Information Notice 1985-68, Diesel Generator Failure at Calvert Cliffs Nuclear Station Unit 1: Difference between revisions

From kanterella
Jump to navigation Jump to search
(Created page by program invented by StriderTol)
(Created page by program invented by StriderTol)
 
(3 intermediate revisions by the same user not shown)
Line 3: Line 3:
| issue date = 08/14/1985
| issue date = 08/14/1985
| title = Diesel Generator Failure at Calvert Cliffs Nuclear Station Unit 1
| title = Diesel Generator Failure at Calvert Cliffs Nuclear Station Unit 1
| author name = Jordan E L
| author name = Jordan E
| author affiliation = NRC/IE
| author affiliation = NRC/IE
| addressee name =  
| addressee name =  
Line 14: Line 14:
| page count = 4
| page count = 4
}}
}}
{{#Wiki_filter:SSINS No.: 6835IN 85-68UNITED STATESNUCLEAR REGULATORY COMMISSIONOFFICE OF INSPECTION AND ENFORCEMENTWASHINGTON, D.C. 20555August 14, 1985IE INFORMATION NOTICE NO. 85-68: DIESEL GENERATOR FAILURE AT CALVERTCLIFFS NUCLEAR STATION UNIT 1
{{#Wiki_filter:SSINS No.: 6835 IN 85-68 UNITED STATES
 
NUCLEAR REGULATORY COMMISSION
 
OFFICE OF INSPECTION AND ENFORCEMENT
 
WASHINGTON, D.C. 20555 August 14, 1985 IE INFORMATION NOTICE NO. 85-68:   DIESEL GENERATOR FAILURE AT CALVERT
 
CLIFFS NUCLEAR STATION UNIT 1


==Addressees==
==Addressees==
:All nuclear power reactor facilities holding an operating license (OL) or aconstruction permit (CP).
:
All nuclear power reactor facilities holding an operating license (OL) or a
 
construction permit (CP).


==Purpose==
==Purpose==
:This information notice is provided to alert licensees of a potentially signif-icant safety problem involving cracked interpolar connecting bars that connectthe damper circuit of each rotor pole to the damper circuit of the adjacentrotor pole of the emergency diesel generator.It is suggested that recipients review this information for applicability totheir facilities and consider actions, if appropriate, to preclude similarproblems at their facilities. However, suggestions contained in this informa-tion notice do not constitute NRC requirements; therefore, no specific actionor written response is required.
:
This information notice is provided to alert licensees of a potentially signif- icant safety problem involving cracked interpolar connecting bars that connect
 
the damper circuit of each rotor pole to the damper circuit of the adjacent
 
rotor pole of the emergency diesel generator.
 
It is suggested that recipients review this information for applicability to
 
their facilities and consider actions, if appropriate, to preclude similar
 
problems at their facilities. However, suggestions contained in this informa- tion notice do not constitute NRC requirements; therefore, no specific action
 
or written response is required.


