other tests of the Unit 2 valves

were conducted and, in each instance, the circuits and

valves exhibited apparently normal actuation - save

for an instance where the red (OPEN) light on F003 was

slow to extinguish. The red light stayed on for

almost 10 seconds and was illuminated concurrently

with the green (CLOSE) light. The position lights are

activated by limit switches located at the beginning

and end of valve stroke travel. Actuation causes the

valve disk to (1) move from the initial limit switch l

- causing that position light to extinguish (2) to i

between the open and closed limit switches - with no

position light on, and finally (3) to the other limit

switch which will cause that position light to l

illuminate. Based on tests of the valves observed by I

the NRC inspector in his examination of this matter,

the open light should extinguish about one second after

valve actuation.

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(iii) The solenoids were suspected as a likely cause of the

failure because of the valve closure failures

experienced subsequent to the solenoid replacements in

April 1985. Thus, the solenoids have been closely

checked in the post event investigation:

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The licensee removed the solenoid from valve

2-G16-F019 and tested it with 35 psi (normal) and

5 psi air pressure. The solenoid performed

satisfactorily at both pressures. The solenoid

was disassembled and inspected. The inspection

revealed minor debri, a light oil film in the

solenoid body and s darkened area on one solenoid-

stem. Bottom disk travel was found +7. mils out

of tolerance. None of these conditions appeared -

severe enough to explain the valve failure.

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The solenoids from 2-G16-F003 and F020 were

removed and inspected and no problems were ,

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identified, though minor debri and an oil film

like that in F019 were noted. The vendor's

representative participated in inspection of the

F020 valve solenoid. The vendor representative

did not identi fy any deficiencies in the 4

solenoid.

(iv) The air cleanliness, pressure regulator and in-line

filter serving F003 were checked and determined

acceptable.

(v) 'he logic relays K17 and K18 were inspected and

widence of arcing and sticking were noted on K18.

This might provide some bearing on the failure of F004

and F020 (both on K18) had it not been for the fact that

when F004 closed in manual actuation following the

event, the F020 valve would not close when similarly

actuated.

(vi) The air actuator of F020 was removed and inspected.

The actuator was in good condition but contained a

liberal amount of grease. In valve actuation, air

passes from the actuator through the solenoid. The

possibility that hydrocarbons from the grease may be

reaching the solenoid seats and causing sticking is

being investigated.

(vii) The valves are stroke timed quarterly in accordance

with ASME Section XI requirements. A review of stroke

time data from the F003, F004, F019, and F020 valves

in Unit 2 indicated some apparently abnormal

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unexplained changes in stroke time in past tests.

There was no clear evidence of instances where these

would predict impending failures prior to their

occurrence.

(viii) Additional licensee investigative actions planned or  ;

in progress include:

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Additional vendor inspection of the failed ASCO

solenoids

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Analysis of the oily film found in the solenoids

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Removal .and inspection of Unit 1 solenoids and

actuators

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Evaluate training on solenoid maintenance

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Evaluate differences between plant maintenance

procedures for the solenoids and the vendor's

recommendations

(f) NRC Inspector's Examination of Inservice Testing

As previously stated above, unusual changes in stroke times

were apparent in the licensee's data for the failed CIV. '

Concern that the licensee had not adequately addressed

these changes when they occurred was expressed in the NRC

AIT Report 325, 324/88-03. In the current inspection the i

NRC inspector examined the stroke time data extensively,

taking into account the test procedure and valve design.

The inspector also observed performance of stroke timing on l

Unit 1 valves 1-G16-F003, F004, F019 and F020. ,

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As an almost separate item, the inspector reviewed past

licensee leak test data for these valves.

The inspector's review, observations and his findings

are described below:

(1) Stroke Timing of Units 1 and 2 CIVs G16-F003, F004, F019 i

and F020

The inspector reviewed the stroke time data recorded

by the lierisee in their testing of the subject Unit 2

CIVs and also reviewed the data for the similar Unit 1

CIVs. The review was performed to assess the

licensee's past testing of the valves, determine if l

the test data variability noted by the NRC AIT could  !

be explained, and to determine whether the past test  !

data could be used in predicting the valve failures or

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establishing their cause. A ch*onological tabulation

of the stroke time data and maintenance actions for

the Unit 2 valves was prepared by the NRC inspector

and is given in Table 1. A chronological listing of

the similar Unit 1 stroke time data, also prepared by i

the inspector, is given in Table 2. For use in

identifying abnormal stroke time values, the inspector i

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calculated a mean and standard deviation for the first )

five tests of the Unit 2 and Unit I valves (a standard  !

