Type B investigation of the iridium contamination event at the High Flux Isotope Reactor on September 7, 1993
On the title date, at ORNL, area radiation alarms sounded during a routine transfer of a shielding cask (containing 60 Ci{sup 192}Ir) from the HFIR pool side to a transport truck. Small amounts of Ir were released from the cask onto the reactor bay floor. The floor was cleaned, and the cask was shipped to a hot cell at Building 3047 on Oct. 3, 1993. The event was caused by rupture of one of the Ir target rods after it was loaded into the cask for normal transport operations; the rupture was the result of steam generation in the target rod soon after it was placed in the cask (water had entered the target rod through a tiny defect in a weld while it was in the reactor under pressure). While the target rods were in the reactor and reactor pool, there was sufficient cooling to prevent steam generation; when the target rod was loaded into the dry transport cask, the temperature increased enough to result in boiling of the trapped water and produced high enough pressure to result in rupture. The escaping steam ejected some of the Ir pellets. The event was reported as Occurrence Report Number ORO--MMES-X10HFIR-1993-0030, dated Sept. 8, 1993. Analysis indicated that the following conditions were probable causes: less than adequate welding procedures, practices, or techniques, material controls, or inspection methods, or combination thereof, could have led to weld defects, affecting the integrity of target rod IR-75; less than adequate secondary containment in the cask allowed Ir pellets to escape.
- Research Organization:
- Martin Marietta Energy Systems, Inc., Oak Ridge, TN (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 10139742
- Report Number(s):
- DOE/OR-2004; ORNL/M-3175; ON: DE94009446; TRN: 94:007530
- Resource Relation:
- Other Information: PBD: Mar 1994
- Country of Publication:
- United States
- Language:
- English
Similar Records
Consequence Analysis of Residual Water in a Storage Canister (Preliminary Report)
Modeling fission product release from ruptured LWR fuel rods
Related Subjects
07 ISOTOPES AND RADIATION SOURCES
IRIDIUM 192
ISOTOPE PRODUCTION
RADIATION ACCIDENTS
HFIR REACTOR
FAILURE MODE ANALYSIS
TARGETS
CASKS
CONTAMINATION
220900
220600
070500
REACTOR SAFETY
RESEARCH
TEST
TRAINING
PRODUCTION
IRRADIATION
MATERIALS TESTING REACTORS
HEALTH AND SAFETY