==Description of Circumstances==
==Description of Circumstances==
:On May 14, 1985, Calvert Cliffs Unit 1 was shut down for refueling. An overspeedtest on the No. 11 emergency diesel generator (EDG) was initiated with thegenerator not connected to its essential bus. During the test, plant personnelwho were stationed in the proximity of the EDG* heard loud, metallic rappingsounds coming from the generator section of the EDG and immediately terminatedthe overspeed test. Examination of the generator revealed that insulation onthe stator windings had been rubbed and abraded to the point where one statorwinding had been exposed. Further examination determined the cause of thefailure to be a broken interpolar connecting bar on the rotor. The bar initiallyhad broken free on one end and damaged the stator windings. Because thegenerator was not connected to its essential bus, electrical field*Calvert Cliffs is a 2-unit PWR station with three EDGs that are designated asfollows: Unit 1 (EDG 11), Unit 2 (EDG 21), and shared (EDG 12).8508120603 IN 85-68August 14, 1985 excitation had not been applied and no electric arcing occurred when the statorwindings were damaged. The damaged generator was replaced with a spare genera-tor and a detailed investigation was undertaken involving the vendor, LouisAllis, and the licensee.A metallurgical analysis on the failed interpolar connecting bar determined thepredominant cause of failure to be high stresses resulting from periodiccentrifugal loading. To a lesser degree, bending of the connecting bar, duringinitial installation, and thermal expansion also were considered to be contrib-uting factors in the failure. The licensee reports that the analysis indicatedthe problem was of a design nature and not the result of a material defect.Radiographic testing on the damaged generator showed several cracks in theremaining interconnecting bars.The investigation into the generator design determined that the interpolarconnections between rotor poles are not necessary (a) if the EDGs are notoperated in parallel, which could cause power pulsations between units, and (b)if the plant is operating with a balanced three-phase electrical load. CalvertCliffs does not operate its EDGs in parallel with each other. Analysis showsthat the potential three-phase electrical load unbalance factor (i.e.,single-phase load) does not exceed 10% of the emergency three-phase load;therefore, it is not considered a concern. Consequently, the licensee initiateda program to remove the interpolar connecting bars from the three EDGs inservice at Calvert-Cl-iffs Units 1 and 2.On the basis of these findings, the licensee removed EDG No. 21 from Unit 2service on May 26, 1985 to determine if the interpolar connections on that EDGwere degraded in a similar manner. Test results indicated cracks were evident.On this basis, the EDG No. 12 (which applies emergency power to either Units 1or 2) was declared inoperable. Under this set of conditions, Calvert CliffsUnit 2, which was operating at 100% full power, started shutting down. Inorder to continue power operation of Unit 2, the replacement EDG from Unit 1was connected and aligned to Unit 2 to provide the necessary emergency powersource and the shutdown was terminated.The licensee's corrective action, to terminate the limiting condition foroperation, discussed above, involved the immediate removal of the interpolarconnections from EDGs 12 and 21. Postmodification qualification testing,conducted on both EDGs, proved to be satisfactory.The licensee's longer term corrective action plans are to remove the interpolarconnections from the replacement (spare) EDG.Discussion:Typically, a diesel generator that employs the continuous damper circuit design(i.e., using interpolar connecting bars) uses 16 connecting bars. These barsare installed so that each of the eight rotor poles on the generator has twoconnecting bars, one installed on the front and one on the back of each rotorpole. Noncontinuous damper circuit design does not employ interpolar connec-tions between the damper circuits on the rotor pole IN 85-68August 14, 1985 The safety concern of this event is the common cause failure mechanism ifsimilar cracked connecting bars exist on all diesel generators at a nuclearpower plant (as was the case at Calvert Cliffs). Cracked connecting bars canlead to a condition that adversely affects the operating voltages which arenecessary to operate essential equipment during accident conditions.Because of the generic implications of the Calvert Cliffs event, the vendor,Louis Allis, issued a 10 CFR 21 report on the potential problem to the NRC onMay 21, 1985. A followup letter, dated May 29, 1985, from Louis Allis to theNRC, briefly discussed the problem and identified other facilities that usesimilar Louis Allis generator units. Colt Industries also forwarded a LouisAllis report dated June 3, 1985, that identified the major cause for interpolarconnecting bars cracking and provided a basis for requesting removal of theinterconnecting bars from similarly designed generators in service at otherfacilities. The June 3, 1985 report from Louis Allis to Colt Industries alsowas sent to end-users of the Louis Allis generator units.As a result of the early notifications discussed above, the licensees of TMI/1,Vermont Yankee, and Peach Bottom Units 2 and 3 all report that they have eitherremoved the interpolar connections or have established plans to have themremoved from the affected generator units in service at their facilities.Although no similar interpolar connecting bar failures have been reported,related to other generator units, generators supplied by manufacturers otherthan Louis Allis may have similar design features.Additionally, licensees are reminded that if corrective actions are taken toresolve observed degradation of interpolar connecting bars this action shouldbe reported to the NRC using the existing reporting requirements specified in10 CFR 50.72 and 10 CFR 50.73.No specific action or written response is required by this notice. If you haveany questions about this matter, please contact the Regional Administrator ofthe appropriate Regional Office or this office.A/.Edward.L. ordan, DirectorDivision of Emergency PreparednessandlEngineering ResponseOffice'of Inspection and Enforcement
:
On May 14, 1985, Calvert Cliffs Unit 1 was shut down for refueling. An overspeed
 
