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IHS Energy Daily

Gas buildup in waste drum prompts state order to Los Alamos
(reprinted here by permission)


The head of the New Mexico Environment Department last month ordered Los Alamos National Laboratory to resume daily monitoring of gas buildup in two transuranic waste containers stored at the Energy Department nuclear weapons facility after one of the containers was found to contain elevated hydrogen concentrations representing 70 percent of the minimum level posing a threat of explosion, IHS The Energy Daily has learned.

The August 29 directive from New Mexico Environment Secretary Ryan Flynn came one day after Los Alamos officials informed the state agency that they had discontinued daily monitoring of gas levels in the container— called a “standard waste box”—and would instead monitor the “headspace” of the box twice a week.

In a letter ordering the resumption of daily gas monitoring in that box and another waste container at the lab, Flynn also revealed that Los Alamos decided to reduce the frequency of gas monitoring even though it knew about the elevated hydrogen levels in one of the waste boxes.

The high gas levels are notable in that the waste box contains nitrate salt wastes similar to those in a waste drum that erupted in February at the Waste Isolation Pilot Plant (WIPP), releasing radioactivity from DOE’s underground New Mexico nuclear waste disposal repository.

To date, DOE officials and Los Alamos National Security (LANS), the contractor that operates Los Alamos for DOE, say they have not been able to determine what caused the energetic drum breach at WIPP, which dislodged the drum’s lid and left scorch marks on its side.

And until Flynn’s August 29 letter, neither DOE nor LANS had disclosed publicly the elevated hydrogen levels in the waste box, which Flynn said the Nex Mexico Environment Department (NMED) only learned about after LANS told NMED it would reduce the frequency of gas monitoring for at least two drums stored at the lab.

“During conversations with [Los Alamos], NMED has become aware that at least one standard waste box (Container SB50522) with a container of remediated nitrate salt-bearing waste has elevated concentrations of hydrogen gas and carbon dioxide,” Flynn told top Los Alamos officials in the letter.

“[Los Alamos officials] have informed NMED that they had been collecting daily headspace gas sampling and hourly temperature measurements for container SB50522. On August 28, 2014, [Los Alamos] verbally informed NMED that they had reduced the frequency of headspace gas sampling on this container from daily to twice per week.

“[Los Alamos] shall resume daily headspace gas sampling of this container effective immediately,” said Flynn.

He also said the lab told the state on August 28 that it had reduced the frequency of gas monitoring on another waste container identified as 68685, and Flynn ordered the resumption of daily monitoring on that as well.

Flynn also detailed the hydrogen gas levels in container SB50522, saying Los Alamos had found hydrogen concentrations as high as 28,000 parts per million (ppm), or about 70 percent of the “lower explosive level” calculated for that drum. Los Alamos also said carbon dioxide levels in the container had reached as high as 76,000 ppm.

Flynn said Los Alamos officials believed that the ratio of hydrogen to carbon dioxide in the waste container indicated that the elevated gas levels were the result of radiolysis, the normal radioactive decay of waste materials in the drum.

Flynn in his August 29 letter asked for an explanation of why Los Alamos thought radiolysis was responsible for the elevated gas levels in the drum, and what the lab would do if hydrogen concentrations went higher. He said Los Alamos officials have “stated that 35,000 ppm (approximately 87.5 percent of the lower explosive level) for hydrogen is an ‘action level,’ but did not describe any specific actions that will be taken.”

Flynn also ordered modifications to Los Alamos’ plans for safeguarding waste drums similar to the breached WIPP drum. He directed the lab to conduct daily gas monitoring of any drum reaching 20,000 ppm of hydrogen, and to lower its action level to 30,000 ppm and explain what specific actions it will take if hydrogen concentrations rise to that level in a drum.

Beyond the elevated hydrogen gas levels, Flynn once again asked Los Alamos to explain its recent action reclassifying dozens of nitrate salt-bearing waste drums at the lab as potentially containing ignitable or corrosive wastes. The lab wrote NMED last month to “provisionally” reclassify the drums, which Los Alamos previously believed did not contain wastes with those potentially dangerous characteristics.

Los Alamos was required to notify NMED of the reclassification under the hazardous waste permit granted to the lab by NMED. Officials at WIPP also reclassified Los Alamos waste drums containing nitrate salts that are disposed of in underground chambers at that facility, and Los Alamos also recently told NMED it was reclassifying drums it sent to Waste Control Specialists, a commercial low-level nuclear waste disposal facility in Texas.

The broad reclassification of drums is important because it may indicate that other drums at Los Alamos and WIPP are volatile like the breached WIPP drum.

However, Flynn has appeared to question the basis of Los Alamos’ reclassification decision, asking the lab to explain and justify what he called its “speculation” that the drums had ignitable or corrosive wastes.

In a September 5 response to Flynn’s inquiry about the reclassification, Los Alamos revealed that it had tested waste taken from one drum stored at the lab’s Area G that contains unremediated nitrate salt-bearing waste, and that results from that testing received May 22 showed “the presence of nitrate compounds listed on the U.S. Department of Transportation Division 5.1 oxidizers table.” Oxidizers are compounds that can ignite in certain chemical reactions and are classified under federal hazardous waste rules as D001 wastes.

“Although the analytical results apply to only one unremediated drum, [Los Alamos] determined to conservatively label the remaining drums with the D001 hazardous waste number,” the lab told NMED.

The lab also said it believed drums containing remediated nitrate salt-bearing wastes were ignitable because the wastes had been mixed with organic kitty litter to soak up potentially dangerous liquids prior to disposal; the organic kitty litter inexplicably was used in place of inorganic kitty litter previously specified in Los Alamos waste disposal procedures because it was known to be unreactive.

Los Alamos told NMED it had been unable to get a sample of the remediated nitrate salt-bearing waste in its drums, but that it had tested surrogate materials similar to those wastes in late July, and that the tests showed the surrogates “could be classified as oxidizers.” As a result, Los Alamos said it conservatively reclassified all its remediated nitrate salt-bearing wastes as oxidizers until more testing could be done to definitively determine if those wastes are oxidizers.

Los Alamos told Flynn it reclassified some of the 29 drums containing unremediated nitrate salt-bearing waste as possibly containing corrosive wastes—making them regulated hazardous wastes—because some of the drums were packed with liquid wastes known to be acidic. Further, the lab said 26 of the 29 drums contained liquids.

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