IR 05000259/1989034
| ML18033A928 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/16/1989 |
| From: | Blake J, Coley J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18033A927 | List: |
| References | |
| 50-259-89-34, 50-260-89-34, 50-296-89-34, GL-88-01, GL-88-1, IEB-83-02, IEB-83-2, IEIN-88-082, IEIN-88-82, IEIN-89-001, IEIN-89-1, NUDOCS 8909070196 | |
| Download: ML18033A928 (12) | |
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UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTASTREET, NAV.
ATLANTA,GEORGIA 30323 Report Nos.:
50-259/89-34, 50-260/89-34, and 50-296/89-34 Licensee:
Tennessee Valley Authority 6N 38A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Docket Nos.:
50-259, 50-260 and 50-296 License Nos.:
DPR-33, DPR-52, and DPR-68 Facility Name:
Browns Ferry 1, 2, and
Inspection Conducted:
July 25-28, 1989 Inspector:
J. L; ey
. (,.I Approved by:
J.
J~'
ake, Chief Materi ls and Processes Section En)ineering Branch Division of Reactor Safety Date Signed C~
g c
Date igned SUMMARY Scope:
This routine, unannounced inspection was in the areas o
ol'.owup of Generic Letter 88-01 work activities, review of'icensee corrective actions on previous inspection findings, review of corrective actions regarding licensee event report (LER)
259-83-049, and review of licensee actions regarding NRC Information Notices 89-01 and 88-82.
Results:
Licensee responsiveness to NRC initiatives was very good.
Corrective actions taken on previous inspector findings was thorough.
An apparent soft ware problem was identified by the inspector on TVA's automated ultrasonic system (Introspect I-98) that may have hardware implications.
The licensee is investigating this finding.
In the areas inspected, violations or deviations were not identifie o
REPORT DETAILS 1.
Persons Contacted Licensee Employees
- R. Boyd, Regulatory Licensing P. Carier, Manager, Regulatory Licensing
- E. Hartwig, Project Management J.
McCarthy, Supervisor Regulatory Licensing
- R. Seals, Engineer, Nondestructive Examination J. Swindell, Assistant Plant Manager Other licensee employees contacted.during this inspection included engineers, technicians, and administrative personnel.
Other Organizations S.
N. Mager, Combustion Engineering NRC Resident Inspectors
- D. Carpenter, NRC Site Manager
- W. Bearden, Resident Inspector
- E. Christnot, Resident Inspector
- K. Ivey, Resident Inspector
- Attended exit interview 2.
Observation of Generic Letter 88-01 Work Activities Unit 2 (92701)
Generic Letter 88-01 (GL 88-01)
"NRC Position on Intergranular Stress Corrosion Cracking ( IGSCC) in BWR Austenitic Stainless Steel Piping" was issued on January 25, 1988 to distribute and release NUREG-0313, Revision
"Technical Report on Material Selection and Processing Guidelines for BWR Coolant Pressure Boundary Piping."
TVA submitted their response to GL-88-01 on August 1, 1988.
On December 8, 1989 NRC issued TVA a Unit-2 Safety Evaluation Report (SER),
based on the August 1, 1988 response, which required that TVA address the following concerns before Unit 2 restart:
a..
TVA provide confi rmation that the weld sample expansion requirements comply with the "Staff Position" on sample expansion established in GL 88-0 b.
TVA address post-induction heat stress improvement (IHSI)
inspection of the remaining uninspected Unit 2 welds prior to Unit-2 restart.
c.
TVA provide Technical Specification (TS)
changes to reflect leak detection requirements specified in GL 88-01.
On January 12, 1989 TVA submitted a
response to NRC which addressed items a
and c above.
The TS for leak detection requirements of GL 88-01 were approved and issued by NRC on May 19, 1989.
The post-IHSI inspections required in item b were completed in triarch 1989.
The results of the post-IHSI inspection of the
welds revealed
Structural analysis was performed on all 8 welds per the guidance provided in GL 88-01 and NUREG 0313, Revision 2.
This analysis indicated that indications in welds GR-2-53, DRHR-2-22 and DRHR-2-9 were acceptable for continued operation until the next scheduled examination period required per GL 88-01.