test on the No. 11 emergency diesel generator (EDG) was initiated with the
 
generator not connected to its essential bus. During the test, plant personnel
 
who were stationed in the proximity of the EDG* heard loud, metallic rapping
 
sounds coming from the generator section of the EDG and immediately terminated
 
the overspeed test. Examination of the generator revealed that insulation on
 
the stator windings had been rubbed and abraded to the point where one stator
 
winding had been exposed. Further examination determined the cause of the
 
failure to be a broken interpolar connecting bar on the rotor. The bar initially
 
had broken free on one end and damaged the stator windings. Because the
 
generator was not connected to its essential bus, electrical field
 
*Calvert Cliffs is a 2-unit PWR station with three EDGs that are designated as
 
follows: Unit 1 (EDG 11), Unit 2 (EDG 21), and shared (EDG 12).
 
8508120603
 
IN 85-68 August 14, 1985 excitation had not been applied and no electric arcing
 
occurred when the stator
 
windings were damaged. The damaged generator was replaced
 
with a spare genera- tor and a detailed investigation was undertaken involving
 
the vendor, Louis
 
Allis, and the licensee.
 
A metallurgical analysis on the failed interpolar connecting
 
predominant cause of failure to be high stresses resulting       bar determined the
 
from periodic
 
centrifugal loading. To a lesser degree, bending of
 
the connecting bar, during
 
initial installation, and thermal expansion also were
 
considered to be contrib- uting factors in the failure. The licensee reports that
 
the analysis indicated
 
the problem was of a design nature and not the result
 
of a material defect.
 
Radiographic testing on the damaged generator showed
 
several cracks in the
 
remaining interconnecting bars.
 
The investigation into the generator design determined
 
that the interpolar
 
connections between rotor poles are not necessary (a)
                                                        if the EDGs are not
 
operated in parallel, which could cause power pulsations
 
between units, and (b)
if the plant is operating with a balanced three-phase
 
electrical load. Calvert
 
Cliffs does not operate its EDGs in parallel with each
 
other. Analysis shows
 
that the potential three-phase electrical load unbalance
 
factor (i.e.,
single-phase load) does not exceed 10% of the emergency
 
three-phase load;
therefore, it is not considered a concern. Consequently, the licensee initiated
 
a program to remove the interpolar connecting bars from
 
the three EDGs in
 
service at Calvert-Cl-iffs Units 1 and 2.
 
On the basis of these findings, the licensee removed
 
EDG No. 21 from Unit 2 service on May 26, 1985 to determine if the interpolar
 
connections on that EDG
 
were degraded in a similar manner. Test results indicated
 
cracks were evident.
 
On this basis, the EDG No. 12 (which applies emergency
 
power to either Units 1 or 2) was declared inoperable. Under this set of conditions, Calvert Cliffs
 
Unit 2, which was operating at 100% full power, started
 
shutting down. In
 
order to continue power operation of Unit 2, the replacement
 
EDG from Unit 1 was connected and aligned to Unit 2 to provide the necessary
 
emergency power
 
source and the shutdown was terminated.
 
The licensee's corrective action, to terminate the limiting
 
condition for
 
operation, discussed above, involved the immediate removal
 
of the interpolar
 
connections from EDGs 12 and 21. Postmodification qualification
 
conducted on both EDGs, proved to be satisfactory.                     testing, The licensee's longer term corrective action plans are
 
to remove the interpolar
 
connections from the replacement (spare) EDG.
 
Discussion:
Typically, a diesel generator that employs the continuous
 
damper circuit design
 
(i.e., using interpolar connecting bars) uses 16 connecting
 
bars. These bars
 
are installed so that each of the eight rotor poles
 
on the generator has two
 
connecting bars, one installed on the front and one
 
on the back of each rotor
 
pole. Noncontinuous damper circuit design does not
 
employ interpolar connec- tions between the damper circuits on the rotor poles.
 
