IR 05000259/1979038
| ML18024B451 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 01/08/1980 |
| From: | Brooks E, Upright C, Whitener H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18024B447 | List: |
| References | |
| 50-259-79-38, 50-260-79-38, 50-296-79-38, NUDOCS 8004020263 | |
| Download: ML18024B451 (10) | |
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UNITEDSTATES NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTAST., N.W., SUITE 3100 ATLANTA,GEORGIA 30303 Report Nos. 50-259/79-38, 50-260/79-38 and 50-296/79-38 Licensee:
Tennessee Valley Authority 500A Chestnut Street Chattanooga, Tennessee 37401 Facility Name:
Browns Ferry Docket Nos. 50-259, 50-260 and 50-296 License Nos.
DPR-33, DPR-52 and DPR-68 Inspection at Browns Ferry site near Athens, Alabama Inspectors:
H. L. Whitener p'te igned E. H. Brooks Approved by:
C.
.
right, Act g Section Chief, RONS Branch Date Signed b 6'o at Signed SUMMARY Inspection on November 19-23, 1979 Areas Inspected This routine, announced inspection involved 82 inspector-hours onsite in the areas of witnessing preparations and performance of the containment integrated leak rate test and local leak rate testing, drywell inspection of hydraulic shock arrestors, follow-up on previously identified open and unresolved items and general inspection in certain areas of the reactor building and drywell.
Results Of the four areas inspected, no items of noncompliance or deviations were identi-fied in three areas; one item of noncompliance was found in one area.
Infraction:
the use of a temporary CRD hatch cover during the integrated leak rate test (para-graph 6.b).
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DETAIIS 1.
Persons Contacted Licensee Employees
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Abercrombie, Plant Superintendent Harness, Assistant Plant Superintendent Jones, Outage Director Swindell, Assistant Outage Director Ferguson, Assistant Outage Director White, CILRT Director Clark, CILRT Director Butcher, CILRT Coordinator Bishop, Programmer
'Primo, CILRT Engineer Haney, Assistant Supervisor of Maintenance Thigpen, Assistant Mechanical/Maintenance Supervisor Jackson, Assistant Electrical Maintenance Supervisor Other licensee employees'ontacted during this inspection included one shift engineer and two operators.
NRC Resident Inspector
~"J.
Chase
+Attended exit interview.
2.
Exit Interview The inspection scope and findings were summarized on November 23, 1979, with those persons indicated in Paragraph 1 above and in a subsequent telephone conversation with Mr. Abercrombie on December 19, 1979.
3.
Licensee Action on Previous Inspection Findings Not inspected.
4.
Unresolved Items Unresolved items are matters about which more information is required to determine whether they are acceptable or may involve noncompliance or deviations.
One new unresolved item identified during this inspection is discussed in Paragraph '
The inspector witnessed the performance of the Primary Containment Integrated Leak Rate Test (CILRT) on Unit 3 to determine that the test was conducted in accordance with the requirements of 10 CFR 50, Appendix J, ANSI N45.4, FSAR
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Section 5, and test procedure SI4.7.A.2 (Primary Containment Integrated Ieak Rate Test).
Selected sampling of the licensee's activities which were inspected included:
(1) review of SI4.7.A.2 to verify that the test procedure was properly approved and conformed to regulatory requirements; (2) observation of test performance to determine test prerequisites were completed, special equipment was installed and calibrated and that appropriate data were recorded and analyzed; and, (3) preliminary evaluation of leakage rate test results.
Pertinent aspects of the test are discussed in the following subparagraphs.
a.
General Observations The inspector witnessed and/or reviewed portions of the test preparation, containment pressurization, temperature stabilization, leak chasing, and data processing in the period November 19-23.
The following items were noted:
The test was conducted in accordance wi,th an approved procedure maintained at the test control center.
Changes to the procedure were documented.
(2).
A sampling of test prerequisites was
~ reviewed and found to be complete.
(3)
A sampling of plant systems required to maintain test control ups reviewed and found to be in service.
(4)
A sampling of penetration valve alignments was observed and found to be aligned per procedure.
(5)
Special test instrumentation was reviewed and found to be'nstalled and calibrated.
Instrument checks were performed just prior to the test.
(6)
Data required for the performance of the containment leak rate calculation were recorded at 10 minute intervals.
Data were assembled and retained for final analysis and evaluation.
(7)
Problems encountered during the test were described in the test event log.
(8)
Final analysis of the leak rate data will be performed by the licensee's ILRT Groups, and will be reported in the test report to the Office of Nuclear Reactor Regulation (NRR).
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b.
Test Description and Results A reduced pressure (40 PSIA)
containment integrated leak rate test (type A)
was performed using a linear regression analysis of the absolute mass point data to calculate the leakage rate.
Test para-meters of temperature, pressure, vapor pressure and volume changes were recorded and inputted to the computer at 10 minute intervals.