normal distribution was assumed). These means and I

standard deviations are identified in the Tables. In

addition, the NRC inspector identified the stroke

times in the tables which differed from the means by two

and by three standard deviations. If the distribution of

stroke timer from the licensee's tests are normally

distributed. as would be expected, approximately 95%

of test times should (normally) fall within twe standard

deviations of the mean and 99.7% should fall within

three standard deviations. It is common statistical  !

practice to consider values that differ by more than i

three standard deviations from the mean to be abnormal. l

To aid in understanding the test data, the inspector i

reviewed the design of the valves with a maintenance i'

supervisor and reviewed the testing and test data

evaluation procedures -

identified PT-11.3 and

ENP 16.1, respectively. Additionally, the inspector

witnessed stroke time testing performed on Unit 1 l

valves 1-G16-F003, F004, F019 and F020. From his  !

review and his observation of testing, the NRC i

inspector identified the following deficiencies in the l

licensee's testing of the valves: l

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For valves with stroke times less than 10

seconds, ASME Section XI requires that, when the

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stroke time incresses 50% or more, the test

i frequency shall be increased to monthly until l

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corrective action is taken.  !

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Valves 2-G16-F004, F019 and F020 experienced

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stroke time increases exceeding 50% on August 7, .

1986 and April 27, 1987. F020 experienced over I

a 50% increase in stroke time on July 28, 1987.  !

Test frequency was not increased to monthly and i

no corrective action was taken, j

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The licensee's engineering procedure ENP-16.1,  !

Pump and Valve Graphing, Section 5.2.12, requires I

] valves with & stroke time between zero and five

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seconds to be tested monthly until the next ,

regularly scheduled surveillance if the stroke i

g time increases by more than two seconds.

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Although the licensee's ISI Project Engineer

stated that the licensee actually adhered to the

more stringent ASME requirement described above,

even the ENP 16.1 requirement was not met. Test

frequency was not increased to monthly when

stroke time increases exceeding two seconds were

experienced for valve 2-G16-F020 on August 28,

1987 and April 27, 1987 and valve 2-G16-F019 on

April 27, 1987 and August 7, 1986.

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ASME Section XI, requires the reporting of any

abnormality or erratic action that occurs in

stroke timing power operated valves. By

implication, the reporting process includes  ;

recognition of the abnormal or erratic action and  ;

evaluation to assess the need for corrective

action. The licensee failed to report and  ?

evaluate many examples of abnormal changes in

stroke time. Assuming a standard normal

distribution and utilizing the stroke times from )

the first five tests of the subject Unit 2 CIVs 1

after their April 1986 modification the calculated

stroke time mean = 3.17 seconds with a standard  !

deviation = 0.27 seconds. Statistically, stroke

times differing from the mean by more than 3

standard deviations are considered abnormal. On  ;

this basis, abnormal stroke times were i

experienced but were not recognized, reported or

evaluated for the following valves and test ,

dates: 1

2-G16-F003 tests on October 29, 1987,

June 20, 1987 and October 25', 1986

2-G16-F004 tests on January 25, 1987,

July 30, 1986 and July 24, 1986

2-G16-F019 tests on January 25, 1987, 1

July 30, 1986 and July 24, 1986

2-G16-F020 tests on July 28, 1987,

January 25, 1987, July 30, 198C, July 24,

1986 and July 17, 1986

Evaluating Unit I stroke time data in a similar j

manner, the calculated stroke time mean = 3.13 i

seconds with a standard deviation = 0.23 seconds

(values suprisingly close to those obtained for

the Unit 2 valves). Again identifying "abnormal"

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stroke times as those that-differ from the.mean

by more than 3 standard deviations, the following

tests should have been (but were not) recognized,

reported or evaluated as abnormal valve action:

1-G16-F004, F019 and F020 tests on November 2,

1987

The licensee had no criteria for identifying,

reporting or evaluating abnormal- or erratic

stroke times.

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A$ME Section XI requires the licensee to determine

the full-stroke time for the subject Unit 2

(and similar Unit 1) valves. Full-stroke time

is defined as that time interval from initiation

of the actuating signal to the end of the

actuating cycle. The NRC inspector determined

that the licensee's procedure for testing the

subject Unit 2 valves and similar Unit 1 valves

specified erroneous criteria for determination

of full-stroke time. The procedure, PT 11.3,

Drywell Drains System Valve Operability Test,

specifies that stroke time is to be measured

from switch actuation until the red (OPEN) light

extinguishes. For the subject air operated

valves, the red light extinguishes at the first

stage of valve movement as valve motion leaves

the first (red light actuating) limit switch.