IN 85-68 August 14, 1985 The safety concern of this event is the common cause failure mechanism if
 
similar cracked connecting bars exist on all diesel generators at a nuclear
 
power plant (as was the case at Calvert Cliffs). Cracked connecting bars can
 
lead to a condition that adversely affects the operating voltages which are
 
necessary to operate essential equipment during accident conditions.
 
Because of the generic implications of the Calvert Cliffs event, the vendor, Louis Allis, issued a 10 CFR 21 report on the potential problem to the NRC on
 
May 21, 1985. A followup letter, dated May 29, 1985, from Louis Allis to the
 
NRC, briefly discussed the problem and identified other facilities that use
 
similar Louis Allis generator units. Colt Industries also forwarded a Louis
 
Allis report dated June 3, 1985, that identified the major cause for interpolar
 
connecting bars cracking and provided a basis for requesting removal of the
 
interconnecting bars from similarly designed generators in service at other
 
facilities. The June 3, 1985 report from Louis Allis to Colt Industries also
 
was sent to end-users of the Louis Allis generator units.
 
As a result of the early notifications discussed above, the licensees of TMI/1, Vermont Yankee, and Peach Bottom Units 2 and 3 all report that they have either
 
removed the interpolar connections or have established plans to have them
 
removed from the affected generator units in service at their facilities.
 
Although no similar interpolar connecting bar failures have been reported, related to other generator units, generators supplied by manufacturers other
 
than Louis Allis may have similar design features.
 
Additionally, licensees are reminded that if corrective actions are taken to
 
resolve observed degradation of interpolar connecting bars this action should
 
be reported to the NRC using the existing reporting requirements specified in
 
10 CFR 50.72 and 10 CFR 50.73.
 
No specific action or written response is required by this notice. If you have
 
any questions about this matter, please contact the Regional Administrator of
 
the appropriate Regional Office or this office.
 
A/
                                  .Edward.L. ordan, Director
 
Division of Emergency Preparedness
 
andlEngineering Response
 
Office'of Inspection and Enforcement


===Technical Contact:===
===Technical Contact:===
Vincent D. Thomas, IE(301) 492-4755


===Attachment:===
===Vincent D. Thomas, IE===
List of Recently Issued IE Information Notices
                    (301) 492-4755 Attachment: List of Recently Issued IE Information Notices
 
\I-/
                                                          Attachment 1 IN 85-42, Rev. 1 August 14, 1985 LIST OF RECENTLY ISSUED
 
IE INFORMATION NOTICES
 
Information                                  Date of
 
Notice No.    Subject                        Issue        Issued to
 
85-42          Loose Phosphor In Panasonic    8/12/85      Materials and fuel
 
Rev. 1        800 Series Badge Thermo-                    cycle licensees
 
luminescent Dosimeter (TLD)
              Elements
 
85-67          Valve-Shaft-To-Actuator Key    8/8/85      All power reactor
 
May Fall Out Of Place When                  facilities holding
 
Mounted Below Horizontal Axis              an OL or CP
 
85-66          Discrepancies Between          8/7/85      All power reactor
 
As-Built Construction                      facilities holding
 
Drawings And Equipment                      an OL or CP
 
Installations
 
85-65          Crack Growth In Steam          7/31/85      All PWR facilities
 
Generator Girth Welds                      holding an OL or CP
 
85-64          BBC Brown Boveri Low-Voltage 7/26/85        All power reactor
 
K-Line Circuit Breakers, With              facilities holding
 
Deficient Overcurrent Trip                  an OL or CP
 
Devices Models OD-4 and 5
85-63          Potential for Common-Mode      7/25/85      All power reactor
 
