ML18033A158
| ML18033A158 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 03/10/1988 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| Shared Package | |
| ML18033A159 | List: |
| References | |
| TAC-00298, TAC-298, TAC-R00298, TAC-R00299, TAC-R00300, TAC-R298, TAC-R299, TAC-R300, NUDOCS 8803170014 | |
| Download: ML18033A158 (9) | |
Text
t ACCELERATED DIST IBUTION DEMONSTRn.
ON SYSTEM ACCESSION NBR:8803170014 DOC.DATE: 88/03/10 NOTARIZED: NO FACIL:50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee AUTH.NAME AUTHOR AFFILIATION GRIDLEY,R.
Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)
SUBJECT:
Provides info on seismic qualification of HVAC Ductwork Supports
& forwards Civil Engineering Branch Instruction.
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TENNESSEE VALLEYAUTHORITY CHATTANOOGA. TENNESSEE 37401 5N 157B Lookout Place MAR i 0 1999 U.S. Nuclear Regulatory Commission ATTN:
Document Control Desk Nashington, D.C.
20555 Gentlemen:
In the Matter of Tennessee Valley Authority Docket Nos.
50-260 BRONNS FERRY NUCLEAR PLANT (BFN) SEISMIC QUALIFICATION OF HVAC DUCTHORK AND SUPPORTS This letter describes the BFN program for the seismic qualification of HVAC ductwork.
This material was requested by R: J. Clark's letter dated July 31, 1986, to S..A. Nhite.
This letter supplements the information provided by R. Gridley's letter dated April 8,
- 1987, and section III.3.5 of revision 1 to the Browns Ferry Nuclear Performance Plan that was transmitted by S. A. Nhite's letter dated July 1, 1987.
Enclosure 1 to this letter describes the BFN program for resolving this issue.
Enclosure 2 is the BFN Class I HVAC duct and'uct support seismic qualification interim operability acceptance criteria.
TVA requests your review of. this program and the, issuance of a written statement documenting the programs acceptability.
Please refer any questions regarding this submittal to M. J.
May, Manager, BFN Site Licensing, (205) 729-3570.
Very truly yours, TENNESSEE VALLEY AUTHORITY R. Gri ey, ire tor ~
Nuclear Licensing and Regulatory Affairs Enclosures cc:
See page 2
88031700i4 8803io PDR ADOCK 05000260 P
DCD An Equal Opportunity Employer
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U.S. Nuclear Regulatory Commission MAR i.0 1888 cc (Enclosures):
Mr. K. P. Barr, Acting Assistant Director for Inspection Programs TVA Projects Division U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NH, Suite 2900 Atlanta, Georgia 30323 Mr. G.
G. 2ech, Assistant Director for Projects TVA Projects Division U.S. Nuclear Regulatory Commission One Nhite Flint, North 11555 Rockville Pike Rockville, Maryland 20852 Browns Ferry Resident Inspector
.Browns.-Ferry Nuclear Plant Route 12, P.O.
Box 637
- Athens, Alabama 35611
Enclosure 1
TENNESSEE VALLEY AUTHORITY BRONNS FERRY NUCLEAR PLANT (BFN)
UNIT 2 QUALIFICATION OF SEISMIC CLASS I HVAC DUCTHORK AND SUPPORTS This report gives TVA's plan to qualify the as-configured seismic Class I HVAC ductwork installation.
Issue Design deficiencies were identified in TVA's Significant Condition Report No.
SCRBFNCEB8603 that was issued during February 1986.
Subsequent walkdowns of the HVAC ductwork were performed by TVA, and discrepancies were noted between as-constructed installations and the original design.
~Back round Initially, HVAC ducts and duct supports at BFN were fabricated to industry standards without consideration of seismic loads.
In 1970, the need for HVAC ducts to be designed for earthquake loads was identified.
As a result, modification of existing HVAC ducts and supports was initiated.
An HVAC seismic design criteria was issued in July 1970 and transmitted to the BFN Project Manager for implementation.
The duct construction was based on the Sheet Metal and Air-Conditioning'ational Association (SMACNA) standards, with both the pocket-lock and companion-flange types being used.
Several field evaluations (at least one per unit) were made by design engineers to review the as-built ins'tallations against the design criteria.
Recommendations were made as a result of the field evaluations and changes were made accordingly.
In January
- 1986, a significant condition report was written against the design criteria (BFN-50-721) used for installation and qualification of supports for the HVAC system.