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The time required for the value to complete its

stroke by moving from the OPEN switch to trip

the CLOSED (green light) switch is omitted in

the licensee's procedure. At the inspector's

request, the licensee stroke timed the Unit 1

valves 1-G16-F003, F004, F019 and F020 in

accordance with PT 11.3 and again correctly. The

testing, which was observed by the inspector,

demonstrated that valve full-stroke time was

over twice the time obtained by following

procedure. Comparative data, obtained in the

testing, is shown in Table 3.

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Based on discussion with a licensee test person

and on the licensee's recorded test data, it is

apparent that test personnel usually did not

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follow the erroneous procedural criteria for

determination of full-stroke time, but rather

used correct criteria.

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The current revision of PT 11.3 (Revision 12)

was approved November 2,1984 and the licensee's

records indicate over 30 instances of its use

since that approval. Although the Operations

personnel who performed the procedure apparently

understood how the stroke timing should be

performed (and usually performed it correctly),

the erroneous method of stroke timing specified

in the procedure was not promptly identified or

corrected and was occasionally used.

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The licensee informed the inspector that most,

if not all, of their procedures for stroke timing

air operated valves contained the same error as

in Procedure PT 11.3.

The deficiencies described above represent a violation

of TS 4.0.5 requirements to perform valve testing in

accordance with ASME Section XI and of TS 6.8.1

requirements to properly establish, implement and

maintain written procedures for safety related-

equipment (e.g. valve) testing. This violation is

identified as violation 325,'324/88-06-01, Inadequate

Stroke Time Testing of Air Operated Valves.

The NRC inspector was able -to at least in part,

explain abnormal stroke times experienced by the

licensee in testing valves 2-G16-F003, F004, F019 and

F020. However, the inspector did not identify any

trends or indicators in the licensee's stroke times

that would aid in predicting the failures experienced

or their cause. The inspector notes, however, that

indicators or trends may have been present that were

undetected due to the insufficient control of the

testing. The inspector encouraged the licensee to

make an effort to perform their stroke timing more

accurately. Improvements might be readily obtained

through increased motivation and better training and

procedures.

(ii) Leak Rate Testing of Units 1 and 2 CIVs G16-F003, F004,

F019 and F020

The inspector reviewed licensee leak rate test results

for the subject valves to verify that testing was

performed at the required frewency. was acceptable,

and whether the datt contained say evidence of the

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cause s' the closure failures that have been

experiencea. For Unit 1 the inspector reviewed

results obtained since May 19, 1977 and for Unit 2

results obtained since January 27, 1979 were reviewed.

The inspector did not identify any deficiencies in the

testing from this review and there was no evidence

suggesting a cause of the recent closure failures,

b. Loop B RHR Pumps and Valves

The inspector reviewed completed records of procedure PT 8.2.2b,

LPCI/RHR System Operability Test - Loop B, to verify that testing and

evaivation had been performed in accordance with procedural and ASME

Section XI regt.irements. The inspector checked the records for all

of Units 1 and 2 Loop B RHR pumps and for four valves, The

components and the test dates of the records reviewed are as follows:

Component Test Dates

Pump 1B 1/22/88, 10/18/87, 8/7/87, 7/26/87,

7/25/87, S/1/87, 12/20/86  ;

Pump 10 Same as above j

Pump 28 10/31/87, 8/8/87, 5/16/87, 2/22/87,

2/20/87, 2/19/87, 12/4/86

Pump 2D Same as above

Valve 1-E11 - F007B Same as Dump 1B i

Valve 1-E11 F0118 Same as Pump 1B i

Valve 1-E11 - F017B Same as Pump 1B

Valve 1-E11 - F016B Same as Pump 1B

Valve 2-E11 - F0078 Same as Pump 2 B except no test 2/20/87

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Valve 2-E11 - F0118 Same as Pump 2B except no test 2/20/87 l

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Valve 2-E11 - F0178 Same as Pump 2B except no test 2/20/87

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Valve 2-E11 - F016B Same as Pump 2B except no test 2/20/87 I

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No violations or deviations were identified during the above reviews with I

the exception of the violation noted in paragraph 4.a(1)(f).

