IR 05000261/1982009

IE Insp Rept 50-261/82-09 on 820301-07.No Noncompliance Noted.Major Areas Inspected:Containment Integrated Leak Rate Testing

ML20052B944
Person / Time
Site:	Robinson
Issue date:	04/06/1982
From:	Falconer D, Jape F, Whitner H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
To:
Shared Package
ML20052B941	List: IR 05000261/1982009 ML20052B940
References
50-261-82-09, 50-261-82-9, NUDOCS 8205040170
Download: ML20052B944 (7)

Text

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h UNITED STATES

1 NUCLEAR REGULATORY COMMISSION

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E REGION 11 Q

101 MARIETTA ST., N.W., SUITE 3100

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ATLANTA, GEORGIA 30303 Report No. 50-261/82-09 Licensee:

Carolina Power and Light Company 411 Fayetteville Street Raleigh, NC 27602 Facility Name:

H. B. Robinson 2 Docket No. 50-261 License No. DPR-23 Inspection at H. B. Robinson Plant site near Hartsville, South Carolina Inspectors: NI h

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H.~ L. Whitener

'Date Signed R d_tdi 5 ~ / L /

4l'zhz D. P. Falconer ~ ~

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Date Signed Approved by: M[

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F. Jape, Section Chief

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Date Signed Engineering Insoection Branch Division of Engineering and Technical Programs SUMMARY Inspection on March 1-7, 1982 Areas Inspected This routine, announced inspection involved 138 inspector-hours on site in the area of containment integrated leak rate testing.

Results Of the area inspected, no violations or deviations were identified.

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REPORT DETAILS 1.

. Persons Contacted Licensee Employees

• R. Starkey, Plant General Manager

' *J. Curley, Manager, Technical Support

• S. Zimmerman, Director Planning and Scheduling S. Crocker, M; nager, E&RC M. Page, Engineering Supevisor G. Chappel, Project Engineer W.' Farmer, Engineer, Test Project Coordinator F. Gilman, Senior-Specialist, Regulatory Compliance

• C. Wright, Specialist, Regulatory Compliance P. Snavely, Control Operator Other Organizations

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Gilbert Associates

• R. Shirk, Engineering Supervisor

- R. Casey, Engineering Specialist J. Blessing, Engineering Specialist M. Brown, Engineering Technician NRC Resident Inspector S. Weise

• Attended exit interview 2.

Exit Interview The inspection scope and findings were summarized on. March 5,1982, with those persons indicated in paragraph 1 above and. tar a' telephone conversa-tion with the Plant General Manager on March 10, 1982. At'the time of the exit on March 5, the integrated leak rate test (ILRT) was in progress. The inspector-stated that the findings at the conclusion of the ILRT would be discussed with licensee management onsite or by telephone.

Other matters discussed at the exit interview:

a.

Containment Supply and Exhaust Purge Valves The licensee has committed to not cycle the containment supply and exhaust purge valves - when containment integrity - is required.

The valves may be cycled when containment integrity is required provided the valves have been demonstrated to seat leak tight within technical m

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i-specification allowable leakage limits. If the valves are cycled, the l-as found leakage must be determined and the ILRT leak rate adjusted (Refer to paragraph 6 for details).

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b.

ILRT Supplemental Test When the' ILRT supplemental test was terminated on March 7, the mea-I sured composite leak rate did not agree with the limits specified by Appendix J to 10 CFR 50.

This was believed to be due to an. error in flow meter calibration. The inspector requested an _ opportunity - to I

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review the corrected data when available. Until an acceptable supple-

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mental test is. demonstrated, ILRT results are not acceptable (for

detail refer to paragraph 5.b.3).

This matter. was identified as i

unresolved.

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. Valve Alignment Two valves were identified in incorrect positions. This did not affect the ILRT results in that valve positions were corrected prior to the i

second 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test. The factors which lead to incorrect valve posi-

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tions will be reviewed by the Resident Inspector (Refer to paragraph 5.a for details).

3.

Licensee Action on Previous Inspection Findings Not inspected.

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4.

