IR 05000259/1991015
| ML18033B705 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 05/10/1991 |
| From: | Blake J, Lenahan J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18033B704 | List: |
| References | |
| 50-259-91-15, 50-260-91-15, 50-296-91-15, NUDOCS 9105210030 | |
| Download: ML18033B705 (13) | |
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J UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTASTREET, N.W.
ATLANTA,GEORGIA 30323 Report Nos.:
50-259/91-15, 50-260/91-15, and 50-296/91-15 Licensee:
Tennessee Valley Authority 6N 38A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Docket Nos.:
50-259, 50-260 and 50-296 Facility Name:
Browns Ferry 1, 2, and
Inspection Conducted:
April 2-8, 991 Inspector:
e a
Approved by:
a, ef Materi s
rocess Section Engine ring Branch Division of Reactor Safety License Nos.:
DPR-33, DPR-52, and DPR-68 ate
>gned tn j/
ate igned SUMMARY Scope:
This special, announced inspection was conducted in the areas of tensioning of the Unit 2 reactor vessel head, the 10-year reactor system, hydrostatic test, the snubber surveillance program, and the Unit 2 thermal expansion program.
Results:
In the areas inspected, violations or deviations were not identified.
The activities inspected demonstrated constant evidence of prior planning and assignment of priorities.
Procedures were explicit and well-stated for control of activities.
Decision making was at a level which ensured adequate management review.
Approach to resolution of technical issues was sound, thorough and conservative.
One weakness identified was the lack of available records which would readily demonstrate the snubber seal life program, paragraph 5.c.
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REPORT DETAILS Persons Contacted Licensee Employees
- S. Austin, Compliance Engineer N. Bajestani, Technical Support Manager H. Hatton, Operations Superintendent
- R. Helton, Mechanical Engineer, Technical Support
- M. Herrell, Operations Manager J. Kiker, Mechanical Engineer Systems J. Lewis, Supervisory Engineer, Technical Support
- L. Meyers, Plant Manager
- J. Shaw, Engineering Supervisor, Technical Support C.
Wages, Maintenance Other licensee employees contacted during this inspection included engineers, operators, mechanics, and administrative personnel.
NRC Resident Inspectors
- C. A. Patterson, Senior Resident Inspector
- E. Christnot, Resident Inspector
- Attended exit interview Tensioning of Reactor Pressure Vessel Head Studs (71711)
The inspector reviewed procedures which control work activities related to tensioning of the reactor vessel head studs, and witnessed portions of the stud tensioning.
Acceptance criteria utilized by the inspector appear in Technical Specification 3/4/6.A.
The inspector examined Section 10.12 of Mechanical Maintenance Instruction (NMI) number MMI-1, Vessel and Cavity Reactor Disassembly and Reassembly.
This section of the procedure contains work instructions, precautions, and requirements for tensioning of the reactor vessel head.
The inspector also examined Surveillance Instruction 2-SI-4.6.A.5, RPV Temperature Monitoring with Head Tensioned (Cold Condition).
This procedure contains surveillance requirements to ensure the reactor vessel temperatures are within limits specified in TS 3/4.6.A.5 when the reactor vessel head studs are tensioned or when stud tensioning is in progress.
The inspector witnessed tensioning of sequence numbers 21, 22, and 23 in the second pass loading of the stud tensioning for head closure.
The inspector verified the hydrostatic pump pressure was 5200 psi as specified in procedure NMI-1, and that the stud tensioning was accomplished in the proper orde The inspector also verified reactor vessel temperatures, recorded using procedure 2-SI-4.6.A.5, were within limits specified in TS 3/4.6.A.5.
The temperature data was recorded at hourly intervals.
Within the areas inspected, violation or deviation were not identified.
3.
Observation of the Reactor Pressure Vessel and Main Steam Systems, Ten Year'ydrostatic Test {73053)
The inspector examined procedures, work activities, and reviewed test data relating to the Unit 2 reactor pressure vessel and main steam systems hydrostatic test.
The test boundaries included ASME Section III, Class I and Class 2 piping and components.
Acceptance criteria utilized by the inspecto~
appear in Technical Specification 4.6.G.3.,
and the American Society of Mechanical Engineers (ASME)
Code,Section XI, 1974 Edition through Summer 1975 Addenda.
a.
