Information Notice 1986-42, Improper Maintenance of Radiation Monitoring Systems
SSINS No.: 6835 IN 86-42
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF INSPECTION AND ENFORCEMENT
WASHINGTON, D.C. 20555
June 9, 1986
IE INFORMATION NOTICE 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
IE Information Notice 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.
IE Information Notice No. 83-52, "Radioactive Waste Gas System Events,"
August 9, 1983.
IE Information Notice 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 2120F 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
Copies to: Withers, Yundt, Lentsch, Orser, Steele, E. Burton, E. Jordan, A. Holm, iLIS;.j. A. Olmstead, S. Hoag, S. Sautter, TNP:GOV REL F:NRC CHRONO,
TNiPGOV REL F:NRC IE Information Notice 86-42 PGE OAR Action - M. H. Halmros (Due 8/12/86)
NSRD Action - M. H. Malmros
IN 86-42 June 9, 1986 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 50.72.
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 approxi- mately 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 enforce- ment 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 (e.g., electrical jumpering, fuse removal)
performed by the involved technician since October 5, 1985 were indepen- dently 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 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 tempo- rary 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.
4'-CJ1ward L. Jord, Director
Division of Edergency 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
June 9, 1986 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 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> from containment after
maintenance on an associated valve. Abnormal in-leakage at the
monitor caused normal-range readings on RM-li 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 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 hours2.546296e-4 days <br />0.00611 hours <br />3.637566e-5 weeks <br />8.371e-6 months <br />. With this loss of monitoring capability, the technical specifications require a reactor hot shutdown within
12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
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.
4'
Attachment 2
June 9, 1986
LIST OF RECENTLY ISSUED
IE INFORMATION NOTICES
Information
Date of
Notice No.
Subject
Issue
Issued to
86-41
86-32 Sup. 1
86-40
86-39
86-38
86-37
86-36
86-35
86-34
Evaluation Of Questionable
Exposure Readings Of Licensee
Personnel Dosimeters
Request For Collection Of
Licensee Radioactivity
Measurements Attributed To
The Chernobyl Nuclear Plant
Accident
Degraded Ability To Isolate
From Low-Pressure Coolant
Systems in BWRS
Failures Of RHR Pump Motors
And Pump Internals
Deficient Operator Actions
Following Dual Function Valve
Failures
Degradation Of Station
Batteries
Change In NRC Practice
Regarding Issuance Of
Confirming Letters To
Principal Contractors
6/9/86
6/6/86
6/5/86
5/20/86
5/20/86
5/16/86
5/16/86
All byproduct
material licensees
All power reactor
facilities holding
All power reactor
facilities holding
All power reactor
facilities holding
All power reactor
facilities holding
All power reactor
facilities holding
All power reactor
facilities holding
All power reactor
facilities holding
All power reactor
facilities holding
Fire In Compressible Material 5/15/86
At Dresden Unit 3
Improper Assembly, Material
5/13/86
Selection, And Test Of Valves
And Their Actuators
OL = Operating License
CP = Construction Permit