IR 05000259/1991034
| ML18036A430 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/11/1991 |
| From: | Blake J, Chou R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18036A429 | List: |
| References | |
| 50-259-91-34, 50-260-91-34, 50-296-91-34, IEB-79-14, NUDOCS 9111200013 | |
| Download: ML18036A430 (15) | |
Text
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+iI.*~4 UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION II
10'I MARIETTASTREET, N.IN.
ATLANTA,GEORGIA 30323 Report Nos.:
50-259/91-34, 50-260/91-34, and,50-296/91-34 Licensee:
Tennessee Valley Authority 6N 38A Lookout PIace 1101 Ha rket Stree t Chattanooga, TN 37402-2801 Docket Nos.:
50-259, 50-260 and 50-296 License Nos.:
DPR-33, DPR-52, and DPR-68 FaciIity Name:
Browns Ferry 1, 2.
and
inspection o
c September 9-13, 1991 Inspecto i/ 0/
Date Signed Approv d b
J J
Blake, Chief ia rials and Processes Section E gineering Branch Division of Reactor Safety Date Signed SUMMARY Scope:
This routine.
unannounced inspectior was conducted in the area og walkdown reinspection of the safety-related piping systems for I Bulletin 79-14 on Unit 3 restart.
Results:
In the areas inspected, violations or deviations were not identified.
911120001I
~j11021 PDR ADOC)( 0b000259 Q
REPORT DETAILS Persons Contacted Licensee Employees
- T. Abney, Unit 3 Technical Support Manager
- R. Baird, Unit 3 Lead Civil Engineer
- P. Baron, Quality Control (QC) Manager
- P. Carier, Site Licensing Manager
- L. Clardy, Monitoring Supervisor
- J. Corey, Radcon Manager
- K. Groom, Modification Engineer
- E. Hartwig, Unit 3 Project Manager
- N. Herrell, Plant Operation Manager
- T. Knuettel, Unit 3 Licensing Engineer
- D. Massey, Regulatory Licensing Engineer
- J. NcCarthy, Unit 3 Licensing Manager
- J. Rupert, Engineering Manager
.
- J. Swindell, Unit 3 Restart Operation Manager
- J. Yalente, Civil Engineer Supervisor Other licensee employees contacted during this inspection included craftsmen, engineers, mechanics, technicians, and administrative personnel.
Bechtel Power Corporation
- D. McGlynn, Integrated Walkdown Pipe Support Group Lead R. Montgomery, Integrated Walkdown Manager
- A. Sidhu, Project Engineer for Browns Ferry Unit 3 NRC Resident Inspectors
- C. Patterson, Senior Resident Inspector
- W. Bearden, Resident Inspector
- E. Christnot, Resident Inspector
- K. Ivey, Resident Inspector
- Attended exit interview Licensee Action on Pipe Support Modification for Unit 3 Reference I:
"Pipe Support Base Plate Design Using Concrete Expansion Anchor Bolts"
Reference 2:
"Seismic Analyses for As-Built Safety-Related Piping System" a ~
Status Tennessee Valley Authority {TVA) has successfully completed the modification of,Unit 2 and has decided to follow the Unit 2 special program and.procedures for piping and supports (large bore) for Unit 3 restart.
The current proposal to complete the Unit 3 piping system modifications, to meet the licensee commitments and regulatory requirements, is that Bechtel will perform the design and engineering work, which includes the piping system walkdown reinspection, and Stone and Webster will perform the field modifications.
Bechtel will use three separate programs to complete the piping system evaluations and modifications to meet IE Bulletin 79-14.
The three programs include the large bore program, the torus piping program, and the small bore and tubing program.
Bechtel started the large bore walkdown reinspection in late April 1991.
Bechtel will use three stages to perform the piping system walkdown reinspection and check the quality of the walkdown reinspection.
The
. three stages are described as follows:
{I) Field Walkdown - perform the field walkdown reinspections to check or collect the discrepancies between the existing drawings and the field condition.
