IR 05000259/1992032
| ML18036A867 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 09/25/1992 |
| From: | Blake J, Chou R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML18036A866 | List: |
| References | |
| 50-259-92-32, 50-260-92-32, 50-296-92-32, IEB-79-14, NUDOCS 9210060149 | |
| Download: ML18036A867 (8) | |
Text
UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTASTREET, N.W., SUITE 2900 ATLANTA,GEORGIA 30323 Report Nos.:
50-259/92-32, 50-260/92-32, and 50-296/92-32 Licensee:
Tennessee Valley Authority 3B 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 Conduc ed August 24-28, 1992 Inspector:
C I
R.
C.
Chou Date Signed Approved by:
J
. Blake, Chief a erials and Pr'ocesses Section En ineering Branch Division of Reactor Safety Date Signed
'UMMARY Scope:
Thi.s routine, unannounced inspection was conducted in the area of review of pipe support calculations for safety-related piping systems for Unit 3 ~
Results:
In the areas'nspected, violation's or deviations were not identified.
One Inspector Followup Item (IFI) was identified concerning spring support design.
The spring load calculations for the Recirculation Water System calculated two cold loads while there should be only one.
The calculations for cold load spring settings, for Torus Piping Systems allowed a large setting, range which could deviate from the setting required by the stress calculations.
The licensee was informed about the concerns and agreed to provide information and resolutions for review during next inspection.
9210060149 920928 PDR ADDCK 05000259
REPORT DETAILS
'.
Persons Contacted Licensee Employees R. Biard, Unit 3 Civil Principal Engineer
- P. Baron, Licensing Manager
- C. Crane, Maintenance Manager
- R. Cutsinger, Lead Civil Engineer P.
Dey, Unit 3 Civil Principal Engineer
- H. Herrell, Operation Manager E. Knuettel, Nuclear Engineer
- J. Maddox, Engineering Manager
- L. Madison, Jr., Unit 3 Lead Civil Engineer
- P. Salas, Compliance Manager
- J. Scalice, Plant Manager
- J. Swindell, Unit 3 Restart Operation Manager
- O. Zerinque, Vice President
- Browns Ferry Operation Other licensee employees contacted during this inspection included engineers, technicians, and administrative personnel.
NRC Resident Inspectors
- C. Patterson, Senior Resident Inspector
- E. Christnot, Resident Inspector
- J. Hunday, Resident Inspector 2.
- Attended exit interview Review of Pipe Support Calculations for Unit 3 At the time of this inspection, the licensee had completed all the.
walkdowns and evaluations for the large bore piping.
Support calculations were issued to support Design Change Notices for field modifications, based on the walkdown information, and the new stress loads.
Two design criteria were used for safety-related piping systems to generate new calculations.
(1) Attachment A, General Design Criteria for the Torus Integrity Long-Term Program of Design of Civil Structures, design Criteria BFN-50-C-7100 was used for the design of torus piping systems, This design criteria was developed around 1979 to review the support calculations for torus piping systems in accordance with the Hark I Containment, Long Term Program, which considers new loads, and effects, due to torus water swell during emergency.
(2) The General Design Criteria No. BFN-50-C-7107, Design of Class I Seismic Pipe and Tubing Supports was used for all IEB 79-14 Program except the torus piping systems.
The General Design Criteria No. BFN-50-C-7107 was developed by Stone and Webster Corporation on January 20, 1989 in conjunction with the Browns Ferry Third Piping System Walkdown Program for IEB 79-14.
The design standards contained in this design criteria have more stringent requirements than the design criteria BFN-SO-C-7100,
To verify the licensee performance on the pipe support calculations,
pipe support calculations in four systems were partially reviewed and evaluated for thoroughness, clarity, consistency, and accuracy.
The review included:
that the applied loads used were taken from the latest stress calculation; computer model, computer input and output; check of displacements, member size, weld 'sizes and symbols, bolt sizes, and
~
standard component capacities and settings.
In general, the design cal'culations were acceptable, except as noted in discrepancies/comments.
Listed below, are the support calculations which were partially reviewed by the inspector.
Support No.
Calculation No.
Rev.
System No.
No.
