ML18046B374

Reactor Containment Bldg Integrated Leakage Rate Test

ML18046B374
Person / Time
Site:	Palisades
Issue date:	02/28/1982
From:	CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
To:
Shared Package
ML18046B373	List: ML18046B372 ML18046B374
References
11, NUDOCS 8203260299
Download: ML18046B374 (14)

Text

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CONSUMERS POWER COMPANY PALISADES NUCLEAR PLANT SPECIAL REPORr NO. 11 RE:ACTO:t COi'lTAINI~NT BUILDI!{Z INTIDRATED LEAKAGE RAT.2; T~T DOCKET NO. 50-255 LICENSE NO. DPR-20 Prepared by:

CONSUMEP.S POWER COMPANY FEBRUARY l~b2 r 820326o299 020323

. PDR ADOCK 05000255 p

PDR

PALISADES REACTOR CONTAINMi:NT BUILDING INTEGRATZD LEAKAGE RATE TEST REPORT CONTE:ITS 1.0 Summery 1.1 History...............................*.............

1 1.2 Results........................................,....

2 2.0 Discussion 2.1 Analysis Techniques................................

2.2 Date Acquisition.............................. *......

2.3 Contai:u:ient Condition~..............................

Figure 1 Containment Iv'.ass..........................

Figure 2 Containme~t Parame~ers....................

5 b

9 3.0 Conclusion........*......................................

10 4.c References............................................... 10 5.0 Attachments

1.0

SUMMARY

1.1 HISTORY The Reactor Containment Building at Consumers Power Company's Palisades Nuclear Plant, which was designed and erected by Bechtel Power Corpora-tion, completed its initial preoperational leakage rate tests in May of 1970.

Bechtel conducted two tests:

Peak pressure test of 55 psig and a reduced pressure test of 28 psig.

The results of these two tests are given in a report prepared by Bechtel entitlecl, "Integrated Leak Rate Test of the Reactor Containment Building, Palisades Nuclear Plant, Consumers Power Compa.nY, dated July 30, 1970."

The first postoperational leakage rate test was conducted by Consumers Power Company personnel with Bechtel representatives in late April of 1974, at a reduced test pressure of 28 psig.

The test was the subject of a special report entitled, "Reactor Containment Building Integrated Leak Rate Test 1974.".

The second postoperational leakage rate test was conducted solely by Consumers Power Company personnel in March of'. 1970 at a reduced test pressure of 25 psig.

The test was the subject of a special report entitled, "Reactor Containment Building Integrated Leak Rate Test lSITb."

The nominal measured leakage rate was -0.00708 weight%/day with a one sided 95% approximate upper confidence limit of 0.00195 weight$/day.

The maximum allowable.test leakage rate in accordance with Reference 6 was 0.0559 weight%/day.

During the external survey of containment penetrations at 14 psig, during imtiai pressiirization, a containment leak was ide.ntified.

The measured leakage rate was 6o.3 staruiard liters. per minute (SLM)* at 14 psig (98.4 SLM at the actual test pressure of 31.0 psig).

An Allemite grease fittiz.ig on an isolation valve was replaced.

In accordance* with the reporting requirements of Reference 5, the 98.4 SLM leakage rate was added t~ the "as found" leakage rate of -0.00708 weight%/day.

The resulting leakage rate was 0.09242 weight%/day.

-l-

lberesults of these tests are summarized in the table belowe TEST DATE May 1970 April 1974 March 1978 INTEGRATED LEAK RATE TEST RESULTS 24-HOUR HOLD TEST LEAK RATE (55psig) 0.0048 wt1./day (28psig) 0.0233 wt%/day (28psig) 0.0342 wt1./day (28psig)

(As Found) -0.00708 wt1./day (28psig)

(Resultant) 0.09242 wt1./day

SUMMARY

APPROXIMATE UPPER 95'7.

CONFIDENCE LIMIT 0.0436 wt"l./day 0.00195 wt'7o/day Pl.ANT TECH. SPECS.

0.0514 wt'7./day 0.0559 wt'7o/day l.2 RESULTS To fulfill the requirel!Ents of References 5, a Containment Integrated Leak Rate Test (CILRT) began with containment pressurization on November 15, lYEll and concluded with containment depressurization on November lb, 19fl,1.

The reduced test pressure requirement for minimum containment pressure of 2b psig was maintained during the hold test.

From the 24-hour hold test data, a calculated nominal leakage rate of 0.0326 weight %/day with a one sided 95% approximate upper confidence limit of 0.0349 weight %/day of contained dry air mass was calc\\J.lated.. Asswr.ing a containment pressure of 26 psig, the maximum allowable leakage rate is 0.0713 weight °/a/day. ' Refere*nce '5 also *reqtd.res tnat the leakage rate cannot exceed 75% of the allowable leakage rate or 0.053; weight %/day before resumption of power operation.

