IR 05000259/1991020
| ML18033B726 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/30/1991 |
| From: | Blake J, Lenahan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18033B725 | List: |
| References | |
| 50-259-91-20, 50-260-91-20, 50-296-91-20, NUDOCS 9106110174 | |
| Download: ML18033B726 (10) | |
Text
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UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTASTREET, N.W.
ATLANTA,GEORGIA 30323 Report Nos.:
50-259/91-20, 50-260/91-20, and 50-296/91-20 Licensee:
Tennessee Valley Authority 6N 38A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Docket Nos.:
50-259, 50-260 and 50-296 I
Facility Name:
'Browns Ferry 1, 2, -and
License Nos.:
DPR-33, DPR-52, and DPR-68 Inspection C
d..
May 13-17, 1991 Inspector han Date Si ned Approv d by.
J ke, Chief a erials Process Section Engineering Branch Division of Reactor Safety Date Signed SUMMARY Scope:
Thi's special, announced inspection was conducted in the areas of the Unit 2 piping thermal expansion program, piping vibration monitoring program, and results of the system 10-year hydrostatic test.
Results:
In the areas inspected, violations or deviations were not identified.
The hydrostatic test data indicated that the test results complied with ASME Section Xl requirements.
The thermal expansion test procedures were explicit and well stated for control of test activities, except for the attached drawings which were not adequate to use in performing field walkdown inspections.
A weakness was identified in the implementation of the initial walkdown inspection performed when the reactor system temperature was at ambient conditions.
Test personnel (system engineers)
performing the walkdown inspection failed to identify numerous potential interference to thermal growth.
This problem may be attributed to the inadequate drawings used for the walkdown or a failure of the systems engineers to understand test requirements (paragraph 3).
'Pi06110174 910531 PDR ADDCK 05000259 G
REPORT DETAILS 1.
Persons Contacted Licensee Employees
- S. Austin, Compliance Engineer
- M. Bajestani, Technical Support Operations
- J. Bynum, Vice President, Nuclear Operations
- M. Keck, Systems Engineer, Technical Support J. Kiker, Systems Engineer, Technical Support
- J. Lewis, Supervisory Engineer, Technical Support L. Myers, Plant Manager K. Pinson, Systems Engineer, Technical Support
- I. Zeringue, Vice President, Browns Ferry Operation Other licensee employees contacted during this inspection included
'ngineers, technicians, and administrative personnel.
Other Organizations
- J. Bowen, Field Engineer, General Electric Company (GE)
NRC Resident Inspectors
- C. A. Patterson, Senior Resident Inspector
- E; Christnot, Resident Inspector
~Attended exit interview 2.
Review of 10-year Reactor Pressure Vessel/Main Steam System Hydrostatic Test Data (73055)
The inspector reviewed the 10-year reactor pressure vessel and main steam system hydrostatic test data.
Acceptance criteria utilized by the inspector appear in Technical Specification 4.6.6. 1 and the American Society of Mechanical Engineers (ASME)
Code, Section Xl, l974 Edition through Summer 1975 Addenda.
The inspector previously reviewed the test procedure, Surveillance Instruction 2-SI-3.3.1.8, ASME Section Xl Hydrostatic Pressure Testing of the Reactor Pressure Vessel and Main Steam Piping, and observed the test during an inspection documented in NRC Inspection Report Nos.
50-259, 50-260, and 50-296/91-15.
The following data was reviewed by the inspector:
a.
The Hydrostatic Test Log b.
Valve lineup data sheets, Post-test Configuration, for selected systems
c.
The completed, signed-off test procedure (2-SI-3.3. 1.8)
d.
Test pressure data e.
Results of gC inspections performed during hydrostatic test, document on ASME VT-2 Visual Exam Data Sheets.
These data sheets document leakage which occurred during the test.
All leakage was through mechanical joints, gaskets, or valve packing; there were no through-wall leaks or leaks through welded joints.
f.
Documentation that temporary supports and pins had been removed (Step 7.43 of test procedure).
The inspector also walked down portions of the main steam system and verified that the temporary supports and pins had been removed.
The. hydrostatic test was completed on April 9, 1991.
Work Requests have been written to repair the identified leaks.
These areas will be reinspected by the licensee during reactor startup to ascertain the leaks have been properly repaired.
Wi-thin the areas inspected, violations or deviations were not identified.
3.
Thermal Expansion Test - Unit 2 (70370)
The licensee has committed to NRC to conduct a piping thermal expansion test as part of the Unit 2 restart test program.
The purpose of this test is to identify any interference associated with piping thermal movements resulting from modifications installed since the original unit startup testing was completed.
