ML18038B011
| ML18038B011 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 11/14/1994 |
| From: | Hebdon F Office of Nuclear Reactor Regulation |
| To: | Kingsley O Tennessee Valley Authority |
| Shared Package | |
| ML18038B012 | List: |
| References | |
| TAC-M90293 NUDOCS 9411170307 | |
| Download: ML18038B011 (6) | |
Text
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so UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, O. C. 20555 November 14, 1994 Hr. Oliver D. Kingsley, Jr.
President, TVA Nuclear and Chief Nuclear Officer Tennessee Valley Authority 6A Lookout Place 1101 Market Street Chattanooga, TN 37402-2801
SUBJECT:
BROWNS FERRY NUCLEAR PLANT UNIT 2 - SAFETY EVALUATION OF REVISED RELIEF RE(VEST SPT-4 (TAC NO. H90293)
Dear Hr. Kingsley:
By letter dated September 1,
1994, the Tennessee Valley Authority (TVA) requested relief from certain inservice inspection (ISI) requirements of Section XI of the American Society of Mechanical Engineers (ASHE) Boiler and Pressure Vessel Code for the Browns Ferry Nuclear Plant (BFN) Unit 2.
Specifically, TVA requested revision of relief request SPT-4, which had been granted by the NRC staff in a letter dated May 21, 1993.
Originally, TVA had committed to perform a VT-3 examination of leaking control rod drive housing cap screws during the next refueling outage.
TVA proposed a revision to SPT-4 to perform a VT-1 inspection of disassembled control rod drive (CRD) connections, with additional magnetic particle inspections, if necessary.
TVA's revised relief request SPT-4 was discussed in a telephone conversation with NRC staff representatives on September 26, 1994.
Following this discussion, TVA provided additional information on October 3,
- 1994, including a
new revision of relief request SPT-4, reflecting the additional information.
In part, TVA committed to inspect cap screws removed from CRD housing connections which were observed to be leaking at the end of the Unit 2 Cycle 7
fuel cycle.
During this inspection, TVA found several cap screws from leaking CRD housing connections and CRD housing connections disassembled for maintenance which showed indications of intergranular stress corrosion cracking
( IGSCC).
This discovery invalidated a portion of TVA's original justification for relief.
As a result, a further revision of SPT-4 was submitted by TVA on November 2,
1994.
This proposed SPT-4 revision consists of three parts, designated by TVA as items I, II, and III, respectively:
g 9
n of cap screws from CRD housing Igp ppIi". p'p)gQ IKpSPV (()I I.
TVA has requested relief from ASHE Code requirements to remove and inspect cap screws from CRD housings observed to be leaking at the beginning of a fuel cycle.
As an alternative, TVA proposes to inspect these cap screws during the next refuelin outa e.
In addition TVA proposes to perform a VT-1 examinatio "70029 9411170307 941114 PDR ADOCK 05000260 P
- 0. Kingsley connections removed for maintenance, with additional magnetic particle testing if necessary.
II.
TVA requests relief from the ASHE Code requirements to expand the cap screw sample examined during the BFN Unit 2, Cycle 7 outage.
TVA claims that since there is reasonable assurance of the continued satisfactory performance of the CRD housings, expanding this sample would result in unjustifiable personnel radiation exposure.
This relief is requested for one fuel cycle.
TVA has committed to replace all the remaining original design cap screws with an improved design during the next BFN Unit 2 refueling outage.
III.
TVA requests one-time relief from the ASHE Code requirements to inspect the original design cap screws removed during the next BFN Unit 2 refueling outage.
TVA claims this inspection is unnecessary, since all these cap screws will be replaced with a new cap screw design.
The NRC staff assessment of these requests is documented in the enclosed safety evaluation.
With regard to TVA's request for relief from ASHE Code requirements for visual inspection of cap screws from CRD housings leaking at the beginning of a fuel cycle, the staff believes that it is important to determine whether cap screw performance has deteriorated over the course of a fuel cycle.
Therefore, the staff requires that TVA perform an inspection at the end of a fuel cycle to determine whether any CRD housings are leaking.
The staff then requires TVA to inspect all cap screws from any leaking CRD housings.
The staff finds that the proposed alternative inspection, with the additional inspections required by the staff, provides an acceptable level of quality and safety.
