Headquarters Daily Report
AUGUST 05, 1999
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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 AUGUST 5, 1999
Licensee/Facility: Notification:
Part 21 Database MR Number: H-99-0068
Rosemount Date: 08/05/99
Subject: Part 21 - Potential problem with Rosemount pre-1987 trip units
Discussion:
VENDOR: Rosemount PT21 FILE NO: 99-31-0
DATE OF DOCUMENT: 06/18/99 ACCESSION NUMBER:
SOURCE DOCUMENT: EN 35844 REVIEWER: REXB, D. Skeen
NEW ISSUE. On June 18, 1999, the NRC Operations Center received a letter
from Rosemount Nuclear Instruments, Incorporated, concerning a potential
problem with a specific capacitor used in the circuit boards of Model
510DU and 710DU trip units. These trip units are widely used in BWR
plants in various applications to provide inputs to the nuclear steam
supply shutoff system (NSSSS) as well as to provide signals to the
primary containment isolation system.
On October 8, 1987, the BWR Owners Group (BWROG) Scram Frequency
Reduction Maintenance Committee requested information from Rosemount
after a number of BWR utilities experienced failure of the Model 710
analog trip circuit board due to short circuiting of the power input
capacitor (designated as C25 on the circuit board).
On October 20, 1987, Rosemount responded to the BWROG, explaining that
the issue had been identified by its internal returned goods tracking
system. As a result, the vendor performed extensive testing in the spring
of 1987 and determined that the capacitors would only fail when subjected
to environmental parameters (temperature, voltage) outside of normal
operating conditions. However, the vendor acknowledged that a
contaminant, such as moisture introduced into the capacitor could cause
the type of failure described by the customers. In May 1987, the vendor
upgraded the trip card with a more reliable capacitor with enhanced
sealing against contamination. Thus, C25 capacitors with a date code of
8630 or higher are not susceptible to failure due to contamination.
Since 1987, the vendor has identified five more confirmed failures of the
pre-8630 C25 capacitors and 14 cases where the capacitor was replaced by
vendor technicians while repairing trip units, indicating that the
capacitor may have played a role in their failure. The vendor's June 18,
1999 letter alerted its BWR customers that further examination of the
capacitors may be warranted to determine if replacement is necessary.
Rosemount is preparing a procedure to be made available to customers at
no charge for licensees who may wish to rework existing trip units.
NRC staff discussed the issue with Rosemount in a telephone conversation
on June 21, 1999. Rosemount confirmed that the Model 510 and 710 trip
units are only used in BWR applications. The vendor stated that the
4-digit date code on the capacitor is located on one side of the
capacitor at the bottom of a list of other numbers. The vendor
HEADQUARTERS MORNING REPORT PAGE 2 AUGUST 5, 1999
MR Number: H-99-0068 (cont.)
acknowledged that the capacitor may not always be oriented on the circuit
board to enable easy reading. The vendor is working to identify trip
units with the pre-8630 date codes by serial number to make it easier for
customers to identify suspect trip units. Once the units have been
identified by serial number, Rosemount will notify affected customers.
Contact: Dave Skeen, NRR
301-415-1174
E-mail: dls@nrc.gov
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HEADQUARTERS MORNING REPORT PAGE 2 AUGUST 5, 1999
MR Number: H-99-0069
NRR DAILY REPORT ITEM
GENERIC COMMUNICATIONS
Subject: Issuance of Information Notice 99-25
NRC Information Notice 99-25: Year 2000 Contingency Planning Activities
dated August 10, 1999
The U.S. Nuclear Regulatory Commission is issuing this information notice
to inform addressees about contingency planning activities being
undertaken by the NRC in response to potential disruptions of
telecommunications and electrical distribution systems that could occur
during the Year 2000 (Y2K) transition period (December 31, 1999, through
the first few days of 2000).
