Protecting People and the EnvironmentUNITED STATES NUCLEAR REGULATORY COMMISSION
ACCESSION #: 9707170088
ATTACHMENT (1)
10 CFR PART 21 REPORT CONCERNING FAILURE OF
MAIN STEAM HEADER RADIATION MONITORS
SUPPLIED BY NUCLEAR RESEARCH CORPORATION
Calvert Cliffs Nuclear Power Plant, Units 1 and 2
Docket Nos: 50-317 and 50-318
(i) Name and Address of Individual Making Notification:
C. H. Cruse, Vice-President, Nuclear Energy Division
Baltimore Gas and Electric Company
Calvert Cliffs Nuclear Power Plant
1650 Calvert Cliffs Parkway
Lusby, MD 20657
(ii) Basic Component Affected.
Nuclear Research Corporation Extended Range Gamma Scintillation
Detector MD-55E(V3)
(iii) Firm Supplying Component:
Nuclear Research Corporation
125 Titus Avenue
Warrington, PA 18976
(iv) Nature of the Defect
The Main Steam Reader Radiation Monitor detectors are located
in the Main Steam Isolation Valve (MSIV) room. The detectors
are mounted adjacent to their respective main steam line, close
to the containment penetration, upstream of the Main Steam
Safety Valves (MSSVs). The Main Steam Header Radiation
Monitors arc designed to measure potential noble gas releases
to the environment in the event of primary-to-secondary steam
generator tube leakage concurrent with lifting of the MSSVs,
atmospheric dump valves or the exhaust from the turbine-driven
auxiliary feedwater pumps. The purpose of the Main Steam
Header Radiation Monitors is to
ATTACHMENT (1)
10 CFR PART 21 REPORT CONCERNING FAILURE OF
MAIN STEAM HEADER RADIATION MONITORS
SUPPLIED BY NUCLEAR RESEARCH CORPORATION
detect significant radiological releases and Provide meaningful
release information for offsite emergency actions.
If a Main Steam Header Radiation Monitor is inoperable, then in
accordance with Technical Specification 3.3.3.1, Action
Statement (30) and the Emergency Response Plan Implementation
Procedures, the preplanned alternate method of monitoring
effluent noble gas in the respective main steam header is
implemented.
The Unit Nos. 1 and 2 safety-related Main Steam Header
Radiation Monitors were recently replaced in accordance with
approved modifications. The Unit 1 radiation monitors were
tested and declared OPERABLE in early May 1997. The Unit 2
radiation monitors were tested and declared OPERABLE in late
May 1997. In early June 1997, the Unit 1 Main Steam Header
Radiation Monitors successfully passed their first monthly
channel functional surveillance tests required by Technical
Specification 3.3.3.1. On June 6, 1997, during performance of
their first monthly channel functional test, Unit 2 Main Steam
Header Radiation Monitors Nos. 21 and 22 failed to respond
during a checksource test, were declared not OPERABLE, and the
alternate preplanned monitoring method was implemented. On
June 10, 1997, following evaluation of troubleshooting results
on the Unit 2 Main Steam Header Radiation Monitor detectors,
confirmatory tests performed on the Unit 1 Nos. 11 and 12 Main
Steam Header Radiation Monitors revealed that they also failed
to respond during a checksource test. These Unit 1 radiation
monitors were removed from OPERABLE status, and the alternate
preplanned monitoring method was implemented.
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ATTACHMENT (1)
10 CFR PART 21 REPORT CONCERNING FAILURE OF
MAIN STEAM HEADER RADIATION MONITORS
SUPPLIED BY NUCLEAR RESEARCH CORPORATION
Although the inoperability of Nos. 11 and 12 (Nos. 21 and 22)
Main Steam Header Radiation Monitors has not affected Unit 1
(Unit 2) operation, the detectors failed to operate as exported
over the required temperature range. This defect resulted in
the inability of these safety-related components to perform
their intended function (i.e., detect significant radiological
releases and provide meaningful release information for offsite
emergency actions). The Main Stem Header Radiation Monitors
are passive monitoring instrumentation that do not interface
with any other safety-related equipment. However, these
radiation monitors are designated safety-related and are
designed to be operational during and following the event The
details of the discovery and nature of the defect are provided
below.
