Information Notice No. 89-60: Maintenance of Teletherapy Units
UNITED STATES
NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS
WASHINGTON, D.C. 20555
August 18, 1989
Information Notice No. 89-60: MAINTENANCE OF TELETHERAPY UNITS
Addressees:
All U.S. Nuclear Regulatory Commission (NRC) Medical Teletherapy Licensees.
Purpose:
An information notice provides information to licensees to consider for
application to their activities. While an Information Notice provides
information to improve safety, to improve compliance, or to notify licensees
of problems or violations of other licensees, it does not establish a new
requirement or require a written response to the NRC.
This notice is intended to alert recipients to NRC concerns about proper
maintenance of teletherapy units. It emphasizes the importance of five-year
inspections and services as required by 10 CFR Section 35.647. It is expected
that licensees will review this information for applicability to their
programs, distribute this Notice to those responsible for radiation safety,
and consider actions, if appropriate, to preclude safety problems from
occurring at their facilities.
Description of Circumstances:
During a routine inspection, NRC inspectors found that the licensee's
teletherapy unit was in poor condition and significantly overdue for service
and preventive maintenance, thus raising the question of whether the unit was
safe to operate. A service company had performed a five-year inspection in
August 1988, and found that many parts that the manufacturer considered
critical components had not been replaced according to the recommended
frequency. In fact, many of the critical components were original parts,
dating from when the unit was first placed into service in 1974.
Examples of critical components needing periodic replacement are: the field
light cord reel, source drawer solenoids, air pressure switch, air hoses and
fittings, and treatment timer. If any of these components failed, it could
significantly increase the potential of the source failing to return to the
shielded position. This could lead to unnecessary radiation exposures to both
employees and patients, or an overexposure or medical misadministration. In
fact, the field light cord reel on this unit had failed in 1983, and the
source could not be fully retracted.
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. IN 89-60
August 18, 1989
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Although the service company informed the licensee of the critical need for
service, the licensee had not taken any action to service the unit.
Apparently, the licensee planned to eventually replace the entire unit.
As a result of the safety concerns raised by NRC, the licensee was required to
complete the needed service on an emergency basis. A heavy patient load was
disrupted temporarily, but the disruption could have been worse if the service
had taken a long time.
Discussion:
Title 10 CFR Section 35.647 requires licensees to have their teletherapy units
fully inspected and serviced during teletherapy source replacements, or at
intervals not to exceed five years, whichever comes first. The purpose of the
inspection is to assure safe operation of the units, specifically proper
functioning of the source exposure mechanism.
Licensees should pay close attention to the results of their five-year
inspections, and assure that recommended service is performed promptly.
Failure to maintain teletherapy units in safe operating condition could result
in radiation incidents and/or enforcement action by NRC.
This information notice does not require any written response. If you have
any questions about this matter, please contact the appropriate NRC Regional
Office or this office.
Richard E. Cunningham, Director
Division of Industrial and
Medical Nuclear Safety, NMSS
Technical Contacts: Jack R. Metzger, NMSS
(301) 492-3424
R. J. Caniano, Region III
(312) 790-5721
Attachments:
1. List of Recently Issued NMSS Information Notices
2. List of Recently Issued NRC Information Notices
. Attachment 2
IN 89-60
August 18, 1989
Page 1 of 1
LIST OF RECENTLY ISSUED
NRC INFORMATION NOTICES
______________________________________________________________________________
Information Date of
Notice No._____Subject_______________________Issuance_______Issued to_________
89-59 Suppliers of Potentially 8/16/89 All holders of OLs
Misrepresented Fasteners or CPs for nuclear
power reactors.
89-58 Disablement of Turbine-Driven 8/3/89 All holders of OLs
Auxiliary Feedwater Pump Due or CPs for PWRs.
to Closure of One of the
Parallel Steam Supply Valves
89-57 Unqualified Electrical 7/26/89 All holders of OLs
Splices in Vendor-Supplied or CPs for nuclear
Environmentally Qualified power reactors.
Equipment
89-56 Questionable Certification 7/20/89 All holders of OLs
of Material Supplied to the or CPs for nuclear
Defense Department by Nuclear power reactors.
Suppliers
89-45, Metalclad, Low-Voltage 7/6/89 All holders of OLs
Supp. 1 Power Circuit Breakers or CPs for nuclear
Refurbished With Substandard power reactors.
Parts
89-55 Degradation of Containment 6/30/89 All holders of OLs
Isolation Capability by a or CPs for nuclear
High-Energy Line Break power reactors.
89-54 Potential Overpressurization 6/23/89 All holders of OLs
of the Component Cooling or CPs for nuclear
Water System power reactors.
89-53 Rupture of Extraction 6/13/89 All holders of OLs
Steam Line on High or CPs for nuclear
Pressure Turbine power reactors.
88-46, Licensee Report of 6/8/89 All holders of OLs
Supp. 3 Defective Refurbished or CPs for nuclear
Circuit Breakers power reactors.
89-52 Potential Fire Damper 6/8/89 All holders of OLs
Operational Problems or CPs for nuclear
power reactors.
______________________________________________________________________________
OL = Operating License
CP = Construction Permit
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