Failure of Standby Gas Treat-              facilities holding
 
ment System on Loss of Off-                an OL or CP
 
Site Power
 
85-62          Backup Telephone Numbers to    7/23/85      All power reactor
 
the NRC Operations Center                  facilities holding
 
an OL and certain
 
fuel facilities
 
85-61          Misadministrations to Patients 7/22/85      All power reactor
 
Undergoing Thyroid Scans                    facilities holding
 
an OL and certain
 
fuel facilities
 
85-60          Defective Negative Pressure    7/17/85      All power reactor
 
Air-Purifying, Fuel Facepiece              facilities holding
 
Respirators                                an OL or CP
 
OL = Operating License


\I-/Attachment 1IN 85-42, Rev. 1August 14, 1985LIST OF RECENTLY ISSUEDIE INFORMATION NOTICESInformation Date ofNotice No. Subject Issue Issued to85-42Rev. 185-6785-66Loose Phosphor In Panasonic 8/12/85800 Series Badge Thermo-luminescent Dosimeter (TLD)Elements85-6585-64Valve-Shaft-To-Actuator KeyMay Fall Out Of Place WhenMounted Below Horizontal AxisDiscrepancies BetweenAs-Built ConstructionDrawings And EquipmentInstallationsCrack Growth In SteamGenerator Girth WeldsBBC Brown Boveri Low-VoltageK-Line Circuit Breakers, WithDeficient Overcurrent TripDevices Models OD-4 and 5Potential for Common-ModeFailure of Standby Gas Treat-ment System on Loss of Off-Site PowerBackup Telephone Numbers tothe NRC Operations Center8/8/858/7/857/31/857/26/857/25/857/23/85Materials and fuelcycle licenseesAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll PWR facilitiesholding an OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL or CPAll power reactorfacilities holdingan OL and certainfuel facilitiesAll power reactorfacilities holdingan OL and certainfuel facilitiesAll power reactorfacilities holdingan OL or CP85-6385-6285-61Misadministrations to Patients 7/22/85Undergoing Thyroid ScansDefective Negative Pressure 7/17/85Air-Purifying, Fuel FacepieceRespirators85-60OL = Operating LicenseCP = Construction Permit}}
CP = Construction Permit}}


{{Information notice-Nav}}
{{Information notice-Nav}}

Latest revision as of 03:39, 24 November 2019

Diesel Generator Failure at Calvert Cliffs Nuclear Station Unit 1
ML031180218
Person / Time
Site: Beaver Valley, Millstone, Hatch, Monticello, Calvert Cliffs, Dresden, Davis Besse, Peach Bottom, Browns Ferry, Salem, Oconee, Mcguire, Nine Mile Point, Palisades, Palo Verde, Perry, Indian Point, Fermi, Kewaunee, Catawba, Harris, Wolf Creek, Saint Lucie, Point Beach, Oyster Creek, Watts Bar, Hope Creek, Grand Gulf, Cooper, Sequoyah, Byron, Pilgrim, Arkansas Nuclear, Three Mile Island, Braidwood, Susquehanna, Summer, Prairie Island, Columbia, Seabrook, Brunswick, Surry, Limerick, North Anna, Turkey Point, River Bend, Vermont Yankee, Crystal River, Haddam Neck, Ginna, Diablo Canyon, Callaway, Vogtle, Waterford, Duane Arnold, Farley, Robinson, Clinton, South Texas, San Onofre, Cook, Comanche Peak, Yankee Rowe, Maine Yankee, Quad Cities, Humboldt Bay, La Crosse, Big Rock Point, Rancho Seco, Zion, Midland, Bellefonte, Fort Calhoun, FitzPatrick, McGuire, LaSalle, 05000000, Zimmer, Fort Saint Vrain, Shoreham, Satsop, Trojan, Atlantic Nuclear Power Plant, Skagit, Marble Hill
Issue date: 08/14/1985
From: Jordan E
NRC/IE
To:
References
IN-85-068, NUDOCS 8508120603
Download: ML031180218 (4)
v • d • e


SSINS No.: 6835 IN 85-68 UNITED STATES

NUCLEAR REGULATORY COMMISSION

OFFICE OF INSPECTION AND ENFORCEMENT

WASHINGTON, D.C. 20555 August 14, 1985 IE INFORMATION NOTICE NO. 85-68: DIESEL GENERATOR FAILURE AT CALVERT

CLIFFS NUCLEAR STATION UNIT 1

Addressees

All nuclear power reactor facilities holding an operating license (OL) or a

construction permit (CP).

