Information Notice No. 86-42: Improper Maintenance of Radiation Monitoring Systems
SSINS No: 6835
IN 86-42
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, DC 20555
June 9, 1986
Information Notice No. NO 86-42: IMPROPER MAINTENANCE OF RADIATION
MONITORING SYSTEMS
Addressees:
All nuclear power reactor facilities holding an operating license (OL) or a
construction permit (CP)
Purpose and Summary:
This notice is issued to alert licensees to the potential for defeating the
safety function associated with radiation monitoring systems by not properly
adhering to established surveillance and maintenance procedures A recent
event at a BWR, when an electrical jumper was inadvertently left in place
after a planned surveillance, led to failure to maintain secondary
containment integrity during irradiated fuel movement
It is expected that recipients will review the information for applicability
to their maintenance and surveillance program and consider actions, if
appropriate, to preclude similar problems at their facility However,
suggestions contained in this notice do not constitute NRC requirements;
therefore, no specific action or written response is required
Previous Related Correspondence
Information Notice No. No 83-23, "Inoperable Containment Atmosphere Sensing
Systems," April 25, 1983
INPO Significant Event Report, 35-83, "Compromise of Secondary Containment
Integrity," June 9, 1983
Information Notice No. No 83-52, "Radioactive Waste Gas System Events,"
August 9, 1983
Information Notice No. No 84-37, "Use of Lifted Leads and Jumpers During
Maintenance or Surveillance Testing," May 10, 1984
Description of Circumstances:
On November 18, 1985 the Cooper Nuclear Station was in a shutdown condition
(reactor coolant temperature less than 212 F and vented) with acceptance
testing for a plant design change in progress When this testing failed to
provide for the required Group VI isolation (various containment isolation
and
8606040007
IN 86-42
June 9, 1986
Page 2 of 3
engineered safety feature (ESF) initiations), the licensee investigated and
discovered that electrical jumpers were installed in the reactor building
(RB) ventilation radiation monitors (VRM) auxiliary trip units These
jumpers prohibited a Group VI isolation by a high radiation signal from the
RB VRM The jumpers were immediately removed and the NRC was promptly
notified as required by 10 CFR 5072
The licensee's subsequent investigation revealed that the electrical jumpers
had been installed on November 13, 1985 by an instrument and control
technician during a routine surveillance procedure to functionally test the
VRM These jumpers are used to prevent trip and equipment operations during
the required functional/calibration testing The technician had signed off
the procedural step requiring jumper removal (before actually removing the
electrical jumper) and then started checking control room annunciator and
trip signal status The technician then became involved in other unrelated
craft work and forgot to go back and remove the jumpers
On November 18, 1986, before discovery of the jumpers, 18 irradiated fuel
bundles were loaded into a spent fuel shipping cask Failure to properly
implement the surveillance procedure for operability checks of radiation
monitors rendered inoperable the automatic initiation of the standby gas
treatment system (SBGTS) and automatic isolation of the reactor building
upon receipt of a high radiation signal This degraded condition lasted
approximately 5 days However, control room annunciators and instrumentation
that would provide warning to operators of any high radiation problems
remained operational during the 5 days Manual-start of the SBGTS and
reactor building isolation capabilities from the control room remained
available during the event
Discussion:
This event clearly demonstrates that the level of attention given to the
procedural controls for the maintenance of radioactive monitoring systems
providing ESF actuation can be significantly improved While there were no
actual radiological consequences of this event, the NRC took escalated
enforcement actions (issued civil penalty) to emphasize the importance of
correctly performing surveillance procedures on systems designed to mitigate
or prevent accidents Attachment No 1 contains 6 summaries of related
events taken from the Licensee Event Report files Further examples of how
improper maintenance practices have degraded radiation monitoring systems
are provided in the listed Previous Related Correspondence section
The Cooper Station initiated the following corrective actions to prevent
recurrence:
1 All temporary modifications (eg, electrical jumpering, fuse removal)
performed by the involved technician since October 5, 1985 were
independently verified
2 Site management stressed the importance of procedural adherence--sign
off the procedural step after completing the required action
IN 86-42
June 9, 1986
Page 3 of 3
