Diesel Generator Failure at Calvert Cliffs Nuclear Station Unit 1ML031180218 |
Person / Time |
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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 |
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Issue date: |
08/14/1985 |
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From: |
Jordan E NRC/IE |
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To: |
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References |
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IN-85-068, NUDOCS 8508120603 |
Download: ML031180218 (4) |
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Similar Documents at 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 |
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Category:NRC Information Notice
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Mclaughlin on NRC, Regarding NRC Information Notice 2006-13: Groundwater Contamination 2020-09-03 The following query condition could not be considered due to this wiki's restrictions on query size or depth: <code> [[:Beaver Valley]] OR [[:Millstone]] OR [[:Hatch]] OR [[:Monticello]] OR [[:Calvert Cliffs]] OR [[:Dresden]] OR [[:Davis Besse]] OR [[:Peach Bottom]] OR [[:Browns Ferry]] OR [[:Salem]] OR [[:Oconee]] OR [[:Mcguire]] OR [[:Nine Mile Point]] OR [[:Palisades]] OR [[:Palo Verde]] OR [[:Perry]] OR [[:Indian Point]] OR [[:Fermi]] OR [[:Kewaunee]] OR [[:Catawba]] OR [[:Harris]] OR [[:Wolf Creek]] OR [[:Saint Lucie]] OR [[:Point Beach]] OR [[:Oyster Creek]] OR [[:Watts Bar]] OR [[:Hope Creek]] OR [[:Grand Gulf]] OR [[:Cooper]] OR [[:Sequoyah]] OR [[:Byron]] OR [[:Pilgrim]] OR [[:Arkansas Nuclear]] OR [[:Three Mile Island]] OR [[:Braidwood]] OR [[:Susquehanna]] OR [[:Summer]] OR [[:Prairie Island]] OR [[:Columbia]] OR [[:Seabrook]] OR [[:Brunswick]] OR [[:Surry]] OR [[:Limerick]] OR [[:North Anna]] OR [[:Turkey Point]] OR [[:River Bend]] OR [[:Vermont Yankee]] OR [[:Crystal River]] OR [[:Haddam Neck]] OR [[:Ginna]] OR [[:Diablo Canyon]] OR [[:Callaway]] OR [[:Vogtle]] OR [[:Waterford]] OR [[:Duane Arnold]] OR [[:Farley]] OR [[:Robinson]] OR [[:Clinton]] OR [[:South Texas]] OR [[:San Onofre]] OR [[:Cook]] OR [[:Comanche Peak]] OR [[:Yankee Rowe]] OR [[:Maine Yankee]] OR [[:Quad Cities]] OR [[:Humboldt Bay]] OR [[:La Crosse]] OR [[:Big Rock Point]] OR [[:Rancho Seco]] OR [[:Zion]] OR [[:Midland]] OR [[:Bellefonte]] OR [[:Fort Calhoun]] OR [[:FitzPatrick]] OR [[:McGuire]] OR [[:LaSalle]] OR [[:05000000]] OR [[:Zimmer]] OR [[:Fort Saint Vrain]] OR [[:Shoreham]] OR [[:Satsop]] OR [[:Trojan]] OR [[:Atlantic Nuclear Power Plant]] OR [[:Skagit]] OR [[:Marble Hill]] </code>.
