ML20059K542
| ML20059K542 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 01/21/1994 |
| From: | Fenech R TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9402020146 | |
| Download: ML20059K542 (6) | |
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Robert A. Fenech 7
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January 21, 1994 I
I U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555 Gentlemen:
In the Matter of
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Docket Nos. 50-327' i
Tennessee Valley Authority
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50-328 SEQUOYAH NUCLEAR FIANT (SQN) - NRC INSPECTION REPORT NOS. 50-327, 328/93 REPLY TO NOTICE OF VIOLATION (NOV) 50-327,'328/93-52-02 i
j contains TVA's reply to R. V. Crlenjak's letter to Mark O. Medford dated December 23, 1993, which transmitted the subject NOV.
The violation involved procedures that were inadequate in that.they did not contein provisions to periodically inspect critical areas of the L-Units 1 and 2 steel containment vessels. -Enclosure 2 contains the list' of commitments.
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If you have any questions concerning this submittal please telephone _
l C. H. Whittemore at (615) 843-7210.
Sincerely,
/$b Robert A. Fenech i
Enclosure cc: See page 2
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U.S. Nuclear-Regulatory Commission-Page 2 EJanuary 21, 1994 d
cc (Enclosure):
Mr. D. E. LaBarge, Project Manager
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U.S. Nuclear Regulatory Commission 1
One White' Flint, North 11555 Rockville Pike Rockville, Maryland 20852-2739 Mr. Dave McGuire U.S. Nuclear. Regulatory Commission Region II P. O. Box 2257 Atlanta, Georgia 30301-2257 NRC Resident Inspector Sequoyah Nuclear Plant 2600 Igou Ferry, Road Soddy-Daisy, Tennessee' 37379-3624 Regional Administrator U.S. Nuclear Regulatory Commission Region Il 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323-2711
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ENCLOSURE 1 RESPONSE TO NRC INSPECTION REPORT NOS. 50-327, 328/93-52 R. V. CRLENJAK'S LETTER TO MARK 0. MEDFORD DATED DECEMBER 23, 1993 Viniatim_50-32Z,_328/23-12-02
" Technical Specification Section 6.8.1 requires, in part, that procedures shall be established, implemented, and maintained covering the activities recommended in Appendix A of Regulatory Guide 1.33, Revision 2, February 1978. Appendix A of. Regulatory Guide 1.33 includes procedures to perform.
surveillance requirements.
Implicit in these requirements is that the procedures be adequate.
"10 CFR 50, Appendix J, requires, in part, that a general inspection of the accessible interior and exterior surfaces of the containment structure be performed.
" Technical Specification 4.6.1.6 requires, in part, that a visual inspection of the exposed, accessible interior and exterior surfaces of the containment vessel be performed.
l "The procedures for Units 1 and 2 respectively, SI-254 and SI-254.2,.
CONTAINMENT VESSEL AND SHIELD BUILDING INTEGRITY VERIFICATION, implement the requirements of 10 CFR 50, Appendix J and Technical Specification Surveillance Requirement 4.6.1.6.
" Contrary to the above, prior to July 1993, SI-254 and SI-254.2 were inadequate, in that, they did not contain provisions to periodically inspectithe area of the containment liner which was covered by stainless steel flashing in the lower containment raceway.
This resulted in the failure of the licensee to, identify the existence of water accumulation, a
some containment liner degradation, and design inconsistencies.
"This is a severity level IV violation (Supplement 1)."
Reason _for_Yinjatina The reason for the violation is that there was a lack of sensitivity and aggressiveness regarding the. investigation of potential corrosion and degradation of the steel containment vessel (SCV).
10 CFR 50, Appendix J, " Primary Reactor Containment Leakage Testing for Water Cooled Power Reactors," requirements and corresponding TVA Sequoyah Nuclear Plant (SQN) Technical Specification Surveillance Requirement 4.6.1.6, " Containment Vessel Structural Integrity," are implemented by TVA SQN Surveillance Instructions SI-254 and SI-254.2.
These procedures and their inspection requirements have been reviewed and compared with methods used at other nuclear sites. The conclusion was o
'* that the procedures were adequate and met the regulatory requirements for complying with Appendix J inspections.
TVA recognizes that the SI-254 and SI-254.2 procedures did not adequately address the inspection of the SCVs in regard to corrosion problems.
The procedures mentioned in the notice of violation (NOV) were one logical place to have requirements for the inspection and identification of corrosion and possible. degradation of-the SCVs in the vicinity of the SCV and concrete floor interface.
However, these procedures were not developed and implemented to accomplish this. The intent of the procedures was to verify by a visual inspection that the SCV and shield building were leak-tight and met the structural integrity verification requirements required by technical specifications before performing a Type A containment leak-rate test, i.e., no unacceptable openings that would fail a leak-rate test. There were other activities such as housekeeping inspections and postmaintenance walkdowns of containment where corrosion and other types of degradation could have been identified.
Each time a question was raised or a potential problem was identified by another utility concerning containment integrity involving the potential for corrosion and/or degradation of the SCV, the issue was investigated at SQN, and each time the conclusion was reached that there was no degradation of the SQN SCV.
Therefore, the need for a proceduralized periodic inspection to specifically verify the integrity of the vessels in the vicinity of the SCV concrete floor interface with regard to corrosion degradation was never aggressively pursued.
Correctivl_Antions_Ihat Have Been Taken and thr._Ecaults Achieved In December, the procedures mentioned in the NOV were revised to increase the awareness of the personnel performing the-inspections regarding corrosion and SCV structural deterioration. This was accomplished by enhancing the information required to document the condition of the liner regarding indications of degradation'or structural deterioration. Unit 1 was inspected, using the revised version of the procedure, i.e., SI-254, Revision 6.
The findings were do'cumented, and each finding was subsequently evaluated. The conclusion was that the identified corrosion did not result in the degradation of the Unit 1 SCV or shield building.
The specific corrosion issue cited in the NOV involving the SCV at the concrete floor interf ace inside the SCV has been investigated by the Technical Programs and Perf ormance (TP&P) section, and the results have been documented in an incident investigation report (SQ 930304II). The report addresses the problems of water accumulation, minor SCV liner degradation, and design inconsistencies. The appropriate corrective actions to these problems will be tracked to completion by the incident investigation.
The need to heighten the sensitivity of management and personnel, in general, and especially towards issues that represent potential problems at SQN, has been recognized. Corrective actions were fonnulated in an effort to accomplish this.
These actions are described in the Site Improvement Plan and Postrestart Plan.
One result of these efforts was to f onnulate the TP&P section with a corrosion program group specifically assigned to address corrosion problems such as those leading up to the NOV described above.
Correcthte_. Actions _That Will be Taken to Avoid _EutvIc_J1olations A procedure will be developed and implemented requiring periodic inspections of the areas behind the stainless steel flashing where the SCV and concrete floor interface.
DaLc_.Ren IulLCapellance Mill be Achinyed TVA SQN will be in full compliance March 22, 1994.
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9 ENCLOSURE 2 COMMITMENT-i A procedure will be developed and implemented requiring inspections of-the areas behind the stainless steel flashing where the SCV and concret'e floor interface. This will be accomplished by March 22, 1994.
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