Technical Contacts: Joseph Giitter, IRO John Jolicoeur, IRO
301-415-7485 301-415-6383
E-mail: jgg@nrc.gov E-mail: jrj1@nrc.gov
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HEADQUARTERS MORNING REPORT PAGE 3 AUGUST 5, 1999
Licensee/Facility: Notification:
Part 21 Database MR Number: H-99-0070
Nuclear Logistics Inc. Date: 08/05/99
Subject: Part 21 - Potential premature overvoltage protection actuation
in dc power supply during diesel generator loading
Discussion:
VENDOR: Nuclear Logistics PT21 FILE NO: 99-30-0
DATE OF DOCUMENT: 06/01/99 ACCESSION NUMBER: 9906070115
SOURCE DOCUMENT: EN 35782 REVIEWER: REXB, D. Skeen
NEW ISSUE. The vendor, Nuclear Logistics Incorporated (NLI) reports a
deviation in a direct current power supply, part number P/N
NLI-LGS-G-24-OV-R-8018, supplied as a Class 1E component. The observed
deviation was a premature overvoltage protection actuation during diesel
generator loading. This condition was determined to be a deviation on
April 19, 1999, but the vendor has not been able to duplicate the
condition in laboratory testing. The affected utility is Public Service
Electric and Gas Company. The vendor notified four other nuclear
customers, including Florida Power and Light, Baltimore Gas and Electric,
Omaha Public Power District, and Virginia Power Company which also have
NLI-L Series power supplies, but NLI has not received any other reports
of power supply problems from those customers.
The vendor plans on witnessing testing of the suspect power supplies in
situ at Public Service Electric and Gas Company later this month to
determine the root cause of the overvoltage protection circuitry
actuation. Information provided to NLI by the licensee indicates that the
power supply, designed to provide 50 amps at 24 V-dc and to provide
protection of the power supply from overvoltage conditions when the
output voltage exceeds 27V-dc, was installed in the emergency diesel
generator control panel along with several control relays which are
required to cycle during diesel generator starting and loading. One
possible theory is that cycling of the relays may cause voltage spikes in
the power supply of sufficient magnitude to actuate the overvoltage
protection circuitry and terminate the power supply output.
The vendor will evaluate the test data, and if it is determined that
there is a design deficiency, other NLI-L Series power supplies will be
tested to ascertain their susceptibility to this problem.
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REGION I MORNING REPORT PAGE 4 AUGUST 5, 1999
Licensee/Facility: Notification:
Connecticut Yankee Atomic Power Co. MR Number: 1-99-0028
Haddam Neck 1 Date: 08/05/99
Hartford,Connecticut Licensee Telecon
Dockets: 50-213
PWR/W-4-LP
Subject: Stand-Down at Haddam Neck to Raise Safety Awareness
Discussion:
On August 4, 1999, Bechtel, the Decommissioning Operations Contractor for
the Haddam Neck facility, issued a Stop Work Order. Within the last
month, many new workers were hired and decommissioning activities were
initiated. The licensee stated that some of these activities were not
conducted consistent with Bechtel's expectations, including a few
recordable OSHA incidents of minor safety significance. As of today
(August 5), Bechtel has conducted an all-hands meeting to review the work
practices and has conducted feedback sessions with its foreman and work
crews. Some limited work activities are expected to resume today.
However, the majority of the work will not resume until the worker
feedback is evaluated, a hazard assessment is conducted by Bechtel to
develop a corrective action plan, a detailed pre-job brief is conducted
with every crew, and a safe work observation program is initiated. Most
work is anticipated to resume next week.
The licensee provided a courtesy notification to the NRC and also plans
to highlight in their daily newsletter the efforts by Bechtel to improve
safety awareness with its new workers. NRC informed the State of
Connecticut.
Regional Action:
NRC will review this matter as part of its routine inspection program
schedule for next week.
Contact: Ronald Bellamy (610)337-5200
Marie Miller (610)337-5205
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