(2)
Sanity check - review the walkdown packages and request more information if required.
(3)
95/95 Audit -
Randomly select walkdown sheets and perform a
complete recheck on the walkdown sheets until the walkdown packages in the system meet the 95 percent confidence level.
The walkdown sheets include the drawings, sketches, or inspection and information sheets.
The walkdown packages will be released to the document control room after the packages reached a
percent confidence level.
The large bore program includes a schedule to complete 2400 pipe supports and 29500 ft piping.
Bechtel has completed the piping and supports in the three stages as shown below.
All walkdown reinspection for the large bore piping and supports will be completed by mid-October 1991.
Item Fiel d Walkdown Sanity 95/95 Document Check Audit Control Release Piping 20500ft Support 1200 I3000ft 7000ft 7000ft 900 600 600
The torus piping systems
.have seven systems and approximately 600 supports and have a
schedule for the walkdown reinspection to be completed by end of October 1991.
The small bore and tubing walkdown reinspection was started in August 1991 and will be completed by August 1992.
The licensee will start the stress reanalyses for the large bore around December 1991 and will perform the field modifications starting in February 1991.
- The main purpose of this inspection
'was to verify the performance and adequacy of the licensee walkdown reinspection for the large bore piping systems on Unit 3.
The verification included piping and supports.
b.
Procedures The following procedures were developed by Bechtel and TVA to be used for the walkdown reinspection and engineering evaluation.
More procedures will be developed for the design calculations and the field modifications.
The inspector reviewed the large bore walkdown procedure BC-005.
The rest of procedures were listed for reference.
Procedure Revision Title BC-005 BC-012 BC-016 Walkdown Instruction For Piping and Pipe Support (Large Bore)
Engineering Attribute Walkdown Instructions for Seismic Class I Small Bore Piping, Tubing, and Associated Supports General Requirements For Integrated Walkdowns c ~
8 FN-50- C-7107 BFN-50-C-7103 Walkdown Reinspection Design of Class I Seismic Pipe and Tubing Supports Structural Analysis and gualification of Mechanical and Electrical Systems (Piping and Instrument Tubing)
The inspector randomly select 160ft of piping and 22 pipe supports which had previously been accepted by licensee (}C inspectors.
The 160ft of piping and 22 pipe supports were all in large bore piping for four different safety-related systems located both inside and outside of the drywell.
The drawings used by the NRC inspector for the walkdown reinspection were the drawings generated and compiled by Bechtel after
their walkdown reinspection.
The walkdown reinspection was completed with assistance from Bechtel's walkdown inspectors who were a lead piping inspector and a lead support inspector who had received special training on welding inspection.-
The piping was checked for configuration identification, dimension, pipe size, pipe material, fitting, valve operator orientation, branch, support location, support load direction, support type, and interference.
The supports were checked for configuration,'dentification, fastener/anchor installation, anchor size, anchor type, anchor marking, anchor edge distance, base plate size and thickness, plate warpage, member size, weld sizes, component identification numbers, components sizes and settings, dimensions, oxidation accumulation, maintenance, and damage protection.
The piping and supports reinspected during the current inspection are listed below.
TABLE 1'alkdown Reins ection Pi in Item No.
Isometric No.
Inspected Len<eth Comment/Oiscrepancies/
Licensee Remedies N1-374-25R-01 N1-373-10R-01 40ft ( 1)
The operator orientation on valve No.
FCV-73-02 was not shown as required by walkdown procedure.
(The licensee will generate Condition Affected Quality Report (CAQR) to recheck all 'walkdown packages for the missing operator orientation and require all walkdown inspectors to record the operator orientation.)
(2)
The 1"d branch=
had only 3/4" clearance with the adjacent 3"d pipe.
The walkdown isometric did not record the interference with the 3"d pipe.
The licensee will revise the walkdown procedure to require that all interferences with the piping to be inspected within 2"
should be recorded.