The three welds also had received IHSI and therefore crack growth was estimated to be minimal.
The five remaining welds were determined to require repair.
Welds GR-2-59 and GR-2-61 were repaired by the application of "full structural" weld overlays as provided under Design Change Notice (DC) H-4972.
Welds GR-2-45, DSRWC-2-4, and DSRWC-2-3 were repaired by the application of
"design" weld overlays as provided under DCN-H-5077.
The design of all
weld overlays was accomplished using the guidance provided in NUREG 0313, Revision 2.
On July 11, 1989, TVA notified Region II that the 5 we'ld overlays would be ultrasonically examined in accordance with GL 88-01 during the week of July 24-28, 1989.
On July 25, 1989 the inspector arrived at the Browns Ferry site to observe the ultrasonic examinations, review the examination procedures and to verify equipment and personnel certifications used to perform the weld overlay examinations.
Details of the inspector's review are delineated below:
(1)
Review of Procedures The inspector reviewed the following procedures to ascertain whether the licensee's procedures, pertaining to the examination of weld overlayed piping, specified licensee commitments, qualification/certification requirements of examiners, proper equipment to perform the examinations, methods of calibration, methods/techniques of examinations, extent of coverage, method of recording, and methods of evaluating and disposi tioning findings.
Procedure Titie N-UT-57 Rev.
Automatic Ultrasonic Examination of Weld Overlayed Piping Joints
Procedure cont N-UT-28 Rev.
Title Ultrasonic Examination of Weld Overlayed Piping Joints (Manual, Examination (2)
gualification/Certification of Examiners.
Combustion Engineering (CE) ultrasonic examiners working to TYA's quality assurance program and procedures were used by TVA to conduct the weld overlay examinations.
qualifications and certification records revealed that both examiners had been qualified at the Electric Power Research Institute (EPRI) in Charotte N.
C.
on weld overlays.
Records of the following examiners were reviewed:
Examiner Level of Certification Methods of uglification
- G.A.T
- E.J.T L-111 L-11 Acquisition and Analysis Acquisition (3)
- Note:,
Both examiners were qualified for the manual method of IGSCC examination Equipment Certification and Calibration Records Review.
Certification and calibration records for the following equipment were reviewed by the inspector.
E ui ment Identification
- Introspect-98 Receiver 008
- Introspect-98 Remote Pulser Preamplifier Introspect-98 Receiver 007 Introspect-98 Remote Pulser Preamplifier
- RTD 60'TRL 2 Aust SA24'FS-20 Krautkramer/Branson MSEB-4 Krautkramer/Brason MSEB-4 Sigma 2MHZ 2(10X12MM)
RTD 70'TRL-2-Aust SA 16'FS-20 RTD TRCR2-Aust SA 10'FS-20 RTD TRCR4-Aust SA28 FS-10
'TD 70'TRL-2 - Aust SA 5'S-25 RTD TRCR-2-Aust SA-10'S-20 Reference Calibration Block 1"Angle Beam Reference Calibration Block 1"Angle Beam Serial No.
RDAS S/N 07-85-002 RPP/SN/09-85-003 RDAS SN/09-85-005 RPP S/N 011-86-017 S/N 85-632 S/N 01561 S/N G29553 S/N 2403-88001 RO S/N 85-635 S/N 83-G36 S/N 83-G32 S/N 85-739 S/N 85-737 S/N 85-740 S/N 83-937 S/N 6030-83 S/N 789630 Note:
Equipment used by licensee during inspector's observation of'ork activitie (4)
Observation of Work Activities (Acquisition of Data)
The inspector observed CE's Level II ultrasonic examiner perform circumferential
'scans on weld GR-2-59 and circumferential and axial scans on weld GR-2-61.
To insure that the examiner was knowledgeable of the examination method and operation of the test equipment the inspector questioned certain system parameters such as gate settings, sensitivity, and depth of sound penetration.
As a result of this questioning it was determined by the inspector and TYA's Level III Examiner that the depth of the calibration reflectors depicted on the computer's hardcopy graphics for the initial calibration of weld GR-2-59 were in error.
In addition, the thickness reading displayed on the computer screen was also incorrect.
