IR 05000269/1987011
| ML16161A802 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 04/21/1987 |
| From: | Jape F, Whitener H, John Zeiler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML16161A801 | List: |
| References | |
| 50-269-87-11, 50-270-87-11, 50-287-87-11, NUDOCS 8704300239 | |
| Download: ML16161A802 (9) | |
Text
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.,U NITED STATES
NUCLEAR REGULATORY COMMISSION REGION 11 101 MARIETTA STREET, ATLANTA, GEORGIA 30323 Report Nos.:
50-269/87-11, 50-270/87-11, and 50-287/87-11 Licensee:
Duke Power Company 422 South Church Street Charlotte, NC 28242 Docket Nos.: 50-269, 50-270, License Nos.: DPR-38, DPR-47, and and 50-287 DPR-55 Facility Name:
Oconee 1, 2, and 3 Inspection Conducted:
March 11-19, 1987 Inspectors:
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e g H. L. Whi tener Date Signed J,
Ze-7 ate Signed Approved by:
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// J F. Jape, Section Chief Date Signe Engineering Branch Division of Reactor Safety SUMMARY Scope:
This routine, announced inspection was conducted in the areas of containment integrated leak rate testing including review of the test procedure, witnessing of the test performance and evaluation of the test result Results:
No violations or deviations were identifie PDR ADOCK 05000269 Gi PDR
REPORT DETAILS 1. Persons Contacted Licensee Employees M. Tuckman, Plant Manager
- J. Davis, Superintendent, Technical Services
- R. Bond, Performance Engineer
- K. Rohde, Test Engineer, Performance
- K. Chea, Test Engineer, Performance
- C. Harlin, Compliance Engineer
- F. Owens, Regulatory Compliance M. Geckle, Test Engineer, Performance (Catawba Facility)
R. Smith, Technical Support Group, General Office M. Hutcheson, Associate Engineer, General Office NRC Resident Inspectors J. Bryant, Senior Resident Operator L. Wert, Resident Inspector
- Attended exit interview 2. Exit Interview The inspection scope and findings were summarized on March 19, 1987, with those persons indicated in paragraph 1 above. The inspector described the areas inspected and discussed in detail the inspection finding No dissenting comments were received from the license The following new item was identified during this inspectio On new item was identified concerning the apparent malfunction of the pressure instrument during the Unit 1 integrated leak rate tes The licensee agreed to submit additional information to show that the instrument was functional subsequent to an apparent shift in the calibration of about 0.03 ps This information will be submitted by August 1, 198 The licensee did not identify as proprietary any of the materials provided to or reviewed by the inspectors during this inspectio. Licensee Action on Previous Enforcement Matters (Open) UNR 50-269/86-13-01:
This item concerns the licensee investigation as to the cause of a pressure perturbation identified in the Oconee Unit 1 Type A test data and the possible effect on the test result The Unit 1 Integrated leak Rate test report did not provide sufficient information to
evaluate the operability of the pressure instrument subsequent to the perturbation and did not provide an assessment of the leak rate based on resolution of the instrument proble The licensee will provide the additional information needed to complete the NRC review by August 1, 1987. This item remains ope. Unresolved Items Unresolved items were not identified during this inspectio. Containment Integrated Leak Rate Test (CILRT) - Unit 3 (70313) (70307)
The inspector reviewed and witnessed test activities to determine that the primary containment. integrated leak rate test was performed in accordance with the requirements of Technical Specification 4.4, Appendix J to 10 CFR 50, ANSI-N45.4 and the test procedure PT/3/A/0150/03A,
"Reactor Building Integrated Leak Rate Test."