Purpose

This information notice is provided to alert licensees of a potentially signif- icant safety problem involving cracked interpolar connecting bars that connect

the damper circuit of each rotor pole to the damper circuit of the adjacent

rotor pole of the emergency diesel generator.

It is suggested that recipients review this information for applicability to

their facilities and consider actions, if appropriate, to preclude similar

problems at their facilities. However, suggestions contained in this informa- tion notice do not constitute NRC requirements; therefore, no specific action

or written response is required.

Description of Circumstances

On May 14, 1985, Calvert Cliffs Unit 1 was shut down for refueling. An overspeed

test on the No. 11 emergency diesel generator (EDG) was initiated with the

generator not connected to its essential bus. During the test, plant personnel

who were stationed in the proximity of the EDG* heard loud, metallic rapping

sounds coming from the generator section of the EDG and immediately terminated

the overspeed test. Examination of the generator revealed that insulation on

the stator windings had been rubbed and abraded to the point where one stator

winding had been exposed. Further examination determined the cause of the

failure to be a broken interpolar connecting bar on the rotor. The bar initially

had broken free on one end and damaged the stator windings. Because the

generator was not connected to its essential bus, electrical field

  • Calvert Cliffs is a 2-unit PWR station with three EDGs that are designated as

follows: Unit 1 (EDG 11), Unit 2 (EDG 21), and shared (EDG 12).

8508120603

IN 85-68 August 14, 1985 excitation had not been applied and no electric arcing

occurred when the stator

windings were damaged. The damaged generator was replaced

with a spare genera- tor and a detailed investigation was undertaken involving

the vendor, Louis

Allis, and the licensee.

A metallurgical analysis on the failed interpolar connecting

predominant cause of failure to be high stresses resulting bar determined the

from periodic

centrifugal loading. To a lesser degree, bending of

the connecting bar, during

initial installation, and thermal expansion also were

considered to be contrib- uting factors in the failure. The licensee reports that

the analysis indicated

the problem was of a design nature and not the result

of a material defect.

Radiographic testing on the damaged generator showed

several cracks in the

remaining interconnecting bars.

The investigation into the generator design determined

that the interpolar

connections between rotor poles are not necessary (a)

if the EDGs are not

operated in parallel, which could cause power pulsations

between units, and (b)

if the plant is operating with a balanced three-phase

electrical load. Calvert

Cliffs does not operate its EDGs in parallel with each

other. Analysis shows

that the potential three-phase electrical load unbalance

factor (i.e.,

single-phase load) does not exceed 10% of the emergency

three-phase load;

therefore, it is not considered a concern. Consequently, the licensee initiated

a program to remove the interpolar connecting bars from

the three EDGs in

service at Calvert-Cl-iffs Units 1 and 2.

On the basis of these findings, the licensee removed

EDG No. 21 from Unit 2 service on May 26, 1985 to determine if the interpolar

connections on that EDG

were degraded in a similar manner. Test results indicated

cracks were evident.

On this basis, the EDG No. 12 (which applies emergency

power to either Units 1 or 2) was declared inoperable. Under this set of conditions, Calvert Cliffs

Unit 2, which was operating at 100% full power, started

shutting down. In

order to continue power operation of Unit 2, the replacement

EDG from Unit 1 was connected and aligned to Unit 2 to provide the necessary

emergency power

source and the shutdown was terminated.

The licensee's corrective action, to terminate the limiting

condition for

operation, discussed above, involved the immediate removal

of the interpolar

connections from EDGs 12 and 21. Postmodification qualification

conducted on both EDGs, proved to be satisfactory. testing, The licensee's longer term corrective action plans are

to remove the interpolar

connections from the replacement (spare) EDG.

Discussion:

Typically, a diesel generator that employs the continuous

damper circuit design

(i.e., using interpolar connecting bars) uses 16 connecting

bars. These bars

are installed so that each of the eight rotor poles

on the generator has two

connecting bars, one installed on the front and one

on the back of each rotor

pole. Noncontinuous damper circuit design does not

employ interpolar connec- tions between the damper circuits on the rotor poles.