[Table view]The following query condition could not be considered due to this wiki's restrictions on query size or depth: <code> [[:Beaver Valley]] OR [[:Millstone]] OR [[:Hatch]] OR [[:Monticello]] OR [[:Calvert Cliffs]] OR [[:Dresden]] OR [[:Davis Besse]] OR [[:Peach Bottom]] OR [[:Browns Ferry]] OR [[:Salem]] OR [[:Oconee]] OR [[:Mcguire]] OR [[:Nine Mile Point]] OR [[:Palisades]] OR [[:Palo Verde]] OR [[:Perry]] OR [[:Indian Point]] OR [[:Fermi]] OR [[:Kewaunee]] OR [[:Catawba]] OR [[:Harris]] OR [[:Wolf Creek]] OR [[:Saint Lucie]] OR [[:Point Beach]] OR [[:Oyster Creek]] OR [[:Watts Bar]] OR [[:Hope Creek]] OR [[:Grand Gulf]] OR [[:Cooper]] OR [[:Sequoyah]] OR [[:Byron]] OR [[:Pilgrim]] OR [[:Arkansas Nuclear]] OR [[:Three Mile Island]] OR [[:Braidwood]] OR [[:Susquehanna]] OR [[:Summer]] OR [[:Prairie Island]] OR [[:Columbia]] OR [[:Seabrook]] OR [[:Brunswick]] OR [[:Surry]] OR [[:Limerick]] OR [[:North Anna]] OR [[:Turkey Point]] OR [[:River Bend]] OR [[:Vermont Yankee]] OR [[:Crystal River]] OR [[:Haddam Neck]] OR [[:Ginna]] OR [[:Diablo Canyon]] OR [[:Callaway]] OR [[:Vogtle]] OR [[:Waterford]] OR [[:Duane Arnold]] OR [[:Farley]] OR [[:Robinson]] OR [[:Clinton]] OR [[:South Texas]] OR [[:San Onofre]] OR [[:Cook]] OR [[:Comanche Peak]] OR [[:Yankee Rowe]] OR [[:Maine Yankee]] OR [[:Quad Cities]] OR [[:Humboldt Bay]] OR [[:La Crosse]] OR [[:Big Rock Point]] OR [[:Rancho Seco]] OR [[:Zion]] OR [[:Midland]] OR [[:Bellefonte]] OR [[:Fort Calhoun]] OR [[:FitzPatrick]] OR [[:McGuire]] OR [[:LaSalle]] OR [[:05000000]] OR [[:Zimmer]] OR [[:Fort Saint Vrain]] OR [[:Shoreham]] OR [[:Satsop]] OR [[:Trojan]] OR [[:Atlantic Nuclear Power Plant]] OR [[:Skagit]] OR [[:Marble Hill]] </code>. |
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
|
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|
list | - Information Notice 1985-01, Continuous Supervision of Irradiators (10 January 1985)
- Information Notice 1985-02, Improper Installation and Testing of Differential Pressure Transmitters (11 January 1985)
- Information Notice 1985-03, Separation of Primary Reactor Coolant Pump Shaft and Impeller (15 January 1985)
- Information Notice 1985-04, Inadequate Management of Security Response Drills (17 January 1985)
- Information Notice 1985-05, Pipe Whip Restraints (23 January 1985)
- Information Notice 1985-06, Contamination of Breathing Air Systems (23 January 1985)
- Information Notice 1985-07, Contaminated Radiography Source Shipments (29 January 1985)
- Information Notice 1985-08, Industry Experience on Certain Materials Used in Safety-Related Equipment (30 January 1985)
- Information Notice 1985-09, Isolation Transfer Switches and Post-Fire Shutdown Capability (31 January 1985, Topic: Safe Shutdown)
- Information Notice 1985-10, Posttensioned Containment Tendon Anchor Head Failure (6 February 1985)
- Information Notice 1985-11, Licensee Programs for Inspection of Electrical Raceway and Cable Installations (11 February 1985)
- Information Notice 1985-12, Recent Fuel Handling Events (11 February 1985)
- Information Notice 1985-13, Consequences of Using Soluble Dams (21 February 1985, Topic: Hydrostatic)
- Information Notice 1985-14, Failure of a Heavy Control Rod (B4C) Drive Assembly to Insert on a Trip Signal (22 February 1985)
- Information Notice 1985-15, Nonconforming Structural Steel for Safety-Related Use (22 February 1985)
- Information Notice 1985-16, Time/Current Trip Curve Discrepancy of ITE/Siemens-Allis Molded Case Circuit Breaker (27 February 1985)
- Information Notice 1985-17, Possible Sticking of Asco Solenoid Valves (1 March 1985)
- Information Notice 1985-18, Failures of Undervoltage Output Circuit Boards in the Westinghouse-Designed Sold State Protection System (7 March 1985)
- Information Notice 1985-19, Alleged Falsification of Certifications and Alteration of Markings on Piping, Valves, and Fittings (11 March 1985)
