ML18054B450

Responds to Violations Noted in Insp Rept 50-255/89-26. Hamstad Rept Encl.Corrective Actions:Licensee Concludes That All Instrumented Insp Technique Testing Performed at Plant in Accordance W/Plant Specific Procedures

ML18054B450
Person / Time
Site:	Palisades
Issue date:	02/06/1990
From:	BERRY K W CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML18054B451	List: ML18054B450 ML18054B452
References
NUDOCS 9002260498
Download: ML18054B450 (5)

See also: IR 05000255/1989026

Text

• • Kenneth W Berry Director * POWERING MICHIGAN'S

PROGRESS General Offices: 1945 West Parnall Road, Jackson, Ml 49201 * (517) 788-1636 February 6, 1990 Nuclear Regulatory

Commission

Document Control Desk Washington, DC 20555 DOCKET 50-255 -LICENSE DPR-20 -PALISADES

PLANT -RESPONSE TO INSPECTJON

REPORT 255/89026

NOTICE OF VIOLATION, "INSTRUMENTAL

INSPECTION

TECHNIQUE" (IIT) Nuclear Licensing

Consumers

Power Company was informed by letter dated November 2, 1989 that the ASME required hydrostatic

pressure test performed

during the 1988

outage is considered

invalid. The Hydrostatic

test requirement

was met by utilizing

the Instrumental

Inspection

Technique (IIT) an NRC approved alternative

to the ASME code specified

method. This letter requested

CPCo to evaluate its examination

procedures

and the IIT test data. If tests were confirmed

to be invalid, Consumers

was requested

to identify all ASME systems and components

subject to the hydrostatic

pressure testing requirements

of ASME Section XI which were tested using the IIT technique

and to determine

whether the affected systems could bejudged functionally

operable.

If the tests were determined

to be valid, the NRC was to be informed of the basis for this determination

and a description

of the system or component

tested and the date of the test. In addition, an inspection

report dated December 8, 1989 on the same subject identified

deficiencies

in content of and adherence

to the detailed testing procedures.

An extension

of 30 days for the required response was granted during the telephone

conference

call with DDanielson

of the NRC staff on December 21, 1989. This correspondence

addresses

specifically

the three parts to violation

255/89026.

Consumers

Power Company response regarding

the validity of the Instrumented

Inspection

Technique

tests performed

at Palisades

will be forthcoming.

Consumers

Power Company has concluded

that all IIT testing performed

at Palisades

was in accordance

with plant specific procedures

and the NRC approved RAFA Topical Report 135 (P-A) which was approved by the NRC for licensing

reference

on November 7, 1985. In addition, Consumers

Power has determined

that all affected systems are operable and fully capable of performing

their intended safety functions.

The basis for ASME Section XI Hydrostatic

Testing operability

determinations

OC0290-0254-NL04

9002260498

900206 PDR ADOCK 05000255 Q PDC A OHS EIV*RGY COMPANV

• • * * Nuclear Regulatory

Commission

Palisades

Plant Response to IR 89026 February 6,' 1990 has been documented

under Docket 50-255 License DPR-20 -Palisades

Plant dated November 13, 1989. It should be noted that Consumers

Power Company intends to perform a hydrostatic

test (or approved alternative

test) on the main steam system following

the steam generator

replacement

outage, currently

scheduled

for fall 1990. A hydrostatic

test of the auxiliary

feedwater

system suction piping will be performed

in the upcoming maintenance

outage as post modification

test requirement, per Section XI IWA-4400.

NOTICE OF VIOLATION

255/89026-lA

Interim and post verification

of channel sensitivity, considered

a prerequisite

for acoustic testing was neither performed

nor required by the procedures.

The NRC has concluded

that "The pencil-lead

break check performed

prior to testing is not considered

an acceptable

method of sensor calibration

due to the fast rise/decay

transient

as opposed to the continuous

signal procdure by a leak. Interim and post verification

of channel sensitivity

in considered

essential

in the evaluation

of test data." 2 The pencil lead break technique

uilized in the pre-test verification

of the operability

and sensitivity

of the IIT Acoustic test equipment, as required by the IIT Acoustic test procedure, is considered

an acceptable

method for this application

by ASTM Standard E-976, the Acoustic Emission Handbook and NUREG/CR-5134.

In performing

an independent

review of the IIt Acoustic test method, Dr Marvin Ramstad, University

of Denver, has concluded (See attached) "My examination

shows that the stanrlard

lead break calibration

technique

used by RAFA along with reasonable

sensor spacings does provide assurance

that leaks (with acoustic strengths

equivalent

or greater than the levels of those examined in the laboratory, in plant development

tests and in field tests to date) will be detected in the field. Current RAFA practice emphasizes

a lead break on the pipe near the base of each acoustic waveguide.

These breaks are carried out prior to the pressure test. RAFA used this data primarily

to verify the particular

channel at which the lead break was made. This approach checks the sound transmission

of: 1) the adhesive from the pipe to the waveguide;

ii) the adhesive between the waveguide

and the sensor. It also checks the sensor and acoustic measurement

system. In my opinion the data from these lead breaks also provides the information

to check the sensitivity

of the sensor to leaks located some distance form the sensor. By examining

lead break calibration

data I determined

the amplitudes

at the adjacent sensors and found them to be consistent

with the values to be expected for reasonable

sensor spacings." In regard to interim post-test

verifications

of channel sensitivity, Dr Ramstad has stated that "since the acoustic test criticality

depends on maintaining

sensitivity

throughout

the whole test. I have examined RAFA approaches

• towards assuring maintenance

of sensitivity.