Numbers 21 and 22 Main Steam Header Radiation Monitors were
replaced per an approved modification during the Unit 2 spring
1997 refueling outage. Following the installation, Engineering
Test Procedures were performed which included the performance
of checksource tests. The monitors satisfactorily passed all
requirements of the Engineering Test Procedures (perforated
with Unit 2 in MODE 5 and a MSIV room ambient temperature of
approximately 90 Degrees F) and were placed in an OPERABLE
status in late-May 1997.
On June 6, 1997, during the performance of the first monthly
channel functional test required by Unit 2 Technical
Specifications surveillance requirements, Nos. 21 and 22 Main
Steam Header Radiation Monitors failed to respond during the
checksource test. The radiation monitor was removed from
OPERABLE status and the alternate preplanned monitoring method
was implemented. Troubleshooting on No. 21 Main Steam Header
Radiation Monitor determined that the checksource was properly
aligned with respect to the collimating hole during the
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ATTACHMENT (1)
10 CFR PART 21 REPORT CONCERNING FAILURE OF
MAIN STEAM HEADER RADIATION MONITORS
SUPPLIED BY NUCLEAR RESEARCH CORPORATION
checksource test. However, no response from the detector was
noted during subsequent checksource tests. Further
troubleshooting found that no response was seen when the
checksource was placed directly on the detector. Satisfactory
source strength of the checksource was confirmed by placing it
directly on a personnel contamination gamma detector. Several
checksource tests were then performed on No. 22 Main Steam
Header Radiation Monitor and no detector response was noted.
During evaluation of the troubleshooting results above, it was
suspected that a generic problem may exist with detector
performance. Therefore, on June 10, 1997, confirmatory
checksource tests were performed on the similar Unit 1 Nos. 11
and 12 Main Steam Header Radiation Monitors. Both Unit 1
radiation monitors failed to respond to a checksource test,
were removed from OPERABLE status, and the alternate preplanned
monitoring method was implemented. (Note: !he Unit 1 Main
Steam Header Radiation Monitors were replaced earlier in 1997
per an approved modification. These new Unit 1 radiation
monitors were tested satisfactorily (with Unit 1 operating in
MODE 1 and MSIV room ambient temperature approximately 110
Degrees F - 120 Degrees F), in accordance with similar
Engineering Test Procedures as those performed on the Unit 2
Main Steam Header Radiation Monitors. The Unit 1 Nos. 11 and
12 Main Steam Header Radiation Monitors were placed in an
OPERABLE status in early-May 1997. These Unit 1 radiation
monitors satisfactorily completed their first monthly channel
functional test required by Technical Specification
surveillance, requirements earlier in June 1997. The MSIV room
ambient temperature was still approximately 110 Degrees F -120
Degrees F.]
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ATTACHMENT (1)
10 CFR PART 21 REPORT CONCERNING FAILURE OF
MAIN STEAM HEADER RADIATION MONITORS
SUPPLIED BY NUCLEAR RESEARCH CORPORATION
Following confirmation that a generic detector performance
problem existed, additional troubleshooting (using No. 21 Main
Steam Header Radiation Monitor) determined that the detectors
were sensitive to elevated temperatures. With MSIV room
ambient temperature measured at approximately 135 Degrees F, a
contact temperature reading on No. 21 Main Steam Header
Radiation Monitor detector measured approximately 155 Degrees
F. This detector was removed from the Unit 2 MSIV room,
allowed to cool to approximately 80 Degrees F, and was returned
to the MSIV room. A checksource test was immediately performed
with satisfactory results. However, subsequent checksource
tests, performed at approximately 3 to 5 minute intervals,
showed a degrading detector performance.
