ML20099D641
| ML20099D641 | |
| Person / Time | |
|---|---|
| Site: | Bellefonte  |
| Issue date: | 10/25/1984 |
| From: | Mills L TENNESSEE VALLEY AUTHORITY |
| To: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-84, REF-PT21-84-006-000, REF-PT21-85-006-000 PT21-85-006-000, PT21-85-6, NUDOCS 8411200467 | |
| Download: ML20099D641 (2) | |
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-TENNECZEE VALLEY' AdTHORITY CH ATTANOOGA.- 1 ENNESSEE 374o1 400 Chestnut Street Tower II 6
BLRD-50-438/81 -
BLRD-50-439/81-58
'U.S. Nuclear Regulatory Commission
-Region II Attn:
Mr. James P. O'Reilly, Regional. Administrator 101 Marietta Street, NW, Suite 2900
' Atlanta, Georgia 30323
Dear Mr. O'Reilly:
BELLEFONTE NUCLEAR PLANT UNITS 1 AND 2 - REACTOR COOLANT SYSTEM SUPPORTS AND RESTRAINTS - BOLT TORQUES - BLRD-50-438/81-56, BLRD-50-439/81 SEVENTH INTERIM REPORT The : subject deficiency was initially mported to NRC-0IE Inspector R. V. Crlenjak on August 24, 1981 in accordance with 10 CFR 50.55(e) as NCR BLN NEB 8111. This was followed by our interim reports dated September 24 and December 7,1981; March 10, June 7, and December 13, 1982; and June 29, 1983 Enclosed is our seventh interim report. We expect to submit our next report on er about June 29, 1985. We consider 10 CPR Part 21 applicable to this deficiency.
If you have any questions concerning this matter, please get in touch with R. H. Shell at FTS 858-2688.
Very truly yours, TENNESSEE VALLEY AUTHORITY L. M. Mills", Manager Nuclear Licensing Enclosure oc (Enclosure):
Mr. Richard C. DeYoung, Director Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, - D.C.
20555 Mr. H..B. Barkley 205 Plant Project Services
'P.O. Box 10935 Lynchburg, Virginia 24505 Records Center r--
Institute of Nuclear Power Operations MICIAL COPY 1100 circle 75 Parkway, Suite 1500
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Atlanta, Georgia 30339
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' b _ 2, 8411200467 841025 PDR ADOCK 05000438 I
S PDR An Equal Opportunity Employer
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ENCLOSURE
- BELLEFONTE NUCLEAR PLANT UNITS 1 'AND 2 REACTO'R COOLANT SYSTEM SUPPORTS AND RESTRAINTS - BOLT TORQUES _
,NCR BLN-NEB 8111..
BLRD-50-438/81-56, BLRD-50-439/81-58
~10 CFR 50.55(e).
SEVENTH INTERIM REPORT
' Description of Deficiency Babcock & Wilcox (B&W), Lynchburg, Virginia,.specified ASME SAS40 Class I~
1and:2 material and a preload of 70 percent of ultimate tensile strength for
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many 'of the Reactor Coolant System (RCS) anchor. bolts for supports and -
restraints.. These materials have a minimum yield strength of 150 kai and 140 ksi, respectively. Recently, it. has been documented that stress corrosion cracking-(SCC) is a potential-failure mode for high yield st.aength (> 120 kai). low alloy steel bolting material subjected to-appreciable steady state loads (generally preload in the case of supports and restraints) and typical reactor containment corrosive environments (humid air or borated water on occasion) ' for extended periodc of time.
B&W notified TVA (in an August 19,1981_ B&W letter to TVA) that' they had' reported to the'NRC, under the requirements of 10 CFR Part 21, concerns that B&W has with regard to stress corrosion cracking of high strength bolting material.
Interim Progress The RCS support and restraint bolting material is ASME SA540 Classes 1 -_and 2 with a minimum specified-yield strength of 150 kai and 140 ksi, respectively. Utilizing the component support bolting screening criteria established by the Atomic Industrial Forum / Metals Property Council
( AIF/MPC) Task Group on Bolting (submitted to the NRC as Appendix I, Task 14, of the Task Group's bolting program enclosed with Richard M. Eckert's letter from the AIF to R. H. Vollmer dated July 19, 1983) results in the conclusion that generic evaluation of the support and restraint bolting is not warranted as the minimum specified -yield strength of the material is not greater than 150 ksi. Also, since TVA has not experienced failures of the support and restraint bolting, case-by-case evaluation via a plant-t specific plan is similarly not warranted.
However, since the mininum specified yield strength of the SA540 class 1 bolting is at the dividing line according to the screening criteria,_ TVA will perform a case-by-case review of the class 1 bolting in accordance with the following rationale:
Step 1 - A certified material test report (CMTR) will be located for each heat of SA540 class 1 used in RCS support and restraint bolting
-applications.
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St'n 2 - In light cf tha relativcly demanding nature cf th3 SA540 mat:rini rpecific0ti n' (i.e., miniasm cnd maximum hardn ss mquirementc, htedn ss testing frequency which is mgarded as sufficient' to provide statistically significant information, impact testing requirements, etc.) it has been judged that some exemption of this material from evaluation of stress corrosion cracking (SCC) susceptibility is rer.sonable and may be based on CMrR resiew. This myiew will follow the seven-point CMTR review criteria established by APTECH Engineering Services. Materials which meet the-criteria will be exempt from further review.
Step 3 - Material which does not meet the requirements of step 2 will be evaluated considering the results of EPRI's Generic Joint Integrity Program (reference J. V. Williams letter to R. Vollmer dated June 6,1984, which provided the NRC with an update on the AIF/MPC Task Group Program on bolting).
A need for fbrther action associated with this nonconf ormance report will be determined following completion of this myiew and TVA will provide additional information at that time.
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