The pressurization and test sequence were as follows:
Date 11/21 Hour 1603-2130 Comment Pressurize primary containment to 40.2961 PSIA (25.8 PSIG).
11/21 11/22 2130-2400 0000-1800 Stabilization period--leak rate in excess of allowable limit but on a steadily decreasing trend.
11/22 1800-2100 Repressurize containment to ensure minimum test pressure is not exceeded.
11/23 0204 Start IIRT 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> run.
11/23 0424 Correct the position of unit valve 21-1452 to open position and include in procedure.
Restart ILRT 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> run.
11/23 0824 Leak rate appears to be stabilizing with-in acceptable limits but still exhibiting a decreasing trend--measuring slightly negative leak rate believed to be due to low pressure front and rapid temperature changes.
11/23 11/24 1230-1230 Official 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> ILRT run.
ll/24 2000 to 11/25 0100 5 hour5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br /> verification run At 1200 hours0.0139 days <br />0.333 hours <br />0.00198 weeks <br />4.566e-4 months <br /> on November 23, 1979, the measured parameters were indicating essentially stable but slightly negative leak rate of the order of -0.01$.
The inspectors'alculation using a one volume model without volume change correction confirmed the negative leak 'rate.
The licensee subsequently found that the volume correction due to torus water level changes was incorrectly computed.
After correction of the volume computation, the calculated leak rate'was 0.03$ per day which is well within the acceptable limit of 1.06$ per day.
The licensee reported that agreement between the verification test and measured leak rate was 4'/, which is well within the allowable 25/.
-4-a.
Secondary Containment Integrity During an inspection tour of Unit 3 on November 20, 1979, the inspectors observed that both the inner and outer reactor building airlock doors were opened at the same time.
This resulted in a momentary loss of secondary containment integrity at the same time the primary containment airlock doors were open.
The plant was in cold shutdown in preparation for performing the containment integrated leak rate test.
This matter was discussed with licensee mechanical and electrical maintenance personnel and the problem appears twofold as follows:
(1)
Mechanical-A guide pin internal to the door latching mechanism is too short and will sometimes permit the latch to bind and fail to lock.
(2)
Electrical-Design of the door interlock activating mechanism is such that if both the inner and outer doors are pulled at the same time the interlock will not actuate in time to prevent both doors from opening.
The licensee took immediate action to ensure that the airlock interlocks were functioning mechanically.
A 30 day event report will be submitted to the NRC specifying action taken or to be taken to prevent recurrence.
This matter remains open for follow-up inspection and applies to all three Units (259/260/296/79-38-01).
b.
Control Rod Drive Hatch The inspectors observed that the containment was pressurized through a
special attachment installed on the control rod (CRD) hatch pentration.
This attachment consists of a special CRD hatch cover containing a
inch penetration with an isolation valve and a hose connection.
After pressurizing containment the isolation valve is closed and the pressuri-zing line from the compressors is removed from the attachment during the integrated leakage rate measurement.
When the ILRT is completed and the containment depressurized the special CRD hatch cover is removed and the permanent CRD hatch cover used in normal reactor operation is installed and locally leak tested between double seals.
The inspector expressed a concern that the permanent CRD hatch cover is not tested under type A test conditions and advised licensee manage-ment that this matter was unresolved.
On further review the inspector concluded that testing without the normal cover plate on the CRD hatch containment penetration during the overall integrated leakage rate test (type A) does not meet the intent of Appendix J to 10 'CFR 50.
Specifically,Section II.E. and II.F. of Appendix J state, in part, that the type A test is intended to measure the overall integrated leakage rate through all potential leakage paths including components which penetrate containment.
The use of a
temporary hatch cover during the type A test was identified as an item of noncompliance (50-296/79-38-03).
Chain Hoist Failure The inspector observed the repair activity related to the RHR heat exchanger tube bundle drop that occurred October 7, 1979 as a result of supporting chain failure.
Discussions with the licensee revealed that although a procedure for 0~aration, Maintenance,
~Testis, and
~lns ection of Nuclear Plant Cranes and Hoists DPM No. N74M1 (Revision dated July 23, 1979)
does exist; it has not been implemented.
The procedure was reviewed by the inspector.
Recorded visual inspection of lifting slings or chains expected to be used during the shift is required by the procedure.
It is questionable as to whether visual inspection of the chains used to lift the RHR tube bundle might have prevented the accidental drop since the tube bundle had been supported by the chain for three days prior to failure.
No requirement for load testing liftingslings or chains is included in the procedure.
Unresolved Item:
This matter of implementation of inspection and/or testing of lifting slings and chains is considered to be an unresolved item subject to subsequent review by NRC (50-296/79-38-02).
Snubbers During the tour of Unit 3 drywell, the inspectors performed an inspec-tion of a number of hydraulic and mechanical snubbers.
One problem was identified concerning slightly loose pipe clamp bolts on relief valve 71A tail pipe.
The licensee stated that these bolts would be tightened and similar clamps reinspected to verify tightness of bolt