- Information Notice 1985-20, Motor-Operated Valve Failures Due to Hampering Effect (12 March 1985)
- Information Notice 1985-21, Main Steam Isolation Valve Closure Logic (18 March 1985)
- Information Notice 1985-22, Failure of Limitorque Motor-Operated Valves Resulting from Incorrect Installation of Pinion Gear (21 March 1985)
- Information Notice 1985-23, Inadequate Surveillance and Postmaintenance and Postmodification System Testing (22 March 1985)
- Information Notice 1985-24, Failures of Protective Coatings in Pipes and Heat Exchangers (26 March 1985, Topic: Ultimate heat sink, Coatings)
- Information Notice 1985-25, Consideration of Thermal Conditions in the Design and Installation of Supports for Diesel Generator Exhaust Silencers (2 April 1985, Topic: Coatings)
- Information Notice 1985-26, Vacuum Relief System for Boiling Water Reactor Mark I and Mark II Containments (2 April 1985, Topic: Coatings)
- Information Notice 1985-27, Notifications to the NRC Operations Center and Reporting Events in Licensee Event Reports (3 April 1985, Topic: Coatings)
- Information Notice 1985-28, Partial Loss of AC Power and Diesel Generator Degradation (9 April 1985, Topic: Coatings)
- Information Notice 1985-30, Microbiologically Induced Corrosion of Containment Service Water System (19 April 1985, Topic: Hydrostatic, Coatings, Biofouling)
- Information Notice 1985-31, Buildup of Enriched Uranium in Ventilation Ducts and Associated Effluent Treatment Systems (19 April 1985, Topic: Coatings)
- Information Notice 1985-32, Recent Engine Failures of Emergency Diesel Generators (22 April 1985, Topic: Coatings)
- Information Notice 1985-33, Undersized Nozzle-To-Shell Welded Joints in Tanks and Heat Exchangers Constructed Under the Rules of the ASME Boiler and Pressure Vessel Code (22 April 1985)
- Information Notice 1985-34, Heat Tracing Contributes to Corrosion Failure of Stainless Steel Piping (30 April 1985, Topic: Hydrostatic)
- Information Notice 1985-35, Failure of Air Check Valves to Seat (30 April 1985)
- Information Notice 1985-35, Failure of Air Check Valves To Seat (30 April 1985)
- Information Notice 1985-37, Chemical Cleaning of Steam Generators at Millstone 2 (14 May 1985)
- Information Notice 1985-38, Loose Parts Obstruct Control Rod Drive Mechanism (21 May 1985)
- Information Notice 1985-39, Auditability of Electrical Equipment Qualification Records at Licensees' Facilities (22 May 1985)
- Information Notice 1985-40, Deficiencies in Equipment Qualification Testing and Certification Process (22 May 1985)
- Information Notice 1985-43, Radiography Events at Power Reactors (30 May 1985, Topic: High Radiation Area, Scaffolding)
- Information Notice 1985-44, Emergency Communication System Monthly Test (30 May 1985, Topic: Health Physics Network)
- Information Notice 1985-46, Clarification of Several Aspects of Removable Radioactive Surface Contamination Limits for Transport Packages (10 June 1985)
- Information Notice 1985-47, Potential Effect of Line-Induced Vibration on Certain Target Rock Solenoid-Operated Valves (18 June 1985)
- Information Notice 1985-48, Respirator Users Notice: Defective Self Contained Breathing Apparatus Air Cylinders (19 June 1985, Topic: Hydrostatic)
- Information Notice 1985-49, Relay Calibration Problem (1 July 1985)
- Information Notice 1985-50, Complete Loss of Main and Auxiliary Feedwater at a PWR Designed by Babcock & Wilcox (8 July 1985)
- Information Notice 1985-51, Inadvertent Loss or Improper Actuation of Safety-Related Equipment (10 July 1985)
- Information Notice 1985-52, Errors in Dose Assessment Computer Codes and Reporting Requirements Under 10 CFR Part 21 (10 July 1985)
- Information Notice 1985-53, Performance of NRC-Licensed Individuals While on Duty (12 July 1985)
- Information Notice 1985-54, Teletherapy Unit Malfunction (15 July 1985)
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