IR 05000155/1985020

Insp Rept 50-155/85-20 on 851023-1106.No Violations or Deviations Identified.Major Areas Inspected:Containment Integrated Leak Rate Test & Results,Tech Specs & Local Leak Rate Test & Results

ML20138Q203
Person / Time
Site:	Big Rock Point File:Consumers Energy icon.png
Issue date:	11/21/1985
From:	Guldemond W, Hare S NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
To:
Shared Package
ML20138Q195	List: IR 05000155/1985020 ML20138Q192
References
50-155-85-20, NUDOCS 8512270089
Download: ML20138Q203 (9)

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U.S. NUCLEAR REGULATORY COMMISSION

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REGION III

N'eport No. 50-155/85020 Docket No. 50-155 License No. DPR-06 l Licerisee: Consumers Power Company 212 West Michigan Avenue Jackson, MI 49102 Facility Name: Big Rock Point Nuclear Plant Inspection At: Charlevoix, MI

!nspection Conduc ed: er 23 through November 6, 1985 Inspector:

/ M.~Hare*/ 4f /// /

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Approved By: G. Gu dem , Chi // / 4'S perational/P ograms Date

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Inspection Summary Inspection on October 23 through November 6, 1985 (Report No. 50-155/85020(DRS))

Areas Inspected: Routine, announced inspection, by a region based inspector of the Containment Integrated Leak Rate Test (CILRT); CILRT results; Technical Specifications;-local leak rate test results; and as found CILRT result The-inspection involved 56 inspector-hours onsite by one NRC inspector, including 38 inspector-hours onsite during offshift An additional 6 inspector hours were expended in the Region III offic Results: . Of the five areas inspected, no violations or deviations were identifie PDR ADOCK 05000155

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DETAILS 1. Persons Contacted Consumers Power Company

• D. Hoffman, Plant Superintendent

• G. Withrow, Maintenance Superintendent

• R. Alexander, Technical Engineer

• L. Manshor, Quality Assurance Superintendent W. Trubilowicz, Operation Superintendent

• D. Mogenburg, Engineering Supervisor

• J. Toskey, Technical Engineer 0. Desnoyer, Corporate Headquarters Engineer U.S. NRC S. Guthrie, Senior Resident Inspector The inspector also contacted and interviewed other licensee personnel during this inspectio * Denotes personnel present at the exit teleconference on November 6, 198 . Containment Integrated Leak Rate Test (CILRT) Procedure Review The inspector reviewed Revision 16 of Procedure TV-06 entitled

" Containment Integrated Leak Rate Test" for technical adequacy and conformance with regulatory requirements. With the exception of the following open items, the procedure appeared adequat (1) Step 3.12 allows local leak rate test corrections to be made to the Type A test results. The inspector noted that this is the only place in the procedure that refers to correcting the Type A test results and is vague in that it does not specify what type of correction (s) is to be made. The inspector stated that provisions should be made in the procedure to; monitor all water levels in containment and assign a penalty to the Type A test results if water levels increase during the test (e.g.-steam drum);

monitor the pressure of any unvented pressurized vessel within containment and take a penalty if pressures decrease during the test (e.g.-control rod drive accumulators); take penalties for penetrations that should, but are not, exposed to the Type A test pressur This considered an open item (155/85020-01(DRS))

pending inspector review of the revised CILRT procedur :

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(2) The inspector noted that the procedure has no data rejection criteria to determine if a sensor is faulty or if whole data sets are ba The inspector stated that the only time sensors / data sets may be rejected is if they satisfy these rejection criteria or a strong physical reason exists to do so (e.g.-sensors output goes to zero/ data is invalidated due to inadvertent pumping of air into containment). This is considered an open item (155/85020-02(DRS)) pending the inspector's review of the revised CILRT procedur (3) Step 5.33 pertaining to the use of the Integrated Leak Rate Monitoring system specified that data is taken at 15 minute intervals and after any 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of successive data, the data are compiled and a final integrated leakage rate will be compute This step implies that if a test took 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> or greater to obtain satisfactory results, it would be acceptable to use the last 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of data for the official test result This interpretation was confirmed when the inspector questioned licensee personnel involved in the tes The inspector informed the licensee that this is not acceptable and that all data must be used unless a legitimate reason (e.g. data rejection criteria, physical anomality or inadvertent change in test conditions)

exists not to use certain data. This is considered an open item (155/85020-03(DRS)) pending the inspector's review of the revised CILRT procedur (4) The inspector noted that the procedure specified that the size of the superimposed leak for the purpose of the supplemental verification test be 0.75 L This is contrary to the require-ment of ANSI N45.4-1972 and is not consictent with the NRC position that the quantity of gas bled from containment be between 0.75 and 1.25 La. The inspector ensured that the size of the superimposed leak for this test was greater than 0.75 L This is considered an open item (155/85020-04(DRS)) pending the inspector's review of the revised CILRT procedur b. Sunimary of Appendix J Requirements To ensure the licensee's understanding of Appendix J requirements the inspector had numerous discussions with licensee personnel during the course of the inspectio The following is a summary of the issues discussed with the license (1) Whenever penetration configurations during a CILRT deviate from the ideal, the results of LLRTs for such penetrations must be added as a penalty to the CILRT results at the 95% confidence level. An acceptable penetration leakage penalty is determined using the minimum pathway methodology. This methodology is defined as the minimum leakage value that can be quantified through a penetration leakage path (e.g., the smallest leakage of two valves in series).

