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Title: Cookoff Modeling of a WIPP waste drum (68660)

Technical Report ·
DOI:https://doi.org/10.2172/1178107· OSTI ID:1178107
 [1]
  1. Sandia National Laboratories, Albuquerque, NM (United States)

A waste drum located 2150 feet underground may have been the root cause of a radiation leak on February 14, 2014. Information provided to the WIPP Technical Assessment Team (TAT) was used to describe the approximate content of the drum, which included an organic cat litter (Swheat Scoop®, or Swheat) composed of 100% wheat products. The drum also contained various nitrate salts, oxalic acid, and a nitric acid solution that was neutralized with triethanolamine (TEA). CTH-TIGER was used with the approximate drum contents to specify the products for an exothermic reaction for the drum. If an inorganic adsorbent such as zeolite had been used in lieu of the kitty litter, the overall reaction would have been endothermic. Dilution with a zeolite adsorbent might be a useful method to remediate drums containing organic kitty litter. SIERRA THERMAL was used to calculate the pressurization and ignition of the drum. A baseline simulation of drum 68660 was performed by assuming a background heat source of 0.5-10 W of unknown origin. The 0.5 W source could be representative of heat generated by radioactive decay. The drum ignited after about 70 days. Gas generation at ignition was predicted to be 300-500 psig with a sealed drum (no vent). At ignition, the wall temperature increases modestly by about 1°C, demonstrating that heating would not be apparent prior to ignition. The ignition location was predicted to be about 0.43 meters above the bottom center portion of the drum. At ignition only 3-5 kg (out of 71.6 kg total) has been converted into gas, indicating that most of the material remained available for post-ignition reaction.

Research Organization:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Organization:
USDOE National Nuclear Security Administration (NNSA)
DOE Contract Number:
AC04-94AL85000
OSTI ID:
1178107
Report Number(s):
SAND-2014-20129-O
Country of Publication:
United States
Language:
English