During a previous inspection (See Inspection Report Nos.
50-259, 50-260 and 50-296/91-15)
the inspector reviewed Technical Instruction 2-TI-90, System Thermal Expansion.
The procedure contains
'instructions for performance of the piping thermal expansion test during heatup to normal operating temperature, and return to ambient temperatures.
The inspector attended a briefing conducted by the test engineer for the system engineers who were to perform the piping inspection to identify potential interference and record snubber and spring can setting.
This briefing was conducted prior to the start of the walkdown inspection at ambient temperature for the purpose of reviewing walkdown inspection requirements and to answer questions regarding inspection assignments.
- The test engineer referred inspection personnel to Appendix C of procedure 2-TI-190.
This appendix provides specific examination of the thermal expansion walkdowns.
Appendix C contains guidance for identification of misalignment and/or binding of pipe supports, required clearance, and information or properly obtaining position measurements for snubbers and spring cans.
After the system engineers completed their initial walkdown inspections at ambient conditions, the inspector, accompanied by a
GE field engineer, walked down various piping systems in the drywell.
During the walkdown,
~
the inspector identified numerous potential i'nterferences to thermal movement on the feedwater and main steam piping.
Review of the walkdown data sheets (Appendix F to TI-190) disclosed that several of these potential interferences had not been identified by licensee personnel.
These interferences were documented on Test Deficiency. Evaluation/
Resolution Reports and forwarded to nuclear engineering design personnel for evaluation.
The design evaluations involved calculation of the predicted piping movements.
These calculations indicated that the piping would move in a direction which-would not result in any interaction between piping and any other plant feature as a result of thermal movements.
A few potential thermal interferences were identified which required minor modifications to mirror insulation installed on the piping.
Based on review of-the engi'neering evaluation, the inspector concluded that the licensee's program for identification and evaluation of potential thermal, interference was adequate.
However, the inspector identified the failure of licensee personnel to identify several potential thermal interferences during the ambient walkdowns as a
weakness.
Further discussions with licensee engineers disclosed that some of the original field data which documented potential interferences was insufficient for use by design engineers in performing their evaluations.
This made it necessary for licensee personnel to make additional entries into the drywell to obtain the information (measurements, sketches, etc.) required to evaluate the potential interferences.
The precise location of the interference was also difficult to determine using the drawings in Appendix A of the procedure.
these drawings are flow diagrams which indicate the limits of the inspection boundaries.
However, unlike piping isometric drawings, location of specific points on the piping is not feasible using the flow diagrams.
Licensee engineers indicated that they will consider using isometric drawings for future walkdown inspections.
The licensee also plans to add other pe'rsonnel to the walkdown teams, specifically design engineers to ascertain that adequate data is obtained on the walkdown inspections to preclude the need to make additional entries into the drywell when the reactor is at power.
The inspector also examined portions of the high pressure core injection (HPCI) piping and the residual heat removal (RHR) piping in the reactor building, outside of the drywell, but within the boundaries of the thermal expansion test.
Within the areas inspected, violations or deviations were not identified.
4.
Snubber Surveillance Program - Units 1-3 (70370)
The inspector examined records which document the service life of snubber seals.
The licensee is in the process of updating their service life records and are reverifying that the Unit hydraulic snubbers have seals within the 10-year service life period.
The records available for review were either snubber maintenance (rebuilding)
data sheets, or vendor's
It
certification record for new snubbers which have been installed as replacements in the plant.
Within the areas inspection, violations or deviations were not identified.
5.
Piping Vibration gualification Test - Unit 2 (70370)
The inspector reviewed Post-modification Test Instruction PMT-201, Piping Vibration gualification Testing.
This procedure specifies prerequisites, precautions, instructions, and acceptance criteria for performance of the piping vibration test.
The purpose of the test is to observe piping and supports under specific system operating conditions to detect possible symptoms which could result in excessive wear, maintenance, or loosening of components.
Inspections will be conducted by the licensee to detect symptoms such as pump cavitation, check valve chatter, bouncing or sliding of pipe within support gaps, impacting movement in pinned connections, and large relative movements between branch lines and process pipe.
Systems to be inspected include main steam, reactor water cleanup, reactor core isolation cooling, HPCI and RHR.
The test boundaries are shown on isometric drawings included in Appendix F of the test procedure.
Within the areas inspected, violations or deviations were not identified.
6.
Exit Interview The inspection scope and results were summarized on May 17, 1991, with those persons indicated in paragraph 1.
The inspector described the areas inspected and discussed in detail the inspection results.
Proprietary information is not contained in this report,.
Dissenting comments were not received from the license I I