Selected sampling of the licensee's activities which were inspected included:
(1) review of the test procedure to verify that the procedure was properly approved and conformed with the regulatory requirements; (2) observation of test performance to determine that test prerequisites were completed, special equipment was installed, instrumentation was calibrated, and appropriate data were recorded; and (3) preliminary evaluation of leakage rate test results to verify that leak rate limits were me Pertinent aspects are discussed in the following paragraph a. General Observations The inspector witnessed and reviewed portions of the test preparation, containment pressurization, temperature stabilization and data processing during the period of March 12-19, 198 The following areas were inspected:
(1) The test was conducted in accordance with an approved procedur (2) Test prerequisites selected for review were found to be complete (3) Selected plant systems required to maintain test control were found to be operationa (4) Special test instrumentation was reviewed and found to be installed and calibrate (5) Data required for the performance of the containment leak rate calculations were recorded at ten-minute interval (6)
Problems encountered during the test were described in the test event lo (7) Temperature, pressure, dew point, and flow data were recorded at ten-minute interval Data were assembled and retained for final evaluation and analysis by the license A final ILRT report will be submitted to the NR No violations or deviations were identified in this revie b. Procedure Review (70307)
The inspector reviewed portions of PT/3/A/0150/03A, "Reactor Building Integrated Leak Rate Test," to verify that test controls, valve alignments and acceptance criteria were specified. No major problems were identified; some minor adjustments were resolved with the licensee relating to clarification of test specification The licensee has identified add-on leakage in an enclosure to the procedure. The acceptance criteria in section 11 of the procedure specifies that the leak rate will be determined by mass point analysis 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 dat An exemption to Paragraph III.A.3 of Appendix J was granted to Oconee in a letter dated February 24, 1987, to H. B. Tucker from H. N. Pasti The exemption allows the use of the mass point analysis metho All other aspects of Paragraph III.A.3 remain in forc Valve alignments, specified in TT/3/A/0375/09 were not reviewed except for changes to the procedure since this procedure was reviewed in detail during a previous inspection and is reported in IE Report 50-269/84-13 and 50-287/84-1 This procedure accomplishes the venting, draining, and alignment for the Type A tes The inspector also reviewed PT/3/A/0150/03B,
"Reactor Building Integrated Leak Rate Prerequisite Test."
This procedure verified that the containment liner weld channels were vented to the containment pressur The inspector concluded that the licensee had acceptable procedures for performance of the integrated leak rate tes c. Integrated Leak Rate Test (ILRT) Performance (70313)
(1) Method A 24-hour containment integrated (Type A) leak rate test and a four hour supplemental leak rate test were performed on the Unit 3 primary containment at a reduced pressure of 31 psi Mass point-linear regression analysis was used by the licensee to determine the leak rate and 95% upper confidence limit (UCL).
Leakage analysis was based on data taken at 10 minute intervals for a minimum of 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (2) Test Description After completion of the containment inspection, the containment was pressurized to the leakage rate test pressure, of 31.4 psi Significant test events extracted from the test log were as follows:
Date Time Event 3/16 0410 Pressurization of the containment was initiate Pressurization of the containment was secured at 45.6 psi Temperature stabilization was initiate Leakage surveys were performed and the only significant leakage identified is through the airlock inner door handle packin No repairs were mad Containment air temperature met the stabilization criteri The airlock was pressurized to 28 psig (containment at 31 psig) to expedite stabilization of the leak rat The inner door leakage was about 15 pounds per hour which contributed significantly to the leak rat The start time for the Type A test was declare Bubble test on outer airlock door shows no leakag /17 0013 RTD 17 is errati Volume fraction reassigned to RTD 1 /18 0257 Type A test was terminate The leak rate for a period of 29.97 hours0.00112 days <br />0.0269 hours <br />1.603836e-4 weeks <br />3.69085e-5 months <br /> was 0.119 wt% per da Imposed leak rate established at 7 scf Verification test was initiate Verification test was terminate Post test reactor building inspection showed no apparent damag (3) Test Results - Unit 3 (a) Type A Test The allowable leakage (Lt) for Oconee Unit 3 is 0.176 wt.%
per da Therefore, the integrated leak rate test leakage limit of 0.75 Lt as required by Appendix J is 0.132 wt.%
per da The licensee's test results met the acceptance criteria for mass point analysis as shown below:
the values are expressed as weight percent per day for a 24-hour test perio Mass Point Lt (allowable leakage)
7.177 075 L (test acceptance limit)
0.1320 Ltm (1culated leakage)
0.1007 UCL (95% upper confidence limit)
0.1055 The inspector calculated weighted averages for containment temperature, pressure and vapor pressure using the weighting factors and individual sensor data for a sample of data sets to verify agreement with the weighted averages generated by the licensee's computer program. Subsequently, the weighted averages generated by the licensee's program were used by the inspector to calculate mass, leak rate, and the 95% upper confidence leak rate. The inspector's calculations agreed with the licensee's calculation (b) Supplemental Test Appendix J requires that a supplemental test be performed to verify the accuracy of the Type A test and the ability of the CILRT instrumentation to measure a change in leak rat An acceptable supplemental test method is described in Appendix C of ANSI-N45.4-1972, as follows:
A known leak rate (Lo)
is imposed on the containment and the measured composite leak rate (Lc)
must equal, within +/-0.25L the sum of the measured Type A leak rate (Ltm) pls the known leak rate (Lo).