IN 85-68 August 14, 1985 The safety concern of this event is the common cause failure mechanism if

similar cracked connecting bars exist on all diesel generators at a nuclear

power plant (as was the case at Calvert Cliffs). Cracked connecting bars can

lead to a condition that adversely affects the operating voltages which are

necessary to operate essential equipment during accident conditions.

Because of the generic implications of the Calvert Cliffs event, the vendor, Louis Allis, issued a 10 CFR 21 report on the potential problem to the NRC on

May 21, 1985. A followup letter, dated May 29, 1985, from Louis Allis to the

NRC, briefly discussed the problem and identified other facilities that use

similar Louis Allis generator units. Colt Industries also forwarded a Louis

Allis report dated June 3, 1985, that identified the major cause for interpolar

connecting bars cracking and provided a basis for requesting removal of the

interconnecting bars from similarly designed generators in service at other

facilities. The June 3, 1985 report from Louis Allis to Colt Industries also

was sent to end-users of the Louis Allis generator units.

As a result of the early notifications discussed above, the licensees of TMI/1, Vermont Yankee, and Peach Bottom Units 2 and 3 all report that they have either

removed the interpolar connections or have established plans to have them

removed from the affected generator units in service at their facilities.

Although no similar interpolar connecting bar failures have been reported, related to other generator units, generators supplied by manufacturers other

than Louis Allis may have similar design features.

Additionally, licensees are reminded that if corrective actions are taken to

resolve observed degradation of interpolar connecting bars this action should

be reported to the NRC using the existing reporting requirements specified in

10 CFR 50.72 and 10 CFR 50.73.

No specific action or written response is required by this notice. If you have

any questions about this matter, please contact the Regional Administrator of

the appropriate Regional Office or this office.

A/

.Edward.L. ordan, Director

Division of Emergency Preparedness

andlEngineering Response

Office'of Inspection and Enforcement

Technical Contact:

Vincent D. Thomas, IE

(301) 492-4755 Attachment: List of Recently Issued IE Information Notices

\I-/

Attachment 1 IN 85-42, Rev. 1 August 14, 1985 LIST OF RECENTLY ISSUED

IE INFORMATION NOTICES

Information Date of

Notice No. Subject Issue Issued to

85-42 Loose Phosphor In Panasonic 8/12/85 Materials and fuel

Rev. 1 800 Series Badge Thermo- cycle licensees

luminescent Dosimeter (TLD)

Elements

85-67 Valve-Shaft-To-Actuator Key 8/8/85 All power reactor

May Fall Out Of Place When facilities holding

Mounted Below Horizontal Axis an OL or CP

85-66 Discrepancies Between 8/7/85 All power reactor

As-Built Construction facilities holding

Drawings And Equipment an OL or CP

Installations

85-65 Crack Growth In Steam 7/31/85 All PWR facilities

Generator Girth Welds holding an OL or CP

85-64 BBC Brown Boveri Low-Voltage 7/26/85 All power reactor

K-Line Circuit Breakers, With facilities holding

Deficient Overcurrent Trip an OL or CP

Devices Models OD-4 and 5

85-63 Potential for Common-Mode 7/25/85 All power reactor

Failure of Standby Gas Treat- facilities holding

ment System on Loss of Off- an OL or CP

Site Power

85-62 Backup Telephone Numbers to 7/23/85 All power reactor

the NRC Operations Center facilities holding

an OL and certain

fuel facilities

85-61 Misadministrations to Patients 7/22/85 All power reactor

Undergoing Thyroid Scans facilities holding

an OL and certain

fuel facilities

85-60 Defective Negative Pressure 7/17/85 All power reactor

Air-Purifying, Fuel Facepiece facilities holding

Respirators an OL or CP

OL = Operating License

CP = Construction Permit


Retrieved from "https://kanterella.com/w/index.php?title=Information_Notice_1985-68,_Diesel_Generator_Failure_at_Calvert_Cliffs_Nuclear_Station_Unit_1&oldid=2200558"