The error was significant and apparently the result of a sotfware problem when the system was operated in the circular scan mode.
AMDATA the manufacturer of the Introspect-98 System was notified of the error.
TVA initially thought the error was in the last revision of the computer program (VIP 4. 1 Revision D) since the problem had not been identified before.
However, preliminary investigation of the problem by AMDATA, has tentatively determined that the error was made in Revision A of the computer software program.
A review of AMDATA's technical manual (TM) by TVA's Level III Examiner also revealed that the TM was inadequate for setting up the circular scan feature because the instructions did not explain whether metal path or depth was to be used in the trigonometric calculations.
TYA performed subsequent calibrations using both metal path and depth only to find that neither worked in the program.
The error in the program apparently is not a significant safety concern because the error is in a conservative direction.
However, indications in piping systems will appear I/3 deeper than their actual depth possibly causing inaccurate design information and unnecessary weld repairs.
Welds most susceptible to software error will be those which required sizi ng of planar defects and weld overlays.
A preliminary review of 66 welds examined in March 1989 after IHSI did not identify any welds which had been examined using the circular scan feature.
TYA agreed to look at all welds examined with the Introspect-98 for depth mis-calcuations.
In addition, TVA will take the necessary corrective actions with AMDATA to insure the error in the software and the inadequacies in the TM will be corrected and that training on this feature will be uniform.
This item was reported to the licensee as Unresolved Item 50-259, 260, 296/89-34-01
"Introspect-98 Software,has Apparent Circular Scan Depth Calculation Error".
k Within the areas examined, violations and deviations were not identifie.
NRC Information Notices (IN)
a ~
b.
IN-89-01, "Valve Body Erosion" During the Brunswick Steam Electric Plant, Unit I refueling outage, inspections performed on December 13, 1988, indicated areas of significant but localized erosion on the internal surfaces of several carbon steel valve bodies.
A similar problem appeared to have occurred at Hatch Unit I on November 17, 1988.
The apparent cause of the valve erosion was due to throttling globe valves below their design flow range, therefore, NRC issued 'nformation Notice 89-01 to alert other licensee of this potential problem.
The obvious safety concern being that continued operation without weld repair or replacement could lead to rupture of safety-related valve bodies.
During this inspection the inspector reviewed TVA actions in response to this potential safety issue and discovered that the licensee had identified seven similar valves susceptible to valve body erosion.
The licensee will examine six of the valves ultrasonically to determine if any erosion has occurred and one valve FCV-71-10 will be inspected during its upcoming 10 year inspection or whenever maintenance is required.
The licensee's actions with regards to this concern appears satisfactory.
"Torus Shells with Corrosion and Degraded Coatings in BWR Containments" During NRC inservice inspections (Report No. 50-220/88-09 and 50-410/88-09)
at the Nine Nile Point Nuclear Stations, inspections found that the inside surface of the torus shell at Unit I, which was designed and constructed as uncoated, had corroded.
Furthermore, the NRC inspector's independent thi ckness measurements of the torus shell revealed several areas in which the thickness was at or below the minimum specified wall thickness.
The apparent safety significance of the torus shell degradation, if continued would be jeopardizing the containment integrity.
On July 27, 1989, the inspector reviewed TVA's actions with regards to this potential safety issue."
The following is a
summary of licensee's actions for each unit at Browns Ferry:
The torus for BFN Units I, 2 and 3 were painted at the time of their installation.
Technical Specifications Surveillance Instruction (SI)
4.7.A.2.K required inspection of the torus one-foot below the normal water line each refueling outage.
Any significant deterioration discovered at this location, required the entire interior of the torus would be inspected and repaired.
After -installation of the.torus, inspections were performed as required and coating repairs performed in 1975 and 1976.
Subsequent to the coating repairs, inspections were satisfactory.
In 1983
Engineering Changed Notice (ECN)
P0555 was issued. to completely inspect and recoat the torus as necessary.
The work completed on this ECN was performed on the following workplans (WPS):
Unit 1 -
WP No.
10257 (coating repair completed in October 1983)
Unit 2 -
WP. Nos.
2008-84, and 2127-84 (entire torus internal sandblased and recoated; completed in 1984)
Unit 3 -
HP No.
