ML19329B148
| ML19329B148 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 12/15/1976 |
| From: | Heishman R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| Shared Package | |
| ML19329B143 | List: |
| References | |
| NUDOCS 8001300722 | |
| Download: ML19329B148 (2) | |
See also: IR 05000346/1976018
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UNITED STATES
NUCLEAR REGULATORY COMMISSION
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REGloN lit
GLEN ELLYN. BLLINCIS 60137
December 15, 1976
Karl V. Seyfrit, Chief, Technical Assistance Branch
Office of Inspection and Enforcement, Headquarters
SUPPORT OF CONTROL AND INSTRUMENT CABLES ROUTED IN VERTICALLY INSTALLED
CONDUIT - (A/I F30248H)-
TOLEDO EDISON COMPANY - DAVIS-BESSE UNIT 1 (DOCKET No. 50-346)
Section 300-19 of.the National Electric Code (NEC) requires that
" Conductors in vertical raceways shall be supported.
One cable
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support shall be provided at the top of the vertical raceway or as
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close to the top as practical, plus a support for each interval of
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spacing as specified in Table 300-19(a)." Spacings for conductor
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supports and support methods are also provided.
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The Toledo Edison Company (TECO) in their Final Safety Analysis
Report for Davis-Besse Unit No. 1, committed to use the NEC for
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Class 1E design and installation.
TECO's installation specification
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electrical inspection, it was noted :. hat Davis-Besse installations
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appropriately references Section 300-19 of the NEC. During a special
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did not conform to the above stated criteria.
The disposition by
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TECO of the finding was to revise the installation specification.
Originally, the specification read: "Verti. cal. conduit. risers of more
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.than 20 feet shall be provided with spproved cable clamps or supports."
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As revised, it reads': "All vertical conduit risers carrying' power
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cables shall have the provision for supporting'the cables in accordance
with the .1971 National Electric Code, Section_300,-19_.
All vertical
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conduit risers carrying control or instrumentation cable, which are
over 20 feet in length and terminate at the upper end, shall have the
cables restrained by wedge grommets or split Kellum Grips at the upper
end to prevent strain on the terminals." -
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IE:III identified the specification change as inappropriate and a
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deviation from previous commitments (IE Inspection Report _No.
050-346/76-18). The basis for this action was:
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The arbitrary split in requirements between power and control
instrumentation cable;
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The liberal requirement of " terminated at the upper end"; and
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Karl V. Seyfrit
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December 15, 1976
3.
The lack of assurance that the unsupported cables will maintain
all safety, physical, and electrical characteristics and not
sustain damage from elongation, expansion, vibration, abrasion,
or fraying over the design 40-year plant life.
TECO disagreed with the deviation notice and contend, in their
response letter dated November 24, 1976, that the specification
change is considered to be appropriate, in accordance with good
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engineering practice, and meets the intent of the NEC. Further,
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TECO contends that support for control and instrument cable is
solely "for the purpose of termination protection and not related
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to conductor tension strain."
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Answers to the following questions are specifically requested:
1.
Is TECO's specificacian revisica appropriate,
i.e.,
in keeping
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with the inecnt of NEC Section 300-19?
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2.
Is the revised design acceptable for support of instrument
control cables? If not, what would be considered an acceptable
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design?
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Should you have any questions concerning this matter, please contact
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Mr. D. W. Hayes or Mr. F. J. Jablonski.
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R. F. Heish=an, Chief
Reactor Construction and
Engineering Support Branch
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Attachments:
1. Ltr dtd 11/24/76
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Lowel E. Roe to James G. Keppler
2. Ler dtd 12/15/76
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R. F. Heishman to TECO
cc:
G. W. Roy, IE:HQ, w/ attachments
J. G. Keppler,w/o attachments
D. W. Hayes, w/o attachments
C. C. Williams, w/o attachments
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