This criterion was also met, therefore the Palisades Plant was able to resume power operation without repairing any containment penetrations and *reperforming the CILR'.I'.

A verification test was conducted following the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> hold test by imposing a 0.052 weight%/day leakage rate on the containment.

The imposed leakage rate plus the leakage rate measured during the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> hold test was 0.0869 weight%/day.

A calculated nominal leakage rate of 0.0832 weight %/day of contained dry air mass was obtained using the measured data. This value meets the requirements of Reference 5,Section III.A.3.b, and thus confirms the CILRl' hold test~ results.

The results of the local leak rate tests fulfilled the requirements of Reference 5,Section III.c.3, a~er necessary repairs were made on pene-trations which showed excessive leakage in the as found conditions.

The "service air", "safety injection tank drain", and the "containment sump drain" penetrations accounted for the majority of the before-maintenance leakage.

An analysis and summary of the Type B and C tests can be found in Attachment A of this report.

2.O DISCUSSIO~*i 2.l ANALYSIS TECHNIQUES The weighting factors used to calculate the average containment air temperat'l.µ'e, have been calculated based on the number of sensors within a sub-volume.

A temperature profile of the cont.ainment was taken prior to the ILRr to check the appropriateness of the calculated weighting factors.

The assigned weighting factors of a few temperature sensors in small volumes were revised as a result of the measured temperature profile.

The containment vapor pressure is computed by converting the FOXBORO de~

point temperature sensor (Dewcel) readings to vapor pressure readings through the use of the ASNE: steam tables for water and applying the appropriate weighting factors.

This containment vapor pressure is subtracted from the absolute pressure to give the containment dry air partial pressure. - The -

partial pressure of dry air and the weighted average containment temperature are then used to calculate the leakage rate in weight % per day.

The absolute method of determining the leakage rate was used for this test and measurements were recorded every fifteen (15) minutes.

The leakage rate was computed using the mass point analysis method which is endorsed by Reference 4.

In the mass point method of analysis, data from an absolute system is reduced to a contained mass of dry air by application of the ideal gas law.

The test data consists of a time series. of independent values of contained air mass. If the assumption is made that the leakage rate is constant with time, the data lends itself to.analysis by the method of linear least squares.

The slope of this line re~resents the rate of change of air mass with respect to time, which is the leakage rate.

Because of its independent nature, a measurement error will result in only one bad data point and not materially affect the test results. Although no data was rejected in this test, the data rejection criteria found in Appendix D of Reference 4 was used by the computer program to characterize the calculated lea.kage rates.

2.2 DATA ACQUISITION The previous two CILRT' s have showed difficulty in interpreting the data.

Possible causes included placement of temperature meas-urement sensors, the weighting factors used to calculate the average containment air temperature, the accuracy of the dry bulb and dew point temperature measuring instrume:r~s and the resolution of the readout devices, data recording techniques and the possfoli ty of in leakage to the containment. during the test. Since the CILRT conducted in 19(0, significant changes have been made to assure ~hat satisfactory contair:iment leek rate test date will be obtained.

The changes which have been made for the 19bl CILRT are discussed below.

The addition of six (6) resistance temperature detectors (RTD's) to the measurement system brings the total to twenty-six (26) Rl'D's located within the containment.

The addition of four (4) Dewcels to the measurement system brings the total to ten (10) Dewcels located within the containment.

The we.ighting factors used to calculate the average containment air temperaiure have been calculated basetj on the number of sensors within* a sub-volume a:1d a temperature profile of the containment which was taken prior to the ILRI'.

Representative coverage of the entire containment can be expec~ed with the sensor layout.

The maximum weighting factors were 9. 74% for a Rl'D (after an adjustment was made to the weighting factors following the loss of one RrD during pressurization) end 20% for a Dewcel.

The sensitivit/ of the RTD's and Dewcels is within the requirements of Reference 4, Section 4.3.1.

The calculated Instrument Selection Guide (ISG) for the instrumentation used during the test, met the requirements of Reference 4 Section 4.J.2.

The ISG, which was recalculated due to the loss of one temperature sensor and one pressure gauge, also met these requirements.

D6ta is collected by the ILRr psnel purchased from Volumetrics (model 1462~)

and transferred to the PDPll/03 minicomputer.

After receiving the da~a, the minicomputer program performs the functions listed below:

1.

Reduces raw data into weighted average tetr.peratures, vapor pressures, and containment pressure necessary for use in the leakage rate calcula-tions.

2.