That report questioned whether the design criteria was adequate to ensure the necessary seismic qualification of the HVAC system.
In addition, field investigations of the HVAC system led to concerns that significant discrepancies might exist between the as-built system and the requirement of the design criteria.
Resolution The scope of this activity involves 9500 ft of ductwork, ranging in size from 6 in. to 30 in. diameter round ducts, and 5 in.
x 6 in. to 72 in.
x 84 in.
rectangular ducts.
There are 600 deadweights, 300 two-way and 100 three-way supports for the duct systems.
As-built sketches are generated as part of the walkdown effort and will document key attributes of the systems including the locations of supports and attachments, as well as their construction details and anchorage.
The key attributes for the ducts which will be documented are routing, size, construction,
- location, and types of attachments.
The technical design criteria has been revised to include the correct weight of the ducts, and the duct systems'atural frequency calculation methods have been modified to reflect test results.
Additionally, the revised criteria now addresses cantilevered ducts and DBE (SSE) loads; and the allowable stresses are based on the AISC and the SMACNA standards.
The FSAR requires that essential HVAC systems remain functional for all plant conditions.
The design criteria used in the qualification are based on AISC and SHACNA allowables which ensure that their HVAC systems remain functional.
The approach used for qualification of the duct systems is to evaluate 100 percent of the ductwork and supports against the design criteria stress levels for DBE (SSE) loads.
Those ducts or supports that do not meet the design criteria will be evaluated against the interim operability criteria.
Those which did not meet the design criteria, but are within the interim operability criteria, will be modified to the design criteria after restart.
Those which do not meet the interim operability criteria will be modified to the design criteria unless specifically requested and approved by NRC on a case-by-case basis before restart.
A comparison of design and operability criteria is summarized in table l.
Licensin Issue This program utilizes interim operability acceptance criteria for ducts and duct supports.
Justification The duct stress interim operability. criteria are based on test data (see table
- 1).
The duct support interim operability criteria are the same as the pipe support interim operability criteria, which are similar to the Sequoyah Nuclear Plant' large bore pipe support operability criteria.
Approval of the Sequoyah operability criteria is documented in NUREG 1252.
The HVAC qualification is comprehensive and provides assurance that the ducts and supports will remain functional.
Those modifications which are required to meet the design criteria will be completed before restart following the next refueling outage.
TABLE 1
BROHNS FERRY UNIT 2 HVAC CRITERIA COMPARISON CHART ADDRESSES DESIGN CRITERIA OPERABILITY CRITERIA REMARKS ALLOHABLE DUCT 8,000 PSI STRESS RECTANGULAR PER SMACNA DUCTS 12,000 PSI BASED ON TEST DATA REPORTS TVA-CEB-79-7 AND MA 2-79-1 ROUND DUCTS 10,000 PSI PER SMACNA 15,000 PSI BASED ON TEST DATA REPORTS TVA-CEB-79-7 AND MA 2-79-1 ALLOHABLE SUPPORT PER AISC STRESS TENSION UP TO 0. 9Sy AND BENDING 0.7Su SMALLER OF 1.2Sy OR 0.7Su SAME AS PIPE SUPPORT OPERABILITY CRITERIA ALLONABLE SUPPORT PER AISC STRESS COMPRES-UP TO 0.9Sy SION, AXIAL AND BENDING 0.9Pt:g SAME AS PIPE SUPPORT OPERABILITY CRITERIA SHEAR PER AISC-UP TO 0 52Sy 0.42Su SMALLER OF 0.72Sy OR SAME AS PIPE SUPPORT OPERABILITY CRITERIA ALLOHABLE HELD STRESS SHEAR PER AISC UP TO O.SSy
.BASE METAL 0.42S BASE METAL BASED ON ASME III SUBSECTION NF,.
APPENDIX F, FOR SUPPORTS ALLOHABLE BOLT STRESS (TENSION)
PER AISC UP TO 0.56Sy OF BOLT GREATER OF 0.7Su OR Sy OF BOLT SAME AS PIPE SUPPORT OPERABILITY CRITERIA ALLOHABLE CONCRETE HEDGE TYPE-4 EXPANSION ANCHORS SHELL TYPE FACTOR OF SAFETY 5
FOR TENSION HEDGE AND SHELL 4
FOR SHEAR TYPE ALL TYPES 2
SAME AS PIPE SUPPORT OPERABILITY CRITERIA