The acceptance criteria is expressed as:
Lo + Ltm - 0.25 L < Lc < Lo + Ltm + 0.25 L t
t A 4.68-hour supplemental test was performed by the imposed leak rate method described in Appendix C to ANSI-N45-4-1972 using the mass point analysis technique to determine L The following values in units of wt.% per day were obtained:
Mass Point Ltm 0.1007 Lc 0.2463 Lo 0.1699 0.25Lt 0.044 Using the above values, Lc must fall within the limits in wt.% as follows:
Mass Point Upper Limit 0.3146 Lc 0,?463 Lower Limit 0.2266 As indicated, Lc is within the specified limits for the mass point analysis techniqu. Other Areas Inspected Relative to Leak Rate Testing a. Computer Leak Rate Program The licensee has upgraded the data acquisition system to provide adequate resolution of the state-of-the-art instrumentation input to the computer. A benchmark test was used to verify operability of the system. The inspector obtained the benchmark test data and processed it through the NRC CILRT 2 (11-4-86) test progra The NRC program calculated the same results as the licensees progra The inspector also obtained and processed several sets of raw data from the current leak rate test and obtained the same averaged results as the license The inspector concluded that there were no unresolved questions related to data processin b. Pressurization of the Personnel Airlock
.During the stabilization period, the licensee identified a large leak path through the door handle packing of the airlock inner doo The leakage was estimated to be about one-half of L and had a significant effect on the apparent containment leakag De to the large volume of the airlock, it was estimated that the leakage would affect the
apparent containment leak rate for many hours. To expedite measure ment of actual containment leakage, the licensee pressurized the airlock through the local leak rate test connection to 28 psig, 3 psi below the containment pressur The inspector reviewed this situation and determined that the Type A test result was not adversely affected for reasons as follows:
(1) The Type A test is a single barrier test. If the outer door was leaktight, the inner door leak would not be seen as containment leakage once the airlock becomes pressurized to containment pressur Further, any leakage through the outer door would still be eviden (2) A full pressure local leak rate test performed on the airlock just before the Type A test showed no leakage through potential leakage paths in the outer door when bubble tested. The leakage was noted during this test but was thought to be leaking into containment through the equalizing valve in the inner door which is expected to seal with containment pressur (3) Rapid pressurization of the'airlock would tend to unseat rather than seal the outer doo c. Advancing the Test Start Time The licensee performed a Type A leak rate measurement from 2049 hours0.0237 days <br />0.569 hours <br />0.00339 weeks <br />7.796445e-4 months <br /> on March 16, 1987 to 0258 hours0.00299 days <br />0.0717 hours <br />4.265873e-4 weeks <br />9.8169e-5 months <br /> on March 18, 1987, about 30 hour3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> The leak rate and 95% upper confidence limit (UCL)
for this period was 0.118 and 0.123 wt.% per day, respectivel These values are within the acceptance criteria of 0.75 L (0.132 wt.% per day).
In that containment stabilization at Oconeetypically takes about 12 to 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br />, the leak rate was still decreasing when the test was started after a six-hour stabilization period. The licensee extended the test to 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> in order to advance the start time to 0240 hours0.00278 days <br />0.0667 hours <br />3.968254e-4 weeks <br />9.132e-5 months <br /> on March 17, 1987. Excluding the first six hours of rapidly changing leak rates yielded a 24-hour test with a leak rate and 95% UCL of 0.101 and 0.105 wt.% per day, respectivel These values met the limits of the verification tes The actual leak rate over the last six hours of the test was in the range of 0.06 to 0.07 wt. per da These values also meet the verification test limit The inspector concluded that advancing the start time did not represent manipulation of the data in order to pass the tes d. As Found Type A Leak Rate The licensee's program for controlling the "as found" leak rate was reviewed to determine that control was establishe Control is accomplished through the established maintenance control The isolation barriers are identified to the operations personne If maintenance on one of these barriers is requested, operations will
verify with the performance group that the required leak testing is completed before releasing the system for maintenanc The established local leak rate test procedures have a status blank to indicate whether a test is an "as found" or "as left" tes The licensee had not completed the analysis of the data but indicated that no excessive leakage through both isolation barriers in a leak path were identifie The "as found" Type A test result will be reviewed in the Leak Rate Test Report submitted to the Commission.