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370 Billion Bq of Plutonium equivalent may have escaped from WIPP

Gov’t: Radioactive release “orders of magnitude” worse than predicted at US nuclear dump — 370 Billion Bq of Plutonium equivalent may have escaped from WIPP drum during “thermal runaway” & multiple fires — For amount to be that high, a “significant number” of breached drums is expected (VIDEO) http://enenews.com/govt-actual-radioactive-release-nuke-dump-orders-magnitude-predicted-370-billion-bq-plutonium-equivalent-escaped-wipp-drum-significant-number-nuclear-waste-containers-expected-be-breached-amount?utm_source=feedburner&utm_medium=email&utm_campaign=Feed%3A+ENENews+%28Energy+News%29

Sante Fe New Mexican, Apr 23, 2015 (emphasis added): The head of a team of federal investigators [said] he’s not certain whether more than one drum of nuclear waste contributed to contamination of [WIPP]… The reaction pushed temperatures inside the container to nearly 1,600 degrees, ripping open the drum and scattering radioactive material thatbreached not only the fortified room that held the waste, but WIPP itself, which was designed to never leak… [Officials] would not rule out minor seepage from other drums.

U.S. DOE Accident Investigation Report Phase 2, Radiological Release at WIPP, Apr 2015:

6.4.1 Analysis Summary

• The radiological release… resulted from an exothermic reaction that led to a thermal runaway in drum 68660 [that] exhibited the following fire behaviors: Expanding flame front of material expelled from drum… Ignition of exposed combustibles… Propagation within the waste array by flame impingement… Melting and burning of exposed plastics.
• The combustibles external to the waste containers were ignited… direct fire effectswere limited to Rows 8 through 18… there were multiple small fires that caused direct flame impingement on several waste packages… the fire… caused the migration of contamination throughout Panel 7 [and] significant fire damage.
• A thermal runaway is characterized as a very rapid temperature rise within the container… [This] ultimately… led to failure of the lid… permitting a rapid release of combustible gases and combustible solids.

7.1 Accident Scenarios and Source Term Evaluation

• Source term at Station A should be 10 to 100 times lower than the source term in Panel 7 Room 7… Station A source term is estimated [at] 0.1 plutonium equivalent curies (PE-Ci).
• DOE-STD-5506-2007… recommends a bounding estimate of 1E^-4 ARF [0.0001 Airborne Release Fraction] for a drum over-pressurization without a fire… This release estimate, when applied to the… drum inventory of 2.84 PE-Ci, results in an initial source term released to the room of 2.8E^-4 PE-Ci [0.000284 PE-Ci]… less than 1 percent of the 0.1 PE-Ci source term at Station A.
• The chemical reaction resulting in over-pressurization of the drum described above is similar to the… evaluation of a drum deflagration from hydrogen buildup from radiolysis which assumes burning of material expelled from the drum and a contained burning of material remaining within the drum… [The modeled] release estimate from a drum deflagration is about 3 percent of the 0.1 PE-Ci source term at Station A… the actual amount of material released as measured at Station A was larger than the amount predicted… by almost two orders of magnitude… For either the drum over-pressurization or drum deflagration scenarios discussed above, a much greater airborne source term is possible if the nitrate salts behaved as a combustible dust ignited in air or if a greater fraction of material were ejected and burned.
• The 0.1 PE-Ci source term at Station A can be divided by the range of 0.01 to 0.05 LPFs [Leakpath Factor] to estimate the range of source terms initially released… This results in a range of 2 to 10 PE-Ci [74 to 370 billion Bq] airborne in the room… [I]nventory in drum 68660 [was] 2.84 PE-Ci.
• If drum 68660 released a source term as modeled… a significant number of waste containers would be expected to be breached to cause the 2 to 10 PE-Ci source term estimate… Based on the above estimates… release fractions and deposition in the underground, indicated the release from drum 68660 alone was much larger than what would be modeled… [T]he source term evaluation, using conventional release modeling assumptions, could not conclusively affirm that container 68660 was the sole contributor to the release.

Watch the DOE’s presentation of the report here

May 6, 2015 - Posted by Christina Macpherson | incidents, USA