Sealed source and device design safety testing: Technical report on the findings of task 4 -- Investigation of failed Nitinol brachytherapy wire. Volume 2
- Southwest Research Inst., San Antonio, TX (United States)
This report covers an investigation of the nature and cause of failure in Nitinol brachytherapy sourcewires. The investigation was initiated after two clinical incidents in which sourcewires failed during or immediately after a treatment. The investigation determined that the two clinical Nitinol sourcewires failed in a brittle manner, which is atypical for Nitinol. There were no material anomalies or subcritical flaws to explain the brittle failures. The bend tests also demonstrated that neither moist environment, radiation, nor low-temperature structural transformation was a likely root cause of the failures. However, degradation of the PTFE was consistently evident, and those sourcewires shipped or stored with PTFE sleeves consistently failed in laboratory bend tests. On the basis of the results of this study, it was concluded that the root cause of the in-service failures of the sourcewires was environmentally induced embrittlement due to the breakdown of the PTFE protective sleeves in the presence of the high-radiation field and subsequent reaction or interaction of the breakdown products with the Nitinol alloy.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (United States). Div. of Industrial and Medical Nuclear Safety; Southwest Research Institute, San Antonio, TX (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- OSTI ID:
- 226076
- Report Number(s):
- NUREG/CR-6074-Vol.2; ON: TI96010053; TRN: AHC29610%%118
- Resource Relation:
- Other Information: PBD: Mar 1996
- Country of Publication:
- United States
- Language:
- English
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