N1-323-3R-01 N1-373-05R-01 87ft 33ft
TABLE 2 Walkdown Reins ection Su orts Tag No.
03414 03413 02424 TVA Mark No.
H-152 Isometric No.
Nl-374-25R-Ol Nl-374-25R-01 N1-373-10R-01 Comment/Discrepancies/
Licensee Remedies The vertical bracing of this support was in contact with a 3"d pipe of Isometric Nl-370-2R-Ol. The inter-ference was not recorded in the support walkdown sketch, but was recorded on the walkdown sketch of isometric N1-370-2R-01.
The licensee agreed to revise the walkdown procedure and record any inter-ference with support within 2" distance for a cross reference.
Tag TVA Isometric No.
Mark No.
No.
02427 R-6 N1-373-10R-01 02428 H-48 Hl-373-10R-01 Comment/Discrepancies/
Licensee Remedies 04808 04809 N1-373-10R-01 N1-373-10R-01 00778 R-51A Nl-323-3R-01 00610 R-52 N1-323-3R-01 00766 R-60 N1-323-3R-01 00770 R-53 N1-323-3R-01 Three fillet welds at the connection between the angle bracing and the base plate were undersized
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16 00768 R-71 N1-323-3R-01 00769 PA-122-1 N1-323-3R-01 02230 R-41 Nl-373-05R-01 02228 R-42 N1-373-05R-01 02226 R-43 N1-373-05R-01 with a maximum undersize of 1/8".
TVA will revise the walkdown sketch and retrain the walkdown personnel.
One fillet weld at the connection between the wide flange and the base plate was undersized by 1/16"..
Item No.
19
21
02224 R-44 Tag TYA No.
Nark No.
02231 R-83 02229 02225 R-94 02227 02853 N1-373-05R-01 Isometric No.-
Nl-373-05R-01 N1-373-05R-01 N1-373-05R-01 N1-273-05R-01 N1-373-05R-01 Cooment/Oiscrepancies/
Licensee Remedies Two nuts were not shown on the walkdown drawings and the term
"bolt" was misused, should be "stud" instead.
The licensee will revise the walkdown drawings to reflect the actual conditions.
An oversized hole was found in a pipe clamp.
The licensee will revise the walkdown drawings to reflect the actual field condition.
The licensee will revise the walkdown procedures to include the interference check within 2" from the support or piping which is being inspected for discrepancies.
This means that all interferences
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within 2" of piping and support to be inspected will be recorded.
The licensee also will retrain their walkdown personnel to do weld size measurement precisely since four fillet welds were found undersize up to I/8".
During the walkdown reinspection, the inspector asked about the acceptance criteria for the gap between a base plate and the concrete surface.
The licensee's engineers presented the General Engineering Specification G-32, Rev.
15, '-'Bolt Anchors Set In Hardened Concrete."
Per Paragraph 4;6. 1.2 of this specification, the gap can be as large as 3/16" all around the edge of the base plate, even in the center of the base plate, since it does not have any limitation on the minimum contact area between the base plate and the concrete surface.
The inspector pointed out to the licensee's engineers that a-situation in which the base plate which can be lifted up without contacting the concrete is an inadequate condition and is unacceptable due to the rigidity reduction in the support.
The support in this condition could become 'flexible in contrast to the rigid condition assumed in the piping stress calculation.
If the licensee insists that there is no problem to have a full gap under the base plate, the licensee should be able to provide, a
computer analysis for the support rigidity to meet the rigidity requirement assumed in the stress calculation.
This area will be reviewed during the future inspection.
No violations and deviations were identified in this area.
3.
Exit Interview The inspection scope and results were summarized on September 13, 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 licensee.
The licensee's engineers telephoned Region II on September 16, 1991, to discuss the discrepancies found during the inspection and the resolution stated in Paragraph 2.c.
The gap problem between the base plate and the concrete surface was discussed in telephone conferences between the licensee and NRC inspector on September 18 and 24 due to the unavailability of the licensee's engineers during the site inspectio ~
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