3 All surveillance procedures requiring temporary modifications to system
or plant components were reviewed for deficiencies, and these
procedures will be modified to provide for independent verification to
ensure that temporary modifications are removed and the
system/component is fully restored to operational status
No specific action or written response is required by this information
notice If you have any questions about this matter, please contact the
Regional Administrator of the appropriate regional office or this office
Edward L Jordan, Director
Division of Emergency Preparedness
and Engineering Response
Office of Inspection and Enforcement
Technical Contacts: James E Wigginton, IE
(301) 492-4967
Roger L Pedersen, IE
(301) 492-9425
Attachments:
1 Event Summaries
2 List of Recently Issued IE Information Notices
Attachment 1
IN 86-42
June 9, 1986
Page 1 of 2
EVENT SUMMARIES
Unplanned Gaseous Release (Connecticut Yankee, PWR)
LER 85-025
Event Date: 9/19/85
Cause: Personnel Maintenance Error
Abstract: With the plant operating at 100 percent power, a main stack high
radiation alarm was received during routine scheduled maintenance
on a pressure actuated valve in the gaseous waste stream The
unplanned release occurred through an isolation valve
inadvertently left open, allowing the on-line waste gas decay tank
a release path The maintenance tag-out procedure correctly
required the isolation valve to be isolated, but the operator shut
the wrong valve The total noble gas release was approximately 20
curies (about 14 percent of technical specification limit)
Licensee corrective action included clearly relabeling associated
valves and discussion of the event with operation staff
Containment Radiation Monitor Isolated (Byron 1, PWR)
LER 85-026
Event Date: 2/28/85
Cause: Improper Valve Position
Abstract: With the reactor at zero percent power, a containment radiation
monitor used for required reactor coolant leakage detection was
inadvertently left isolated for 72 hours from containment after
maintenance on an associated valve Abnormal in-leakage at the
monitor caused normal-range readings on RM-11 console in the main
control room (leakage was later repaired) Licensee corrective
action included implementing administrative controls to ensure
system integrity/proper restoration after completion of
maintenance activities
Liquid Radwaste Effluent Monitor Isolated (Cooper, BWR)
LER 84-008
Event Date: 6/09/84
Cause: Monitor Discharge Valve Shut
Abstract: A liquid discharge occurred without required continuous radiation
monitoring because the liquid effluent radiation monitor was
isolated No discharge limits were exceeded Two days before the
event, a technician apparently shut the radiation monitor outlet
valve during maintenance without permission or knowledge of
operations personnel As corrective actions, the licensee revised
controlling procedures and informed all plant operators of the
event
Attachment 1
IN 86-42
June 9, 1986
Page 2 of 2
Off-Gas Stack Monitor Inoperable (Cooper, BWR)
LER 84-006
Event Date: 4/18/84
Cause: Personnel Error
Abstract: With the reactor at 70 percent power, the off-gas stack effluent
sampler was found inoperable The sampler was drawing air from
the surrounding off-gas filter building ambient atmosphere instead
of sampling the plant stack effluent The event resulted from a
chemistry technician failing to follow the approved procedure for
changing the inline particulate filter/iodine cartridge (routine
operation) In addition to making appropriate supervisors and all
chemistry technicians aware of the event, the licensee revised and
clarified the governing procedure to prevent recurrence
Liquid Radwaste Auto-Isolation Valve Inoperative (Hatch 1, BWR)
LER 82-093
Event Date: 11/07/82
Cause: Jumper Installed
Abstract: During a liquid radwaste discharge, the licensee discovered that
the radiation monitor auto control (provides isolation signal upon
high radiation) to the discharge isolation valve was inoperable
However, the monitor's alarm function remained operable An
electrical jumper used during corrective maintenance had not been
removed after the work was completed
Containment Atmosphere Radiation Monitors Isolated (FitzPatrick 1, BWR)
LER 81-061 (Rev 1)
Event Date: 8/21/81
Cause: Containment Isolation Valve Isolated
Abstract: The NRC resident inspector discovered that during normal 85
percent power operations the containment isolation valves for the
containment atmosphere gaseous and particulate monitoring system
had been shut for approximately 22 hours With this loss of
monitoring capability, the technical specifications require a
reactor hot shutdown within 12 hours The event occurred because a
surveillance procedure did not direct the operator to re-open the
isolation valves following the surveillance activities As a
corrective action, the licensee corrected the subject procedure
and reviewed all other surveillance procedures for similar
deficiencies
Page Last Reviewed/Updated Tuesday, March 09, 2021