Calculates the leakage rate in weight'i{i/day using the mass point analysis method.

3.

Determines the approximate ~5% upper confidence limit of the leakage rate using the methods described in Reference 4, Appendix B.

• 4.

Calculates the data outlier and the appropriate rejection level according to the criteria of.Reference 4, Appendix D.

5.

Provides plots of individual test parameters as well as containment average temperature, pressure, vapor pressure, and mass as a function of time.

A listing containing all of the measured data has been filed with the ILRr test procedure (Reference 7).

2. 3 CONI'AINME~rr CONDITIONS The average containment temperature fulfilled the stabilization criterion of Reference 4 Section 5.3.1.3 four (4) hours after pressurization was __

completed.

Since the ILRT data acquisition system allowed periodic calcu-lations of the leakage rate to be determined during the first few hours of the test, the obtained data was analyzed and the results were reviewed by the testing personnel.

The calculated leakage rate wu decreasing as a function of time, therefore, the calculated containment mass data has oeen reviewed to determine when stabilization was achieved. Justification for and extended stabilization period is also required by the NRC inspection report (Reference 8).

The calcul.ated containme!lt mass has been plotted as a dotted line in Figure l with a spline curve fit overlay.

The spline method applies a cubic function with continuous second derivatives to the actual test data a:id draws a smooth line through the data (reference 9).

As can be seen, the containment atmosphere was not stabilized until approximately 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> after the air compressors were shut down.

The contain-mel:l.t mass plot initially di_splays an oscHlatory motion pattern. It has a component with a decreasing amplitude and a period of approximately 4~ hours.

This condition was caused by a rapid pressurization rate.

After this component diminished, the contallml.ent mass variations became much more random.

The average containment parameters have also been plotted to show the containment conditions (Figure 2). Based on this evaluation, it is considered that the leakage rate measured after a 15~ hour stabiliza-tion period most accurately reflects the actual containment leakage rate.

Therefore, the hold test portion of this leakage rate test has 'bee:i declared to start at 320/22:24:5~.

Using the above surtirig time, leakage rates were determined for several hold test duration intervals. The results of these calculations are shown in the.following Table:

Hold Test Duration 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> 12 16 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> HOLD TEST DURATION

SUMMARY

Fitted Leakage Rate 0.02i-:~t%7d.iy--

0.031

_0.033 0.033 wta/o/day Upper 95%

Confidence Limit cLo3I wt~/d-ay

• 0.037 0.037 0.0.35 wt%/day The resul.ts of this anal/sis indicates that the new equipment employed to perform this leakage rate test is capable of determining the containment leakage rate with a hold test of less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

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c CJ 381350-381300 381250 381200 N 381150 T

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A s s l.. B s FIGUHH: 1 PALISADES 1981 CILRT 32 311

35.

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FIGURZ 2 CONTAINMENT PARAMETERS

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If the actual test pressure of 30 psig is used in determining the maximum allowable leakage rate, the acceptance criteria for resumption of power operation is 0.0554 weight %/day *. A calculated nominal leakage rate of 0.0511 weight %/day with a one sided 95% approximate upper confidence limit of 0.0539 weight %/day is calculated fOr a 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> hold test starting four hours after the air compressors were shut down.

Therefore, the Palisades Plant actually completed a successful 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> hold test after a staoalization period of' only four hours.

3.0 CONCLUSION

3.1 The Palisades containment satisfied the acceptance criteria for the integrated leakage rate test.

3.2 The verification flow rate results verified the hold test results.

3.3 The calculated ISG (after the loss of one RI'D and one pressure gauge) fulfilled the requirements of' Reference 5.

3.4 The after ma.intenance results of' the local "leak rate tests meet the requirements of.Reference 5 Section III.c.3.

4. 0 REFERENCES

1. Bechtel Report, "Integrated Leak Rate Test of the Reactor Containment Building, Palisades Nuclear Plant, Consumer.s Power Company, July 30,.

19/0."

2.

Consumers Power Company Special Report No. 6, "Reactor Containment Building Integrated Leak Rate Test, 1974."

3.

Consumers Power Company, Special Report No. 10, "Reactor Containment Building Integrated Leak Rate Test, 1978."

4.

ANSI/ANS 56.8"'.1901 .American Nati_ol'.lal Standard Containment System Leakage Testing Requirements."

5.

10CFR part 50 Appendix J.

6.

Palisades Technical Specifications.

7.

Palisades 1981 CILRT Test Procedure RI'-36.

8.

I~RC Region III Inspection Report No. 50-255/61-26.

S:/.

SAS/GRAPH User's Guide, SAS Institute, 1981 Edition PF'-13-16.

5. 0 ATTACHMENT A

l.

