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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. 8908140085 . IN 89-60 August 18, 1989 Page 2 of 2 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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