ML20215K167
| ML20215K167 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/28/1986 |
| From: | Gridley R TENNESSEE VALLEY AUTHORITY |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| NUDOCS 8610280007 | |
| Download: ML20215K167 (3) | |
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' r_A & C TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNESSEE 37401
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- O c CNG / f/l.E 00 AUG 281986 U.S. Nuclear Regulatory Commiscion Region II ATTN:
Dr. J. Nelson Grace, Regional Administrator 101 Marietta Street, NW, Suite 2900 Atlanta, Georgia 30323
Dear Dr. Grace:
BROWNS FERRY NUCLEAR PLANT UNITS 1, 2, AND 3 - CABLE PULLING SPECIFICATIONS On June 24, 1986, the. Browns Ferry Site Director and other TVA staff met with your regional st a ff concerning cable pulling practices and specifications utilized at Browns Ferry. The enclosure to this letter summarizes the TVA position on this issue and plans for future cable pulling activities presented in the meeting.
Should you have further questions on this subject, please get in touch with M. J. May at Browns Ferry (205) 729-3566.
Very truly yours, TENNESSEE VALLEY AUTHORITY
/
R. L. Gridley Director Nuclear Safet and Licensing Enclosure cc (Enclosure):
Mr. James Taylor, Director (Enclosure)
Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, D.C.
20555 Mr. R. J. Clark Browns Ferry Project Manager U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue Bethesda, Maryland 20814 8610280007 860020 PDR ADOCK 05000259 h() (
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An Equal Opportunity Employer
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ENCLOSURE
SUMMARY
OF TVA PRESENTATION CABLE PULLING SPECIFICATIONS FOR BROWNS FERRY NUCLEAR PLANT (BFN) j JUNE 24, 1986 i
The BFN Site Director, TVA licensing, and other members of BFN management met with regional NRC inspectors and management on June 24, 1986 to discuss the BFN cable pulling specifications status. The following is a summary of TVA's presentation made at that meeting and our current status.
Background
The specifications for cable pulling and conduit installation at BFN were Construction Specifications G-3 and G-4.
These specifications were utilized both for original construction and subsequent modifications to the facility.
All other TVA nuclear facilities (Sequoyah (SQN), Watts Bar (WBN), and Bellefonte (BLN)) utilized standards G-38 and G-40.
Construction Specifications G-38 and G-40 were revised in September and October of 1985 to address a generic concern regarding cable sidewall pressure j
for cable pulling practices. These revised specifications were directly i
applicable to SQN, WBN, and BLN Nuclear Plants which already used G=38 and G-40 as standards.
Additional considerations were necessary regarding the transition from G-3 and G-4 to G-38 and G-40 on BFN, particularly with regard to application of the newer standards to as-built plant conduit configurations. A significant problem involved the fact that G-38 cable pulling specifications are not universally compatible with the physical configurations of conduit previously installed under G-3.
In late 1985, unit 2 was in a major refueling and modification outage and many conduit installations had been installed using G-3.
Modification activities on units 1 and 3 were minimal with resumption of major work not anticipated for a lengthy time.
The following implementation strategy for the orderly transition to the G-38
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and G-40 specifications at BFN was initially proposed by TVA:
1.
Utilize G-3 and G-4 to complete remaining unit 2 outage work for which designs had been issued before January 15, 1986.
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2.
Incorporate G-38 and G-40 requirements into unit 2 outage work for which j
designs had been issued on or after January 15, 1986.
3.
G-38 and G-40 would be utilized for the unit 2 cable replacement activities in the drywell.
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4 G-38 and G-40 would be used for the future modification activities on units 1 and 3 when work resumed.
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s This approach was based on the following reasons:
As of January 15, 1986, only a relatively small amount of work on unit 2 remained to finish the design changes issued before that date. For consistent and traceable documentation, it was logical to complete the work in progress using the same specifications (G-3/G-4) under which the work was started.
TVA was in the process of demonstrating the acceptability of past cable pulling practices by conducting several verification and testing programs, including pull tests on cables. There is a high confidence level that these test. programs will show the conservatisms inherent in the G-3 and G-4 procedures.
Current Status It was decided to fully complete the transition to the new installation standards. Specifically, G-38 and G-40 would be applied to future cable and conduit installations regardless of design issuance dates. Modification and maintenance procedures are being revised to reflect the appropriate requirements of G-38 and G-40.
Modification activities will resume following the completion of the instruction changes and training of personnel. Certain cable and conduit activities such as installation of telephone cables, and electrical installations in service buildings will not be governed by G-38/G-40.
Where maintenance would require extensive modifications to meet G-38 and G-40, maintenance may be performed to the original requirements, and such exceptions will be properly justified and documented.
If these
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exceptions cannot be justified, G-38 and G-40 will be the g
a specifications.
Several TVA technical integrity verification programs are presently underway.
These are scheduled to be completed in late 1986. These programs include verification of cable adequacy with regard to: (1) ampacity (2) pulling tension / sidewall pressure (3) environmental qualification, and (4) electrical ca'lcula tions.
Moreover, tests have been conducted to establish allowable sidewall pressure limits. preliminary results indicate that the installed cable is capable of reliable operation at several times the sidewall pressure specified by the vendors. This conservatism is expected to demonstrate the integrity of existing cable installed under G-3 and G-4 at BFN.
If any of the programs should indicate cases of inadequate cable conditions, new cable will l
be installed using the revised installation instructions.
0657c l
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