Unresolved Items

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j Unresolved items are. matters about which more information is required to determine whether they are acceptable or may involve violations or devia-

'tions. New unresolved items identified during this inspection are discussed

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in paragraph 5.b.3.

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5.

Containment Integrated Leak Rate Test i

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Region - Specialists in conjunction with the Resident Inspector witnessed I

performance _ of the primary containment integrated ' leak rate test'(ILRT)_

to determine that the test was conducted in accordance with the require-

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1ments of _ Appendix J toL10 CFR 50, ANSI N45.4, FSAR Section 5, ILRT proce-

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dure and Technical Specification.

Selected sampling ' of the licensee's

. activities which were inspected included:

(1) review of. the test proce-dure to verify-that the procedure was properly' approved and conformed to i-regulatory requirements; (2) observation of test performance to determine

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test prerequisites were completed, special equipment was installed and

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i calibrated and that appropriate data were recorded and analyzed; ~and (3)

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preliminary evaluation of leakage rate ' test results to-verify that' leak

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rate limits were met. Pertinent aspects of.the test are discussed in the

following paragraphs.

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General Observations -

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The inspectors witnessed and reviewed portions of the test prepara-tion, containment pressurization, temperature stabilization and data processing during the period of March 1-7, 1982. Within this area the inspectors' findings were as follows:

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(1) The test was. conducted in accordance with an approved procedure maintained at the test control center (2) A sampling of test prerequisites was reviewed and found to be completed.

(3) A sampling of plant systems required to maintain test control was

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reviewed and found to be completed.

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(4) Special instrumentation was reviewed and found to be installed and

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calibrated.

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(5) Venting and draining of specific systems were reviewed and found

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to be complete.

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(6) Data required for the performance of the containment leak rate

calculations were recorded at 30 minute intervals.

(7) Problems encountered during the test were described in the test

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event log.

(8) Pressurized gas sources were reviewed for proper isolation and

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venting to preclude in-leakage or interference of cut-leakage

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through containment isolation valves.

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(9) Procedure valve alignment was reviewed against system drawings to

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verify correct boundary alignment.

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(10) A sampling of valve positions were observed to verify conformance to procedure valve alignment.

I (11) Temperature, pressure, dew point and flow data were recorded at 30

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minute intervals. Data were assembled and retained for final

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evaluation and analysis by the licensee's consult' ant, Gilbert

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Associates. A final ILRT report will be submitted to the Office of Nuclear Reactor Regulation.

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With the exception of item (8) and (10), no problems were identified

during review of the above items.

Regarding items (8) and (10), the

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inspectors found that the nitrogen pressure line to the accumulators

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was not depressurized and vented to the atmosphere.

This apparently

resulted from turning the regulator the wrong direction when attempting

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to isolate this line. As a result, 1080 psi nitrogen pressure was r

applied to isolation valve SI-855. Also, a vent valve outside con-e tainment (PS-989E) on the accumulator sample line was closed where

. the procedure required the valve to be open.

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'These items did not affect the ILRT leak rate results since they were-corrected prior to the second 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> leak rate test.

The factors

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which resulted 'in the errors are being pursued by the Resident

Inspector.

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Integrated Leak Rate Test performance (1) Method the containment leak rate was determined by the mass point analysis and linear regression techniques on -a minimum of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of mass data recorded at 30 minute intervals. Containment pressure was one half accident pressure (21 psig). A statistical

95's upper confidence limit (UCL) was calculated.

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l (2) Test Description and Results The required four hour temperature stabilization was successfully completed at 9:40 a.m.,

March 4; however, air absorption and redistribution. continued to yield a high leak rate for several

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hours. At 3:40 p.m., March 4 a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> data run was initiated.

The first 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> of data indicated a leak rate of about 0.02 wt.% per day which is well below the allowable leak rate of 0.042 wt.?? per day. About 4:00 a.m. March 5 the leak rate increased.

An excessive leak rate was experienced over the next twelve hours.

The licensee located several minor leaks but was unable to locate or explain the excessive leakage. At 3:40 p.m., March 5 the exces-

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sive leakage stopped and a second 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> run was initiated. This test was successfully concluded at 3:40 p.m., March 6.

