IE Circular No. 80-23, Potential Defects in Beloit Power Systems Emergency Generators
SSINS No.: 6830
Accession No.:
8008220243
IEC 80-23
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D. C. 20555
October 31, 1980
IE Circular No. 80-23: POTENTIAL DEFECTS IN BELOIT POWER SYSTEMS EMERGENCY
GENERATORS
BACKGROUND
This circular addresses a potential deficiency involving the field leads of
generators manufactured by Beloit Power systems. It is known that the
subject generators have been coupled with Fairbanks Morse diesel engines for
use in nuclear power facilities; however, it is not known whether they have
been coupled with other diesel engines for such use. Accordingly, the intent
of this circular is to notify all nuclear power facilities of the potential
defect and to assure that appropriate remedial actions are taken, if needed.
The Nuclear Regulatory Commission was first informed of the potential defect
by a phone call from Mr. R. H. Beadle of the Fairbanks Morse Engine Division
of Colt Industries to Mr. D. W. Hayes of Region III on September 19, 1980.
On September 20, 1980, a conference call was held between the NRC Duty
Officer, personnel from Prairie Island Nuclear Power Station, Mr. Beadle of
Fairbanks Morse, and Mr. C. Evenson of Beloit Power Systems, the principal
spokesman. The purpose of this call was to describe an inspection method
which Prairie Island personnel could use to examine the field lead
assemblies of their generators for the potential defect. (We have since been
informed by the Resident Inspector that the field lead assemblies of the
Prairie Island generators did not have the suspected defects.)
In order to disseminate this information on a timely basis, the NRC Duty
Officer at Bethesda called those operating facilities which he knew were
using the suspect generators on September 20 and 21, 1980. The information
conveyed included a description of the potential defect and a description of
the aforementioned inspection method. The operating facilities called were:
FACILITY NO. OF UNITS
Calvert Cliffs 1 and 2 3
Crystal River 3 2
Hatch 1 and 2 5
Duane Arnold 2
North Anna 1 and 2 4
Millstone 1 and 2 3
Robinson 2 2
Prairie Island 2
Vermont Yankee 2
Peach Bottom 2 and 3 4
Arkansas Nuclear One, Unit 2 2
.
IEC 80-23
October 31, 1980
Page 2 of 3
These phone calls were subsequently followed up with a Part 21 Report dated
September 22, 1980 from Mr. J. M. Moriarty, Manager, Utility Sales,
Fairbanks Morse Engine Division. Information conveyed in the Part 21 Report
included the following excerpt
"A Beloit Power Systems generator in commercial service at Sitka,
Alaska lost its field because a lead between the collector rings and
the field coils shorted to the rotor and burned in two pieces at the
point of the short. Subsequent examination of another generator of
identical design at the same installation showed frayed insulation at a
clamp (same location as the burn through) which secures the lead to the
rotor. This unit was operating satisfactorily but if the insulation
damage were to progress the possibility of grounding the lead to the
rotor exists."
"To determine if the problem might exist at other locations our chief
electrical engineer was sent to Provo, Utah which has four generators
of identical design. He has reported by phone that two of the four at
Provo have frayed insulation at the clamp but that there was no
indication of loss of field."
"Concurrent with, our inspection at Provo, Beloit Power Systems was
asked to evaluate the cause of frayed insulation and also if any other
generators might have the same problem. Their verbal report to us is
that the cause of fraying is poor workmanship in installation of the
clamps and that there are other generators of identical design in this
area. Specifically the eight generators shipped to Limerick
(Philadelphia Electric) are of the identical design in the area where
poor workmanship is known to have caused a problem."
"Our plan is to inspect the Limerick generators and repair any poor
workmanship which may be found. Beloit Power Systems also reports
verbally that the design in this area for 5 and 6 frame alternators has
been similar for a number of years and it is therefore possible that
the problem may extend to operating units."
RECOMMENDED ACTIONS FOR HOLDERS OF CONSTRUCTION PERMITS OR OPERATING
LICENSES:
1. Determine whether or not your facility uses emergency generators
manufactured by Beloit Power Systems, having frame sizes 5 or 6, as
part of the onsite emergency power system; if not, you need not pursue
this matter further.
2. If your facility uses generators manufactured by Beloit Power Systems
you should inspect the connections between the collector rings and the
field coils in the field lead assemblies of the generators for frayed
insulation at the clamps and make needed repairs per the enclosed
instruction sheet, "Inspection Procedures for Generator Field Leads".
The inspections should be completed as soon as practical and conducted
within the constraints of the Technical Specifications.
3. If the inspection reveals the need for repair or dressing of the leads,
said repair should be initiated at operating facilities as soon as
practicable after the need has been determined but no later than ten
(10) days thereafter, provided the unit is capable of performing its
function
.
IEC 80-23
October 31, 1980
Page 3 of 3
without the repair. Otherwise, the repair should be initiated
immediately after the need has been identified. Needed repair work
should be coordinated with Beloit Power Systems as stated in the
inspection procedure.
4. If the inspection reveals the need for repair or dressing of leads at
facilities holding Construction Permits, said repair should be
initiated at the licensee's earliest convenience and coordinated with
Beloit Power Systems.
Enclosure:
"Inspection Procedure for
Generator Field Leads"
Page Last Reviewed/Updated Tuesday, March 09, 2021