Checks utilizing secondary calibration button check sources
were performed on No. 21 Main Steam Header Radiation Monitor
detector after cooling the detector to approximately 80 Degrees
F, with the detector at a MSIV room ambient temperature of 135
Degrees F, and with the detector at approximately 155 Degrees
F. Degraded detector performance was noted at the elevated
temperatures.
Vendor documentation states that this detector should be
capable of operating satisfactorily over a temperature range of
-22 Degrees F to +194 Degrees F. Vendor environmental test
data appeared to substantiate the published detector operating
temperature range. However, based upon the results of the
troubleshooting and the vendor specifications, it was concluded
that the detectors were not operating as expected over the
required temperature range. The cause of the inoperability of
the Main Steam Header Radiation Monitors was determined to be
inadequate vendor design of the detector temperature
compensation circuit. Baltimore Gas and Electric Company (BGE)
design specification for the new safety-related Main Steam
Header Effluent
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ATTACHMENT (1)
10 CFR PART 21 REPORT CONCERNING FAILURE OF
MAIN STEAM HEADER RADIATION MONITORS
SUPPLIED BY NUCLEAR RESEARCH CORPORATION
Monitors requires that these detectors be able to operate at a
continuous temperature of 170 Degrees F. In addition, the
design specifications state that these radiation monitors shall
meet the requirements of Regulatory Guide 1.97, Table 3,
Category 2, Type E Variable, "Vent From Steam Generator Safety
Relief Valves or Atmospheric Dump Valves," in which a Type E
Variable is defined as those variables to be monitored as
required for use in determining the magnitude of the release of
radioactive materials and continually assessing such releases.
The design specifications define the safety classification of
the Main Steam Header Radiation Monitors stating, in part, that
all safety-related equipment must be manufactured and procured
under a 10 CFR Part 50, Appendix B program and that the
requirements of 10 CFR Part 21 apply.
(v) Date on Which Defect Was Identified:
On June 6, 1997, Issue Reports were written documenting that
Nos. 21 and 22 Main Steam Header Radiation Monitors had failed
their checksource tests during surveillance testing and were
declared not OPERABLE. On June 10, 1997, an Issue Report was
written documenting that the Unit 1 Main Steam Header Radiation
Monitors had failed the requested checksource tests (and
declared not OPERABLE) that were performed due to the generic
concern with all the Main Steam Header Radiation Monitors. On
July 1, 1997, we submitted a Special Report to the Nuclear
Regulatory Commission concerning the inoperability of the Unit
1 and Unit 2 Main Steam Header Radiation Monitors discussed
above. The extent of the deviation (i.e., departure from the
design specification that the detectors be able to operate at a
continuous temperature of 170 Degrees F) that resulted in the
failed surveillance testing and inoperability of the Main Steam
Header
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ATTACHMENT (1)
10 CFR PART 21 REPORT CONCERNING FAILURE OF
MAIN STEAM HEADER RADIATION MONITORS
SUPPLIED BY NUCLEAR RESEARCH CORPORATION
Radiation Monitors, identified the inability of these safety-
related components to provide meaningful radiological release
information as designed.
(vi) Number and Location of Components:
There are two Nuclear Research Corporation Extended Range Gamma
Scintillation Detectors [MD-55E(V3)], one for each main steam
line, located in the MSIV room for each unit.
(vii) Corrective Actions:
We have communicated the detector performance problem to the
vendor. The detectors and associated pre-amplifiers were
returned to the vendor for confirmatory testing and
modification, if necessary. The vendor confirmed that the
detectors were not operating as expected over the required
temperature range and that the originally supplied
environmental test data was incomplete. A proposed
modification to the detector temperature compensation circuit
has been temporarily implemented and is undergoing initial
vendor testing.