Review of Hydrostatic Test Procedure The inspector examined Surveillance Instruction 2-SI-3.3. 1.B, ASME Section XI Hydrostatic Pressure Testing of the Reactor Pressure Vessel and Main Steam Piping (ASME Section III, Class I 5 2).
This procedure specifies" the requirements for hydrostatic testing of the Class I equivalent portions of all systems and the Class 2 equivalent of the main steam system once each 10 year inspection interval, or following any repair or replacement of any component within the test scope.
The inspector verified that test initial-conditions, prerequisites, precautions and limitations were specified; test instructions and objectives were clearly stated; and that acceptance criteria were specified.
The test procedure specifies a
10 minute holding time at test pressure for noninsulated piping and a four hour holding time at test pressure for insulated piping.
During review of the procedure the inspector verified that TS requirements for Primary Containment (TS 3.6.A.2),
and Primary System Boundary (TS 3/4.6.A. 1,
.2,.6, and.7) were specified as test limitations and precautions.
The inspector also reviewed procedure 2-SI-4.6.A.2, Reactor Vessel Shell Temperature and Reactor Coolant Pressure Monitoring.
This procedure requires monitoring of reactor vessel pressure and temperatures at 15 minute intervals to assure pressure/temperatures are as specified in TS Figure 3.6-1 during performance of the hydrostatic test.
T.S.
3.'7.A.2 requires reactor coolant temperature to be maintained be1ow 211'F during the test since primary contain-ment had not been established during performance of the hydrostatic test.
b.
Observation of Hydrostatic Test I
The inspector witnessed the start of the hydrostatic test from the control room.
The inspector monitored pressure and temperature data and verified pressure increases were less than 50 psig/minute and temperature/pressure was maintained within parameters specified in TS Figure 3.6-1.
Prior to start of the test, the inspector walked
c ~
down portions of the main steam system and verified that temporary supports had been installed per the requirements specified in the test procedure and referenced Memorandum B22
0812 014, dated August 12, 1988, Subject:
Temporary Support Requirements for Main Steam Hydro Test in Turbine Building.
The inspector also verified selected valve positions to ascertain test boundary conditions were as specified in test
'procedures, and in accordance with standard industry practices.
The inspector attended briefings conducted by the Test Engineers for plant personnel to explain the hydrostatic test procedure and duties of various groups (mainten'ance, gC, operations)
during the test; attended turnover meetings between day and night shift test engineers and directors; and attended shift turnover meetings for control room operators and shift supervisor.
These meetings were well conducted and the inspector noted that test procedures and precautions were explained in detail to all personnel.
The inspector accompanied licensee maintenance personnel on a
walkdown inspection of piping in the drywell when a pressure of 500 psig was obtained.
This walkdown was conducted to identify and document any system leaks (primarily valve packing and mechanical joints),
and to make necessary repairs to minimize leakage at test pressure.
The inspector accompanied licensee gC inspectors for their walkdown inspection of the drywell at test pressure.
This walkdown was to inspect insulated piping, and was conducted after the four hour holding period at test pressure was reached.
Licensee inspectors identified some leakage from mechanical joints, gaskets, and valve packing, but no through-wall leaks or leaks through welded joints were identified.
The licensee documented the leaks on data sheets.
Review of Test Data The inspector reviewed the calculations for determination of the hydrostatic test pressure and verified that the calculated test pressure met design and ASME Code requirements.
The inspector also reviewed reactor coolant system pressure/temperature data, and verified it complied with TS Figure 3-6. 1.
The inspector performed a review of preliminary test data sheets documenting identification of leaks identified during the hydrostatic test.
Within the area inspected, violations or deviations were not identified.
4.
Thermal Expansion Test - Unit 2 (70370)
The inspector reviewed Technical Instruction 2-TI-90, System Thermal Expansion.
This procedure specifies prerequisites, precautions, instructions, and acceptance criteria for performance of the thermal expansion test.
The purpose of this test is to demonstrate that selected piping systems are unrestricted in regard to thermal expansion.
The following systems will be inspected during the thermal expansion test:
reactor drains and vents, standby liquid control, recirculations, reactor water cleanup,, reactor core isolation cooling,
high pressure core injection, residual heat removal, and core spray.
The test will be conducted by performing visual inspections of the piping during various stages of plant operations.