The NRC staff has determined that the proposed alternativ'e, as modified by the additional staff requirements, is therefore authorized, pursuant to 10 CFR 50.55a(a)(3)(i).
With regard to TVA's request for relief from ASHE Code requirements for expansion of the cap screw sample during the BFN Unit 2 Cycle 7 outage, the staff finds that compliance with the ASME Code requirements would result in hardship without a compensating increase in the level of quality and safety.
The NRC staff has determined that relief from these requirements is therefore authorized, pursuant to 10 CFR 50.55a(a)(3)(ii).
This relief is granted on a
one-time basis for the BFN Unit 2 Cycle 7 outage only.
With regard to TVA's request for relief from ASHE Code requirements for examination of original design cap screws to be removed during the next BFN Unit 2 refueling outage, the staff finds that the proposed alternative provides an acceptable level of quality and safety.
The NRC staff has determined that the proposed alternative is therefore authorized, pursuant to 10 CFR 50.55a(a)(3)(i).
This relief is granted on a one-time basis, and applies only to the removal of the original design cap screws.
0
- 0. Kingsley Please contact Joe Williams at (301) 504-1470 if you have any questions regarding this topic.
Sincerely, original signed by Frederick J.
Hebdon, Director Project Directorate II-4 Division of Reactor Projects I/II Office of Nuclear Reactor Regulation Docket No. 50-260
Enclosure:
Safety Evaluation cc w/enclosure:
Distribution
.: Docket File
-'FN Reading R.
Zimmerman J. Zwolinski ACRS(4)
B. Boger, RII See next page PUBLIC W. Russell/F.
Miraglia R. Spessard L. Dudes G. Hill OC/LFDCB E. Sullivan S.
Varga J.
Lieberman E. Jordan OPA G. Tracy DOCUMENT NAME:
G:iBFNiSPT4REV,LTR To receive o copy of this document, lndlcote In the bosn C
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/94 OFFICIAL RECORD COPY l~ / r /94 tl / I't /94
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Mr. Oliver D. Kingsley, Jr.
Tennessee Valley Authority CC:
Mr. Craven Crowell, Chairman Tennessee Valley Authority ET 12A 400 West Summit Hill Drive Knoxville, TN 37902 Mr.
W.
H. Kennoy, Director Tennessee Valley Authority ET 12A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. Johnny H. Hayes, Director Tennessee Valley Authority ET 12A 400 West Summit Hill Drive Knoxville, TN 37902 Mr. 0. J. Zeringue, Sr. Vice President Nuclear Operations Tennessee Valley Authority 3B Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Dr. Mark 0. Medford, Vice President Engineering
& Technical Services Tennessee Valley Authority 3B Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. D.
E. Nunn, Vice President New Plant Completion Tennessee Valley Authority 3B Lookout Place 1101 Market Street Chattanooga, TN 37402-2801 Mr. R.
D. Machon, Site Vice President Browns Ferry Nuclear Plant Tennessee Valley Authority P.O.
Box 2000
- Decatur, AL 35602 General Counsel Tennessee Valley Authority ET 11H 400 West Summit Hill Drive Knoxville, TN 37902 BROWNS FERRY NUCLEAR PLANT Mr. Roger W. Huston, Manager Nuclear Licensing and Regulatory Affairs Tennessee Valley Authority 4G Blue Ridge 1101 Market Street Chattanooga, TN 37402-2801 Mr. T.
D. Shriver Nuclear Assurance and Licensing Browns Ferry Nuclear Plant Tennessee Valley Authority P.O.
Box 2000
- Decatur, AL 35602 Mr. Pedro Salas Site Licensing Manager Browns Ferry Nuclear Plant Tennessee Valley Authority P.O.
Box 2000
- Decatur, AL 35602 TVA Representative Tennessee Valley Authority 11921 Rockville Pike, Suite 402 Rockville, MD 20852 Regional Administrator U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, NW., Suite 2900
- Atlanta, GA 30323 Mr. Leonard D. Wert Senior Resident Inspector Browns Ferry Nuclear Plant U.S. Nuclear Regulatory Commission 10833 Shaw Road
- Athens, AL 35611 Chairman Limestone County Commission 310 West Washington Street