Measured

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values were as follows:

Ltm, measured leakage rate 0.02 wt.?; per day 95?4 confidence interval 0.007 wt.*4'per day UCL, Ltm + 95*4 confidence 0.027 wt.*4 per day interval 0.75 Lt, acceptance limit 0.042 wt.*4 per day

The UCL is well within the acceptance limit.

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(3) Supplemental Test-Appendix J. requires ' that a supplemental test be performed to F-verify the accuracy of the Type A test and the ability of the ILRT instrumentation to measure a change in leak rate. A known leak

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rate (Lo) is imposed on the containment and the measured com-posite leak rate (Lc) must equal, within 0.25 Lt, the sum of-the measured leak rate (Ltm) plus the known leak rate (Lo).

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-The acceptance criteria is expressed as:

Lo + Ltm - 0.25 Lt sLc slo + Ltm + 0.25 Lt.

i Results from the supplemental test were as follows:

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Lo

= 0.052 wt.f4 per day l

Ltm

= 0.02 wt.?; per day

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= 0.014 wt.*s per day Lc

= 0.12 wt.?; per day i

Substituting these values in the acceptance criteria shows that Lc does not meet the specified limits of 0.05*s s0.12?s s0.086?s.

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r Licensee personnel stated that the flow meter calibration appeared I

to be in error.

Previous calibrations of the same meter would t

yield a Lc which would meet the acceptance limits. The licensee

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terminated the supplemental test at 12:40 a.m., March 7.

Prior to leaving the plant the inspector advised licensee personnel that until a successful supplemental test is demonstrated, the Type A i-test is not considered acceptable. This matter was identified as unresolved item (261/82-09-01).

6.

Containment Purge Valves Paragraph III.A.1(b) of Appendix J to 10 CFR 50, requires that closure of I

containment isolation valves shall be accomplished by normal methods without

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any subsequent adjustment. Af ter the last closure of the containment supply and exhaust purge valves, seat adjustments were made to certain of these i

valves to reduce leakage.

Due to history of purge valve leakage, the licensee did not wish to cycle the purge valves prior to the ILRT.

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inspectors reviewed this matter with licensee representatives and several

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points were identified relative to control of purge valve leakage at the plant as follows:

a.

The supply and exhaust containment purge valves are part of a valve leakage monitoring system. During plant operation the volume between

the inboard and outboard purge valves is maintained at a pressure slightly higher than accident pressure by a continuous monitoring i

penetration pressurization system (PPS).

This system enables the licensee to identify purge valve leakage in about 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after' valve closure.

It takes 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to repressurize -the volume between the valves and detect leakage on the PPS flow meters.

b.

Records show a history of seat leakage after purge valve closure. On 8 occasions in 1981 work orders were issued to adjust purge valve seats in order to prevent leakage. Control room logsheets showed that on 3

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1 occasions in February 1982, leakage which exceeded the flow meter range

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on the PPS "A" header required valve seat adjustments. Thus, although frequent leakage has occurred, the PPS allows identification and correction of the leakage.

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- Purge valve leakage problems were made worse by the interim require-ments limitin'g valve opening to 30 degrees. When valves are qualified for 70 opening the licensee believes the ' greater spring generated I

closure force will result-in better seating.

d.

' Although use of the purge valves at power is not prohibited, it is the licensee's policy to not open purge valves at power.

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The inspector concluded that failure to cycle the purge valves prior to the ILRT was. acceptable under certain conditions.

These conditions - were presented to the licensee as the following-t

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a.

The purge valves will not be cycled when containment integrity is i

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required.

The valves may be cycled where containment integrity is

not required providing that a leak tight seat is verified after

closure and before entering a mode requiring containment integrity.

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b.

The purge valves may be placed into. service when containment integrity

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is required providing that adequate corrective action has been imple-

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mented and the valves demonstrated to seat leak tight (within allowable

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leakage limits).

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If the option b. is chosen, the as found leakage must be determined for the purge valves and added to the ILRT results to determine the as found con-tainment leakage.

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The licensee informed the Resident Ir.spector that at this time the purge -

valves will not be used when containment integrity is required.

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