A walkdown will be performed when the temperature of the piping systems is at ambient conditions to collect baseline data.
Interferences which could impede thermal piping movements will be identified during the ambient walkdown.
The minimum clearances between the piping and any other pipe or structure (pipe support, structional steel support, cable tray support, or temporary structure)
is required to be at least I/8 inch plus the predicted piping movement between ambient and normal operating temperature.
" Additional walkdowns will be performed at intermediate reactor water temperature, normal operating temperature, and return to ambient temperatures.
The movements of specific selected hangers (snubbers) will also be recorded during the thermal expansion test.
The inspector also reviewed procedure number SP-6. 13, Program for the Verification, Piping and setting of Variable Spring Supports.
This procedure requires verification that all spring can supports are properly adjusted prior to returning any system to an operable status.
The procedure specifies that all spring cans be adjusted and set after each system 's filled and vented, when the system is at ambient (cold)
conditions.
A second walkdown will be performed during the thermal expansion test when the plant is at normal operating temperature to determine if the hot setting of the spring cans are at predicted design values.
Spring can supports found outside the load setting range at maximum thermal movement will be evaluated and adjusted as required to meet design operating conditions.
Within the areas inspected, violations or deviations were not identified.
5.
Snubber Surveillance Program - Units l-3 (70370)
The inspector examined procedure and quality records related to the snubber surveillance program and inspected snubbers on selected Unit 2 safety-related piping systems.
Acceptance criteria appear in Technical Specification 3/4.6.H.
a ~
Review of Snubber Surveillance Procedures The inspector examined the following procedure which control snubber surveillance activities:
(1)
2-SI-4.6.H.1, Visual Examination of Hydraulic and Mechanical Snubbers (Unit 2)
(2)
2-SI-4.6.H.2, Functional Test of Hydraulic and Mechanical Snubbers (Unit 2)
(3)
MMI 59D, Functional Testing of Mechanical Shock Arrestors, Units 1, 2, and
Cl
b.
c ~
Inspection of Snubbers The inspector performed a visual inspection of selected hydraulic and mechanical snubbers installed on safety-related piping systems inside the Unit 2 drywell.
This inspection was conducted during the hydrostatic test.
The inspector verified that the snubbers were not damaged, that attachment of the snubbers to the supporting structure and piping was secure, and that for hydraulic snubbers, reservoir fluid levels were within target levels.
Review of guality Records k
The inspector reviewed the results of visual inspections conducted on Unit 2 snubbers in February-March 1990.,
The inspector also reviewed results of functional tests performed on various Unit 2 mechanical and hydraulic snubbers in 1990.
The visual inspection and functional testing was performed to ascertain the snubbers met Technical Specification acceptance criteria prior to startup of Unit 2.
Since all snubbers met the visual inspection acceptance criteria, the next visual inspection is required to be performed in September 1991 through January 1992 to comply with the inspection interval specified in TS paragraph 4.6.H.2.
The inspector also examined the licensee's snubber service life program.
The licensee has determined that the service life for seals in hydraulic snubbers is ten years.
The inspector examined the computerized records documenting the Unit 2 snubber seal service life.
These records were incomplete since the start of service life date for the majority of the Unit 2 hydraulic snubbers are not in the computer data base.
The inspector discussed the incomplete service life information in the computer data base with licensee engineers.
These discussions disclosed that the actual service life records are contained in mechanical maintenance records for rebuilding and functional testing of the hydraulic snubbers.
However, these records are difficult to retrieve.
Licensee engineers told the inspector that a thorough review of the Unit 2 snubber service seal life records has been performed to verify that the seals in all Unit 2 hydraulic snubbers are within their 10 year service life.
The computer data base will be updated after startup of Unit 2.
The inspector will review the snubber seal life in a future inspection for selected Unit 2 hydraulic snubbers installed on piping systems inside the drywell.
One difficulty is performing this review is in the need to manually search numerous maintenance records to locate the records documenting rebuilding (including seal replacement)
of a
particular snubber.
The inspector identified the lack of readily retrievable records documenting snubber service life to the licensee as a weakness in their snubber surveillance program.
Within the areas inspected, violation or deviations were not identifie I
6.
Exit Interview The inspection scope and results were summarized on April 8, 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 '