13085 (coating repair completed in April 1984)
The most recent inspections and results for Units
and 2 and the schedule for inspecting Unit 3 is given below.
Unit 1 - Inspected and coating repair completed September ll, 1988 Unit 2 - Inspected September 7,
1988 with no repairs needed Unit 3 - Inspection will be in accordance with the technical specification SI and is currently scheduled for mid-1989.
TVA considers the condition described in,the IN Notice not applicable to Browns Ferry for the following reasons:
1.
There is sufficient administrative control for detection (SI 4.7.2.A.K) of corrosion damage.
2.
The torus shells have been coated since oper ation began.
3.
The shells have been upgraded to a heat cured epoxy coating system.
The licensee actions regarding this potential safety issue appear to b'e satisfactory.
Within the areas examined, violations or deviations were not identified.
4.
On site Followup of Events at Operating Power Reactors (92700)
(Closed)
Licensee Event Report 50-259/83-049:
On August 26, 1983 TVA reported to Region II, that ultrasonic examinations on Unit 1 had detected intergranular stress corrosion cracking ( IGSCC)
in their austenitic stainless steel piping as a result of augmented inspections performed in accordance with NRC Bulletin 83-02 and NUREG 0313.
All welds with IGSCC indications over a
predetermined size were subsequently repaired
.utilizating the weld overlay repair method.
Region II conducted inspections of the examination and repair activities and NRR also issued a Safety Evaluation Report on these actions prior to Unit 1 returning to service.
This item is considered closed.
Wi:hin the area examined violation or deviations were not identifie.
Licensee Action on Previous Inspection Findings (92701 and 92702)
a.
(Closed) Violation 50-260/88-06-01,
"Failure to Follow Procedure for Prevention of Foreign Material in Reactor Vessel Cavity" TVA Letter of Response dated May 23, 1988 was reviewed and accepted by Region II.
The inspector witnessed TVA's corrective actions during a
subsequent inspection ( Inspection Report 50-259,260, 296/88-15)
when ultrasonic re-examinations were performed on the shroud manway cover in accordance with plant procedures.
In addition, the inspector reviewed TVA's extensive corrective action package for the finding and considers TVA has taken the necessary precautions to prevent this problem from recurring.
b.
(Closed)
Unresolved Item 50-259, 260, 296/89-05-01,
"Amended Response to the Office of Nuclear Regulations Required for Generic Letter 88-01" In response to Generic'etter 88-01, TVA had not addressed the 6-inch, 5-inch or 4-inch diameter reactor water cleanup (RWCU) system piping outside the drywell penetration.
This piping contains reactor coolant and operates at temperatures exceeding 200'F, and is nonconforming stainless steel.
At the time of the inspection, the term "regardless of code classification" was interpreted by TVA as meaning only piping that had an ASME Code classification.
The RWCU piping outside the drywell at Browns Ferry was not ASME Code piping.
Following the inspection, a
TVA/NRC Teleconference was held to discuss the RWCU piping issue.
The term non-code class was defined by NRC to include all piping both ASME Code class and non-ASME Code class.
As a result of this interpretation TVA presented a
supplemental plan to NRC on April 20, 1989, in a meeting held at Rockville, Maryland.
TVA also issued a supplemental response to Generic Letter 88-01 on June 30, 1989, which stated that all non-conforming stainless steel piping on the RWCU system would be replace with conforming material.
Replacement for Unit 2 would occur during the Unit 2 Cycle 6 outage and replacement for Units I and 3 would occur prior to their restart.
TVA also corrected in the June 30, 1989, supplemented response the scope of post IHSI examinations from 71 welds to 66 welds.
The licensee actions with regard to this issue are satisfactory and this item is considered closed.
Within the areas examined, violations or deviations were not identified.
6.
Exit Interview The inspection scope and results were summarized on July 28, 1989, with those persons indicated in paragraph 1.
The inspector described the areas inspected and discussed in detai
the inspection results listed below.
Proprietary information is not contained in this report.
Dissenting comments were not received from the license (Open)
Unresol ved Item 50-259, 260,296/89-34-01,
"Introspect-98 Software has an, Apparent Circu1ar Scan Depth Calculation Error,"
paragraph 2(4).