Discrepancies Comment RVVH-19 CD-03001-910928
001 CD-03001-910930
001 The springs were qualified by using a
large cold setting range which was different from the cold settings required by the stress calculations.
A 55 percent of total load was used to design one snubber in the pair of snubbers.
RVVH-1 CD-03001-910931
001 The springs had similar discrepancies to Support No.
RVVH-19.
3-47B450-312 3-47B450-291 3-47B450-279 3-47B450-476 3-47B465-478 CD-Q3023-910500
023 CD'-03023-910479-0 023 CD-Q3023-910467
023 CD-Q3068-910843
068 CD-03068-910845
068 Each spring was calculated to have two cold loads; there should be only one cold load.
The discrepancies were similar to Support No. 3-47B450-476.
3-47B465-463 CD-03068-910830
068 This support was deleted
Discrepancies Comment Calculation No.
Rev.
No.
Support System'o.
No.
(cont',d)
3-47B452-1376 CD-03074-910990
074 This support was deleted 3-478452-1378 CD-03074-910992
074 This support was del'eted Support Nos.
RVVH-19, RSSC 1&2, and RVVH-1 are in Piping System 001 around the torus, and.were included in the Torus Integrity Long Term Program.
The new loads generated for this piping system were based on
'he Hark I Containment Program
- Structural Acceptance Criteria, Plant Unique Analysis Application Guide performed by General Electric Company which accounted for loss-of-coolant accident (LOCA) and safety/relief valve (S/RV) hydrodynamic loads.
The design criteria BFN-50-C-7100 was used for the torus piping systems.
This design criteria is different from design criteria BFN-50-C-7107 which was used for the IEB 79-14 reconciliation program.
Example 1,
BFN-50-C-7100 uses 55 percent of total loads to design a snubber in a pair of snubbers.
BFN-50-C-7107 used 60 percent instead of 55 percent.
Support No.
RSSC 182 used
percent of totalload to design snubber.
Example 2, Section 4.5.2.3 of BFN-50-C-7100 allows the spring cold load setting to be in a range which is the allowable working range of the spring minus the maximum travel requirements for the up or down movements.
BFN-50-C-7107 allows the spring to be set in one particular load location only.
Support Nos.
,RVVH-19 and 1 allowed a large range to be used for the cold load settings.
If the cold load settings can be a range, then the actual cold load settings may not be the specific setting required by the stress calculations.
There were no variability checks for the spring design in the torus piping systems by using BFN-SO-C-7100.
Support Nos.
3-47B465-476 and-478 calculations had two cold loads for each spring design.
There should be only one spring cold load for the cold load setting.
The licensee's engineers calculated two cold loads based on a hot load and maximum and minimum movements from the hot condition.
The engineer chose one of two for the cold load setting.
The choice could be right or wrong.
Genei al Electric Company (GE)
performed the stress analysis for system 068 and sent the stress calculation package to the licensee; the package included the analyses for several, different load cases.
The correct load case to use to calculate the cold load was the load case for the normal operating condition.
This case was not sent to the pipe support design engineers to calculate the actual cold load by the pipe stress analysis group who received the packages.
Instead, the design engineer used the minimum, and maximum movements to calculate two cold loads which, in most cases,
'ere not the actual cold load.
Based on the discrepancies found above, the inspector summarized the concerns shown below.
This is identified as Inspector Followup Item 50-259, 260, 296/92-32-01, Design Problems in Spring Supports.
The concerns are:
J
~
t
'
a.
Two different design criteria BFN-50-C-7100 and BFN-50-C-7107 exist for the piping system design, b.
Why was the torus piping systems not included in the IEB 79-14 program (using BFN-50-C-7107)?
c.
A large range for spring cold load setting was used in torus piping system design.
d.
Two cold loads were calculated in system 068 instead of one cold loads Exit Interview The inspection scope and results were summarized on August 28, 1992, with those persons indicated in paragraph 1.
The inspector described the area inspected and discussed in detail the inspection results listed below.
Proprietary information is not contained in this report.
Dissenting comments were not received from the licensee.
(Open)
Inspector Followup Item 50-259, 260, 296/92-32-01, Design Problems in Spring Supports