Their approach has been three-fold:

use of the response to ad.i acent sensors to normal changes in plant operating

conditions;

ii) use of simulated

leak sources and OC0290-0254-NL04

• Nuclear Regulatory

Commission

Palisades

Plant Response to IR 89026 February 6, 1990 iii) in some cases

lead breaks. These approaches

are important

due to the potential

for the test conditions

to disturb the sensitivity . . There are at least three potential

things that could happen: i) temperature

rise resulting

in loss of acoustic transmission

due to an adhesive change or failure; ii) vibrations

resulting

in fracture of an adhesive bond; and iii) temperature

effects on the sensors and/or preamplifiers.

My finding indicate that the HAFA approaches

are effective

in finding extreme losses in sensitivity."*

Additionally, RAFA performs comparative

checks of all IIT Acoustic test equipment

to ensure appropriate

sensitivity

exists both before and after testing. Based upon the above, it is Consumers

Power Company's

belief that the Acoustic test procedure

did include provisions

for assuring that all prerequisites

for a,given test have been met, thereby satisfying

the requirements

of 10 CFR 50, Appendix B, Criterion

XI. NOTICE OF VIOLATION

(255/89026-lB)

The lack of a qualified, well designed relationship

between background

noise level and leak detection

sensitivity

did not permit evaluation

of the suitability

of environmental

conditions

encountered

during the test. 3 During IIT Acoustic testing, changes in environmental

conditions

affect leak detection

sensitivity

in different

ways, both negatively

and positively.

Changes in ambient temperature

during plant heat-up, which are most pronounced

in the containment

atmosphere, produce a negative affect on the order of a 1 to 2 db decrease in sensitivity.

Changes in system temperature, which affects only the waveguide-system

epoxy bond, produce a negative effect on the order of an approximately

5 db decrease in sensitivity.

The change in system temperature

does not affect the sensitivity

of acoustic sensors since the waveguides

are designed and utilized to off set the sensors from the system and dissipate

the effects of increased

temperature.

Changes in system temperature

affect leak detection

sensitivity

in a positive manner also. Data contained

in NUREG CR-5134 shows that as system temperature

increases, acoustic signals from leakage increase.

NUREG CR-5134 data also shows that acoustic signals from leakage increase with increases

in system pressure.

IIT Acoustic test data has shown that during tests performed

during plant heat-up, the background

noise level actually decreases

from that noted when the baseline data was acquired.

All IIT Acoustic test equipment

was installed, verified for operability

and operated in accordance

with the IIT Acoustic test procedure.

Therefore, for IIT Acoustic testing, changes in environmental

conditions, as a whole, actually enhance leak detection

sensitivity

rater .than degrade it. During IIT Leak Testing (that utilizing

Leak Measuring

Devices (LMD's), environmental

conditions

are not

to changes which would degrade the leak sensitivity

of the Acoustic Leak Sensing Equipment (ALSE) used. Acoustic sensors are attached to boundary valves on the test subsystems

and verified for operability

in accordance

with the IIT test procedures.

The test subsystem

boundary is Sufficient

ALSE background

data is acquired at minimal differential

pressure conditions

to ensure that the detection

of OC0290-0254-NL04

• Nuclear Regulatory

Commission

Palisades

Plant Response to .IR 89026 Febru'ary

6, 1990 increased

acoustic signals. Shortly thereafter, ALSE data is acquired at maximal differential

pressure conditions

when test pressure is achieved.

Comparison

of this data is made to aid in the location of leakage through boundary valves at test pressure conditions.

Therefore, for both types of IIT testing, the suitability

of environmental

conditions

as they affect the relation ship between background

noise levels and leak detection

sensitivity

has been addressed

both in the IIT test procedures

and in the methods used to perform the testing. Based upon the above, it is Consumers

Power Company's

belief that the IIT test procedures

did include provision

for assuring that the tests were performed

under suitable environmental

conditions, thereby satisfying

the requirements

of 10 CFR 50, Appendix B, Criterion

XI. Notice of Violation

255/89026-lC

The test procedures

did not define the acceptance

criteria and insufficient

instrumentation

was used. 4 Consumers

Power Company does not agree that the test procedures

did not define the test acceptance

criteria.

A visual examination, VT-2, as defined in ASME Section XI, Article IWA-5000, is required by RAFA Topical Report 135 (P-A) for IIT testing. This acceptance

criteria was specified

in Section 6.0 of each IIT test procedure

and a VT-2 examination

was performed

as required by each IIT test procedure

using Consumers

Power Company VT-2 examiners.

The VT-2 ations or the completed

IIT test results were reviewed by Authorized

Inspectors

from Factory Mutual Insurance

Company. Each IIT test procedure

specified

utilization

of appropriate

IIT test equipment

to the level required by RAFA. Topical Report 135 (P-A). For those tests using the IIT Leak Testing method, at least 1 Leak Measuring

Device was utilized to monitor each test boundary, and all test boundary valves were monitored

with Acoustic Leak Sensing Equipment.

For the test using the IIT Acoustic method, 5 Electro-Acoustic

Ranging units and 148 acoustic sensors were utilized to monitor the test boundary.

All IIT test equipment

was installed

and operated in accordance

with the IIT test procedures.

Based upon the above, it is Consumers

Power Company's

belief that the IIT test procedure

did incorporate

acceptance

limits and that adequate test

ation was available

and was used,

satisfying

the requirements

of 10 CFR 50, Appendix B, Criterion

XI. Li -

c

Kenneth W Berry ' Director, Nuclear Licensing

CC Administrator, Region III, USNRC NRC Resident Inspector

-Palisades

Attachment

OC0290-0254-:NL04

• • * * OC0290-0254-NL04

ATTACHMENT

1 Consumers

Power Company Palisades

Plant Docket 50-255 HAMSTAD REPORT February 6, 1990 7 Pages