This assumes no single active failure of redundant leakage barrier Additionally, any increase in containment sump or Steam Drum

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level during the course of the CILRT must be taken as a penalty to the CILRT results. If penalties exist, they must be added (subtraction is never permitted) to the upper confidence level of the CILRT result (2) The Type A test length must be 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> or lenger to use the mass point method of data reduction. If tests of less than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> are planned, the Bechtel Topical Report, BN-TOP-1, must be followed in its entirety except for any Section which conflicts with Appendix J or Technical Specification requirements. For either methodology, the acceptance criterion is that the measured leakage at the 95% upper confidence limit must be less than 75%

of the maximum allowable leak rate for the pressure at which the test was performe (3) For the supplemental test, the size of the superimposed leak rate must be between 0.75 and 1.25 times the maximum allowable leak rate La or Lt. The supplemental test must be of sufficient duration to demonstrate the accuracy of the tes The NRC looks for the results stabilizing within the acceptance criteria, not just being within the acceptance criteria. Whenever the BN-TOP-1 methodology is being used, the length of the supplemental test cannot be less than approximately one half the length of the CILRT and the BN-TOP-1 method of data reduction must be use (4) An acceptable method for determining if the sum of Type B and C tests exceeds the 0.60 La Appendix J and Big Rock Technical

, Specification limits is to utilize the " maximum pathway leakage" metho The maximum pathway methodology as it applies to Big Rock is discussed further in Paraijraph 5.0. This methodology is defined as the maximum leakage value that can be quantified through a penetration leakage path (e.g., the larger, not total, leakage of two valves in series). This assumes a single active failure of the better of two leakage barriers in series when performing Type B or C tes (5) Future periodic Type A, B, and C test must include both as found and as left result In order to perform repairs prior to a Type A test, an exemption from Appendix J requirements should be obtained from NRR. The exemption should state how the licensee plans to determine the as found conditio.. of the containment since local leak rate repairs are being performed prior to the CILRT. An acceptable method is to commit to add any improvements in leakage rates which are the result of repairs or adjustments (ras) using the " minimum pathway leakage" methodology. This further discussed in Paragraph .

. . . Instrumentation The inspector reviewed the instrumentation calibration data associated with performing the CILRT. A multipoint calibration of all the

. instrumentation was performed. Correction values were generated based on the difference between measurements from an NBS verified standard and actual measurements. All corrections were placed as an array or equation into the CILRT compute The following instrumentation was used in the CILRT:

Tyge Quantity RTDs 20 Flow meters 2 Pressure Gauges 2 Dewcells 10 Valve Lineup Verificat:on Valve lineups for the following systems were verified correct to ensure that no fluid could enter the containment atmosphere and that proper venting was provided or penalties taken:

• Treated Waste System

• Reactor and Fuel Pit Drain

• Core Spray and Post Incident System

• Demineralized Water

• Instrument Air

• Service Air

• Containment Vents

• Air Compressors for CILRT Containment Survey Requirements This inspector reviewed " Instrumentation Recommendations for Integrated Leak Rate Testing at Big Rock Point" to determine if the document satisfied the requirements of ANSI N45.4-1972 for temperature averag The inspector noted that this document, coupled with the uniform containment temperatures encountered during the performance of the Type A and Supplemental test is indicative of a containment model which does marginally satisfy the requirements of ANSI N45.4-197 Problems encountered during the supplemental test believed to

be due to diurnal effects (localized heating of the containment shell due to sunshine) should have been picked up by the instrumentation

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system but was not. The inspector stated that some effort should be made to measure the air space temperature close to the shell of the containment to monitor and compensate for these diurnal effects.

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.. . Test Witnessing The licensee began pressurization on October 25, 1985. After the containment was declared stable, the measured leakage phase of the test began the morning of October 25. After a successful 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> test, a. supplemental leak was imposed and the supplemental verifica-tion test began. Due to the aforementioned diurnal, effects the supplemental verification test took 10.25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> to stabilize within

, the acceptance criterio Following the successful supplemental l verification test, preparations began for the depressurization of the containment structur No violations oi deviations were identifie . Test Results CILRT Data Evaluation Th'e inspector independently monitored and evaluated leak rate data to verify the licensee's calculation of leak rat There was agreement between the inspector's and licensee's leak rate calculations as indicated in the following summary (units are in weight percent per day):

Measurement Licensee Inspector Leakage rate calculated (Ltm) 0.09154 0.09154 Ltm at 95% confidence level 0.09587 0.09588 Appendix J acceptance criterion at the 95% confidence level = 0.75 Lt

