Headquarters Daily Report
MARCH 08, 2001
***************************************************************************
REPORT NEGATIVE NO INPUT
ATTACHED INPUT RECEIVED RECEIVED
HEADQUARTERS X
REGION I X
REGION II X
REGION III X
REGION IV X
PRIORITY ATTENTION REQUIRED MORNING REPORT - HEADQUARTERS MARCH 8, 2001
Licensee/Facility: Notification:
South Carolina Electric & Gas Co. MR Number: H-01-0017
Summer 1 Date: 03/08/01
Jenkinsville,South Carolina
Dockets: 50-395
PWR/W-3-LP
Subject: Part 21 Update - Terminal Shaft Binding in Woodward Governor EGB
Actuator
Reportable Event Number: 37788
Discussion:
On February 28, 2001, South Carolina Electric & Gas Company (SCE&G)
submitted a 10 CFR Part 21 report (see Event #37788 and NRC Morning
Report H-01-0015) concerning binding of the terminal shaft on a Woodward
Type EGB Governor/Actuator. The governor could not be set up to operate
properly following refurbishment by Engine Systems, Incorporated (ESI).
The staff contacted ESI and found that the governor in question had been
refurbished by Woodward Governor Company, under contract with ESI.
Woodward governors are used extensively in the nuclear power industry to
control the emergency diesel generators. However, these governors are
manufactured (and rebuilt) as commercial grade components by Woodward and
subsequently must be qualified for safety related applications by
individual licensees or third party dedicators with 10 CFR 50 Appendix B
quality assurance programs, such as ESI, B.F. Goodrich/Fairbanks Morse,
or Dresser-Rand.
SCE&G sent the failed EGB actuator to B.F. Goodrich/Fairbanks Morse for a
failure analysis, to get an independent assessment of its condition.
Fairbanks Morse found that there was binding of the terminal shaft and
misalignment of the terminal lever. Misalignment of the terminal lever
could cause governor instability. Fairbanks Morse determined that the
binding of the terminal shaft was caused by the use of clamping screws
that were 1/8-inch longer than those specified, which allowed the ends of
the screws to contact the power piston rod and bind it.
The NRC staff contacted Woodward and learned that the governor was
refurbished by a technician that was technically qualified but who had
not performed refurbishing work for a long time. Typically, only two
Woodward technicians perform refurbishment of EGB governors, and these
two technicians have been doing the refurbishments for many years.
Because of a large volume of work in 1999-2000, a third technician was
brought in to help out. As part of the refurbishment process, Woodward
installs an enhanced pin retainer bracket that is different from the
original bracket. This bracket was an engineering change designed in 1978
and has been in use for many years in the commercial and nuclear power
industry. The V.C. Summer EGB actuator had been in service for over 20
years and did not have the enhanced bracket installed until the 1999-2000
refurbishment. Woodward believes that the technician failed to properly
install the modified bracket. The engineering change notice for the
bracket states that new clamping screws should be used when installing
the new bracket. The new screws are shorter than the screws used in the
original bracket. Woodward was aware that use of the longer screws could
result in interference with the power piston rod. Woodward stated that a
note to use new screws was not included in the shop procedure that the
HEADQUARTERS MORNING REPORT PAGE 2 MARCH 8, 2001
MR Number: H-01-0017 (cont.)
technicians use to perform the refurbishments. The procedure simply
states that the bracket should be installed per the engineering change
notice. The experienced technicians were aware that the longer screws
could cause interference and would either install new screws or grind off
the long screws so that they would not protrude through the bracket.
Apparently, the third technician was not aware of the need to use the new
screws and did not consult the engineering change notice before
installing the enhanced bracket.
On a related note, New York Power Authority (NYPA), the Fitzpatrick
licensee, identified a problem with an EGB unit that developed loading
and speed problems. The EGB unit had been refurbished by Woodward under a
contract with ESI in June 2000. The licensee found that the pivot pin for
the speed droop lever backed out of its mounting holes and allowed the
lever to become misaligned. The licensee stated that retaining rings used
to hold the pivot pin in place were missing. The staff also learned that
South Texas Project identified an EGB unit with a missing retaining ring.
Woodward told the staff that the same technician that worked on the
Summer EGB unit also did the work on the Fitzpatrick and South Texas
Project units. Woodward also stated that another EGB unit refurbished by
this technician was found to have the retaining rings missing, but that
unit was identified before it was shipped out to the customer. The
technician no longer performs governor refurbishment work.
Woodward identified a total of seven EGB units that were refurbished by
the third technician: two units were purchased by Fitzpatrick, two were
purchased by Cooper Bessemer (a diesel generator manufacturer), and one
each went to South Texas Project, Turkey Point 3, and V.C. Summer. ESI
has contacted Cooper Bessemer to identify the sites to which those two
EGB units were shipped. ESI told the staff that it will issue a Part 21
report identifying the suspect EGB units by purchase order and serial
number, and will request that customers who have the suspect EGB units
return them to ESI for a complete tear-down inspection, reassembly, and
functional test to the Woodward specifications.
The detailed ESI Part 21 report will be posted on the NRC website at:
http://www.nrc.gov/NRC/PUBLIC/PART21/2001
Contact: David Skeen, NRR
(301)415-1174
E-mail: dls@nrc.gov
_