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TABLE 1

CHRONOLOGICAL TABULAllON Of CLOSURE STROKE TIMING AND MAINTENANCE FOR

UNIT 2 VALVES 2-G16-F003, F004, F019 and F020 *

Date St roke T imes ( Seconds ) for Valves Maintenance

19Q1_ F004 FQ19 f_QRQ

10/29/87 5.0/ Failed 3.0 2.5* E 004 so l eno i d wa s rebu i l t a r te r ra l l u re - it then passed

7/28/81 3.6 2.9 3.4 4.9/

F003 solenoid was rebuilt af ter railure - it then passed

7/17/87 Failed --- --- ---

6/20/87 2.31/ 2.41* 3.02 2.49'

4/27/87 2.38" 2.60* 3.14 2.99

None-believed caused by not holding F003 switch closed. Subsequent

4/27/87 failed --- --- ---

actuation resulted in closure

1/25/87 3.62 .72/ .98/ .84/

10/25/86 3.81/ 2.95 3.43 2.97

G/7/86 2.95 3.13 3.45 2.74

7/31/86 --- --- --- --- f003 solenoid rebui l t a f ter ra i lure - it then passed.

7/30/86 Failed 1.27/ 1.30/ 1.12/ See 7/31/86

7/25/86 2.70 3.04 3.41 2.99

7/24/86 2.6* 2.2/ 2.1/ 2.0/

7/17/86 2.8 2.90 3.29 3.80/

7/13/86 3.06 2.87 3.41 3.07

7/12/86 None - intended solenoid replacement but had wrong replacement. Valve

cycled acceptably when tested with old solenoid. Test f requency was

increased ( 7/15/86 request)

7/11/86 Failed _ _ _

1his was an auto signal railure - see above maintenance actions

6/15/86 Approximate tnd of Refueling Outage That Sta rted 11/30/65

5/16/86 3.2 3.0 3.5 3.0 '

5/15/86 3.37 2.91 3.33 2.80

4/30/86 --- --- --- -- F004 lapped to correct excessive leakage (had railed leak test)

4/26/86 ,__ ___ __._ ___

F020 rewi red to di fferent limit switch and passed test - apparently not a

solenoid problem (?)

4/26/86 3.13 3.22 3.5 Failed

Notes: (1) for the stroke times recorded in the first five valve tests (19 values during 4/26 - 7/17/86) the mean = 3.17 and

the standard deviation = 0.27

(2) * indicates stroke times which dirrer from the above mean by more than 2 standard deviations

(3) / indicates stroke times which dirrer from the above mean by more than 3 standard deviations

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TABLE 2

CHRONOLOGICAL TABULATION Of CLOSURE STROKE TIMING FOR UNIT 1

VALVES 1-G16-F003, F004, TO19 AND F020

Date Stroke Times (Seconds) fo r Va l ves

F QR}_ ffRQ9 IO19 fy?J

1/2/88 2.81 3.16 3.20 2.90

11/2/87 2.70 2.25/ 2.16/ 1.88/

8/9/87 3.0 3.6* 3.3 3.1

6/20/87 End of Refueling Outage That Started 2/14/87

5/9/81 3.33 3.25 3.21 3.08

4/2G/87 3.80 3.34 3.46 3.28

2/5/87 2.79 3.07 3.13 2.99

11/6/87 2.87 2.80 3.15 2.76

8/5/86 2.96 3.09 3.34 3.20

5/6/86 2.18 3 . 0 *> 3.15 3.11

2/12/86 2.90 3.05 3.23 3.13

11/2/85 2.76 3.08 3.38 3.13

9/22/85 2.80 3.39 3.61* 3.53

Notes: (1) I')r the stroke times recorded in the first five valvo tests (20 values durin9 9/22/85 - 8/5/86) the mean = 3.13 and

the standaro deviation = 0.23

(2) * indicates stroke times which dirror f rom the above mean by more than 2 standard deviations

(3) / indicates stroke times which dirrer f rom the above mean by more than 3 standard deviations

_ _ _ _ _ _ - - . - _ - _ _ _ _ _ _ _ _ _ _ _ - _ _ _ _ - - _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ _ _ _ - . - _ _ - _ _ _ _ _ - -_ _ ._-.________J

- - - - - - - . -_----_--- _ _ - - - -

.

.

7

b

I

-

15

e

TABLE 3

COMPARIS0N OF STROKE TIMES OBTAINED BY FOLLOWING

PROCEDURE VERSUS CORRECT METHOD FOR

UNIT 1 VALVES 1-G16-F003, F004, F019 AND F020

Valve No. Stroke Time Measured (Seconds)

Per Procedure - (From Correct Method - (From

switch closure actuation switch closure actuation

until red light off) until green light on)

1G16-F003 1.38#, 0.96#, 1.16 2.76

1G16-F004 1.14 2.87

1G16-F019 1.16 3.02

1G16-F020 1.06 2.76

mean = 1.13 2.85

standard deviation = .05 .12

Note: # denotes the first two measurements at the start of testing.

The operator who performed the testing felt that they were not

sufficiently accurate and performed the third measurement which he

considered sati sf actory. The # values were not included in the

calculation of mean and standard deviation.

. -