Type B and Type C Test Results.

ATTACHMENT A TYPE B AND TYPE C TEST RESULTS This attachment is included in accordance with the requirements of 10CFR50, Appendix J, to report and provide a summary analysis of the results of type Band C tests.

The results of each type Band C test performed since the last integrated leakage rate test are contained in Table A-1.

As indicated by Taole A-1, the leakage rate following repairs was within the acceptance criterion. A summary of the repairs which were made is as "follows:

1. During the 197Sl-19c0 Refueling Outage, the total as-found local leakage rate test result was 442,570 cc/min.

This was due largely to four penetrations.

The leakage rate for three of these four pene-

. trat*ions; #11 (Condensate to Shield Cooling Surge Tank); #14 (cc,; In),

and #33 (Safety Injection Tank Drain) was corrected by repairing the internals for the defective penetration valves.

To upgrade the fourth penetrations, Pen #2b (Containment Air Sample), a modifica-c.ion was performed to change the configuration by adding new penetration valves.

2.

In November 1~60 it was determ~ned that the check valve for penetration

1. 14 was allowing leakage past its seat.

The leakage caused the total leakage rate for all penetrations to be greater than the Technical Specification acceptance criteria of 6~,200 cc/min.

The check valve was cut out of the line and replaced by another check valve with an improved design.

3.

The as found local leakage rate test result for the 1961 Refueling Outage was 186,660 cc/min.

The three penetrations with excessive leakage were penetration #10 (Service Air to Containment), penetration #33 (Safety Injection Tank Drain), and penetration #52 (Containment Sump Drain).

To correct the leakage for penetrations #33 and #52 the internals for the defective valves were repaired.

For penetration #10 ne*,.,. -

replacement valves were installed.

In addition, a modification for penetration #33 is being planned for the next refueling outage which

~

~.

I*~-..

TABLE A-1 Summary of Type B and Type C Tests Performed Since Last ILRT (1978)

Test S~quence No.

Date As Found LLRT Penetrations Tested Total (cc/min)

XIIIa April 12, 1978 XIIIb July 18, 1978 XIIIc October 4, 1978 XIIId February 1, 1979 XIIIe

.July 17, 1979 XIV September 1979 to May 1980 XIVa

• .July 8, 1980 XIVb & c November 1980 XIVd December 10, 1980 XIVe.

May 21, 1981 XIVf June 11, 1981 XIVg July 24, 1981 XIVh August 13, 1981 XIV August 1981 to Nover:ii::>er 1981 November 15 to November 18, 1981 Equipment Hatch N/A Personnel Lock, 17,575.2 Escape Lock Purge Air Exhaust, 22,730.9 Purge AiT Supply, Equipment Hatch Penetrations #37 & 41, 37,030.5 South Electrical Pen, Personnel Air Lock, Escape Air Lock Personnel Air Lock, 25,611.4 Escape Air Lock All Penetratio.ns 442 5 570 (Refueling Outage)

Penetration 1137 Personnel Air Lock, 127,825.6 Escape Air Lock, Penetration #14, Equipment Hatch Penetration 040 35,599.5 Penetration #40 35,913.3 Personnel Air Lock, 26,290.3 Escape Air Lock

. Penetration #40, 33,~70.9 Equipment*Hatch Equipment Hatch

.. N/ A All 186' 859.7 (Refueling Outage)

ILRT Perfonned XIVa November/December Personnel Air Lock, 47,803.3

• Penetrations #2.7, 3'7, 41, 10, Equipment Hatch As Left LLR7 Total (cc/r:.:.-::

19,688.9 17,575.2 22,730.9 27,671.7 25,611.4 29,650 28,476.1 35,597.6 35,599.5 35' 913. 3 26,290.3 29,108.S 29,068.9 47,803.3 31,902.0 NOTE:

Technical Specific~tion Acceptance Criteria is a maximum combined leak rate of 65,200 cc/min for all penetrations.

would replace five isolation valves with one, thus upgrading the penetration configuration.

Evaluation of the Type B and Type C test results indicate that a small number of penetrations account for a large amount of leakage.

In each case, the leakage has been corrected by appropriate repe:.ir or replacement.

In a few instances, modifications have oeen rr~de or are planned to upgrade the penetration configuration by replacin6 multiple isola~ion valves by.a single *valve.

In all cases, the local leakage rate tests*

fulfilled the requirements of Reference 5 after repairs were perfor~ed.

A related area in leakage testing concerns the leakage measurement from the recirculation heat removal system outside of containment.

In the December lSfbl test, a total leakage of 44.35 ml per minute was measured, which was well whhin the technical specification allowa::;le of 0. 2 gpm ( "(56 ml per minute).