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= 0.75 (0.3569) = 0.2677 weight percent per day. As indicated above, the adjusted Lam at the 95% confidence level was less than the Appendix J acceptance criterio Supplemental Test Data Evaluation After the satisfactory completion of the Type A test on October 26, a known leakage of 0.2788 weight percent per day was induced. The inspector independently calculated the supplemental induced flow rate and independently monitored and evaluated leak rate data to verify the licensee's calculation of the supplemental leak rat There was excellent agreement between the inspector's and licensee's leak rate calculations as indicated in the following summary (units are in weight percent per day):

Measurement Licensee Inspector Calculated leakage (Lc) rate 0.2918 .2919 during supplemental test Induced leakage rate (Lo)= 3.45 SCFM

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.. ~. l Appendix J acceptance criterion: Lo+Ltm-0.25La<Lc<Lo+Ltm+0.25La, (0.2811<Lc<0.4595). As indicated above, the supplemental test results satisfied the requirements of 10 CFR Part 50, Appendix No violations or deviations were identifie . Review of Technical Specifications The inspector reviewed the Big Rock Point Technical Specifications for conformance with 10 CFR 50, Appendix J, requirements and NRC policy regarding Type A, B and C testing. The' inspector found the Technical Specifications consistent with current requirement No violations or deviations were identifie . Local Leak Rate Results Review The inspector reviewed the most recent local leak rate test (LLRT) results for acceptability and conformance with regulatory requirements. The results appeared to be indicative of adequate corrective action for excessively leaking isolation valves. For clarification, the inspector noted to the licensee that the maximum' pathway methodology explained in paragraph 2.b is the correct methodology to add locals to determine

. Technical Specification 3.7(a) and Appendix J complianc No violations or deviations were identifie x 6. As Found Condition of CILRT Results -

The "as found" condition of the containment is the condition at the beginning of an outage prior to any repairs or adjustments (ras) to the containment boundar CFR 50, Appendix J, Paragraph III.A.1 requires that during the period between the initiation of.'thiscontainment inspection and the performance of the Type A test, no repairs or

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adjustments shall be made so that the containment can be tested in as close to the "as is" condition as practica ANSI N45.4-1972, Paragraph 4.2 requires "For retesting, an initial record proof test shall be' conducted at time periods and pressures established by the responsible organization, before any preparatory repairs are made- This will disclose the normal state of repair of the containment structure,and4a record of the results shall be retained." The NRC's position on the " initial record proof test" requirement is that it may be waived provided the Type A test results are back corrected for all ras to the containment boundary made prior to the performance of the Type A tes If ras are made to the containment boundary prior to the Type A test, local leak rate tests must be performed to detirmine the leakage rates before-and after the ras. The as found Type A test results can then be obtained by adding the difference between the affected path leakages before and after ras to the overall Type:A test results, The as found leakage rate results are required and carry the same reporting requirements as the other Type A and Supplemental test results. The correct methodolog@ for back correcting the Type A test results, as

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_, described in section 2.b(5) of this report, is the minimum pathclay methodolog .

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To insure the licensee's understanding of how to calculate an as found penalty the inspector and a member of the licensee's staff went over in detail the methods to determine an as found penalty. The following is a summary of what was discussed:

' ' ' (1) In the case where individual leak rates are assigned to two valves in series, the penetration through leakage would simply be the smaller of-the two valves' leak rate (2) In the case where a leak rate is obtained by pressurizing between

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two isolation valves and the individual valve's leakage is not

< quantified, the as found penetration through leakage would be 50 percent of the measured leakage and the as left penetration through leakage would be zero (this assumes one or both of the repaired valves leaks zero).

(3) In the case where a leak rate is obtained by pressurizing between two isolation valves and only one valve is repaired, the as found penetra-tion through leakage would conservatively be the final measured leak rate and the as left penetration through leakage would be zero (this assumes the repaired valve leaks zero).

The inspector stated that the licensee should incorporate the above methodology into a procedure to ensure the correct interpretation of the requirements in the future. This is considered an open item (155/85020-05(DRS)) pending the inspector's review of the procedur The inspector reviewed the quantified as found and as left local leak rate test results to determine an as found pensity to apply to this outage's

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Type A test result The following is a summary of the as found containment leak rate for this outage (units are in weight percent per day):

Measurement Penalties incurred due 0.03419 to quantified repairs or adjustments prior to the CILRT As found Type A test result 0.13006 Appendix J, Acceptance Criteria for the as found condition of the containment = 0.75 Lt = 0.2677 wt %/ day. As indicated above the as found containment leakage rate was less than the Appendix J acceptance criterio No violations or deviations were identifie ,

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7. - OpenItems -

Open items are matter which have been discussed with the licensee, which will be reviewed further by the inspector, and which involve some action on the part-of the NRC or licensee or bot Open items disclosed during this inspection'are discussed in Paragraph 2.a and . ' Exit Interview l

- The inspector had a teleconference with licensee. representatives listed in Paragraph 1 on November 6, 1985, and summarized the scope and findings of the inspection. The inspector discussed the likely informational content of the inspection report with regard to documents or processes reviewed by the inspector during the inspection. The licensee did not identify any such documents or processes as proprietar l

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