Baltimore Gas and Electric Company has prescribed additional
testing to be performed by the vendor on the proposed
modification. Following the completion of this testing and BGE
acceptance of the results, formal factory acceptance testing of
the modified detectors will occur. Upon satisfactory
completion of the factory acceptance testing, BGE acceptance
testing per approved Engineering Test Procedures will be
performed. We plan to conduct this acceptance testing at
Calvert Cliffs with the units operating and the MSIV rooms at
elevated temperatures (similar conditions to when the problem
with the detector response was first identified). Following
successful completion of the site acceptance tests, the Unit 1
and Unit 2 Main Steam
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ATTACHMENT (1)
10 CFR PART 21 REPORT CONCERNING FAILURE OF
MAIN STEAM HEADER RADIATION MONITORS
SUPPLIED BY NUCLEAR RESEARCH CORPORATION
Header Radiation Monitors will be returned to OPERABLE status.
The estimated completion date for the return of all Main Steam
Header Radiation Monitors to OPERABLE status is August 31,
1997.
An INPO Nuclear NETWORK message will be issued to make other
industry personnel aware of this problem.
(viii) Other Advice Related to Purchasers or Licensing:
None.
8
POWER REACTOR EVENT NUMBER: 32621
FACILITY: CALVERT CLIFFS REGION: 1 NOTIFICATION DATE: 07/14/97
UNIT: [1] [2] [ ] STATE: MD NOTIFICATION TIME: 14:11 [ET]
RX TYPE: [1] CE, [2] CE EVENT DATE: 06/06/97
EVENT TIME: 00:00[EDT]
NRC NOTIFIED BY: PETER KATZ LAST UPDATE DATE: 07/14/97
HQ OPS OFFICER: STEVE SANDIN
NOTIFICATIONS
EMERGENCY CLASS: NOT APPLICABLE
10 CFR SECTION: HERB WILLIAMS RDO
CCCC 21.21 UNSPECIFIED PARAGRAPH
VERN HODGE (VIA FAX) NRR
UNIT SCRAM CODE RX CRIT INIT PWR INIT RX MODE CURR PWR CURR RX
MODE
1 N Y 100 POWER OPERATION 100 POWER OPERATION
2 N Y 99 POWER OPERATION 99 POWER OPERATION
EVENT TEXT
THE LICENSEE IS MAKING A 10 CFR PART 21 NOTIFICATION.
THE LICENSEE IDENTIFIED THAT THE RECENTLY INSTALLED MAIN STEAM
HEADER
RADIATION MONITORS, EXTENDED GAMMA SCINTILLATION DETECTORS
SUPPLIED BY
NUCLEAR RESEARCH CORPORATION, MODEL #MD-55E(V3), FAILED A CHECK
SOURCE
VERIFICATION UNDER NORMAL OPERATING CONDITIONS WITH AMBIENT
TEMPERATURES
BETWEEN 110 AND 120 Degrees F. THE DESIGN SPECIFICATION REQUIRES
OPERATION UP TO 170 Degrees F WHICH WAS WITHIN THE VENDOR SUPPLIED
OPERATING RANGE OF -22 TO 194 Degrees F. THE PROBLEM APPEARS TO BE
RELATED TO THE TEMPERATURE COMPENSATION. THE DETECTORS WERE
DECLARED
INOPERABLE AND REMOVED FOR REPAIR AT THE VENDOR'S FACILITY. THIS
PLACES
BOTH UNITS IN TECHNICAL SPECIFICATION 3.3.3.1, ACTION STATEMENT (30), AND
IN THE EMERGENCY RESPONSE PLAN IMPLEMENTATION PROCEDURES WHICH
ALLOWS AN
ALTERNATE METHOD OF MONITORING EFFLUENT NOBLE GAS IN THE
RESPECTIVE MAIN
STEAM HEADER.
THE LICENSEE PLANS TO INFORM THE NRC RESIDENT INSPECTOR.
*** END OF DOCUMENT ***
