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Hanford site tank interior
This is the surface of waste found in double-shell tank 101-SY at the Hanford Site in eastern Washington State. The appearance and chemical mixture in each Hanford Site waste tank depends on how the waste was generated and later waste management practices such as liquid evaporation, radionuclide removal, and waste mixing between tanks. The steel pipe was bent during past waste movement during a gas release (‘burp’).” April 1989 Courtesy: Pacific Northwest National Laboratory via wikimedia

What ever happened on this?
Did they vent it? Is it still a risk?

Hanford Nuclear Waste Site at Risk of Hydrogen Explosion, Report Warns: Following report of leaks, nuclear safety board finds dangerous hydrogen build up in waste holding tanks. By Lauren McCauley, staff writer, Common Dreams. Wednesday, April 3, 2013 Tanks at the Hanford Nuclear Reservation, which sits on the Columbia River in Benton County, Washington face dangerous risk of hydrogen build up which could trigger an explosion of radioactive materials, a nuclear safety board announced on Monday.
Storage tanks Hanford Nuclear Facility (Photo: Philo Nordlund via Flickr via Common dreams
Storage tanks at Hanford Nuclear Reservation (Photo: Philo Nordlund via Flickr via Common dreams) https://www.commondreams.org/headline/2013/04/03-1 (entire text at bottom of our post)

Note that Hanford, like its twin Sellafield, are projects with their roots in first fighting the Nazis and Japanese in WWII, and then the USSR during the “Cold War”. This is in Washington State. We leave it to the reader to think over if clean-up would have been faster if it were Washington, DC. And, if Sellafield would be better handled if it were near London.
Warning sign at entry to Hanford Site, Washington. Photo:  TobinFricke, via wikimedia.  Jan 2005.
Warning sign at entry to Hanford Site, Washington State. Photo by TobinFricke in January 2005 via Wikimedia.

Who must pay for all of the costly and dangerous clean-up of Sellafield and Hanford? Will the Germans, Japanese or Russians? No! It is the US and UK taxpayer, of course. These projects were initially secretive. They were not voted on.

Meanwhile, Russia has been “on the dole” for its Cold War nuclear cleanup for years, letting other countries (read tax payers) pay or help pay, even though Russia has a 100% state-owned company called Rosatom which is mining and selling nuclear power all over the world and just bought a uranium mine in Wyoming. As we have previously discussed, Russia is also developing new floating nuclear reactors and more nuclear ships:
Since the end of the Cold War, an internationally-funded race has been on to help Russia secure and destroy its nuclear arsenal as envisioned by the START treaty as well as to help Moscow deal with the environmental consequences of 40 years of preparation for nuclear war. ….numerous programmes …. set up bi-laterally and mulit-laterally with Russia to achieve these goals.” Info at this site: http://www.bellona.org/subjects/Funding_Cold_War_Clean-up
Trinity, First Nuclear Test Explosion, July 16, 1945.  By Jack W. Aeby, Los Alamos laboratory, Manhattan Project
Trinity. First Nuclear Test Explosion, July 16, 1945, USA
It seems that Russia has offered to help clean up Fukushima. Is this for free or do they want to be paid? If the Russians were and apparently are STILL being helped with their nuclear clean-up shouldn’t they pay for the clean-up of Hanford and Sellafield? The current Russian President Putin was a former KGB officer AND his grandfather was cook for Stalin. Russia’s state capitalist regime today appears largely a continuation of the USSR’s state capitalist regime. When are the so-called democracies going to stop robbing their people via taxes to support dictatorships and totalitarian or authoritarian regimes?

Back to the details at hand: Flammable Radioactive Waste

This build up of hydrogen gas appears as a recurrent theme-problem in nuclear waste storage. For good visuals of the potential flammability of hydrogen gas check out our reblog: https://miningawareness.wordpress.com/2013/11/17/60-freeway-reopened-after-fire-erupts-on-hydrogen-carrying-big-rig/ Build up of flammable gas appears a major reason to monitor permanent waste sites for perpetuity instead of dumping, backfilling and closing – at least until and if a new solution is found. There needs to be venting! Granite bunkers, with constant monitoring for leaks of water and radioactive materials, seem the most sensible option. It appears obvious that new above-ground concrete encapsulated wastes risk leaking underneath into the ground and ground-water, if concrete cracks. And concrete does and will crack. Concrete has a limited lifespan.

Problem:

RECOMMENDATION 2012·2 TO THE SECRETARY OF ENERGY Hanford Tank Farms Flammable Gas Safety Strategy Pursuant to 42 U.S.C. § 2286a(a)(5) Atomic Energy Act of 1954, As Amended
Dated: September 28, 2012

Background

The Defense Nuclear Facilities Safety Board (Board) believes that current operations at the Hanford Tank Farms require safety-significant active ventilation of double-shell tanks (DSTs) to ensure the removal of flammable gas from the tanks’ headspace. A significant flammable gas accident would have considerable radiological consequences, endanger personnel, contaminate portions of the Tank Farms, and seriously disrupt the waste cleanup mission. Further, the Board believes that actions are necessary to install real time monitoring to measure tank ventilation flow rates as well as upgrade other indication systems used to perform safety-related functions.

On August 5,2010, the Board sent a letter to the Department of Energy (DOE) outlining issues related to the safety strategy for flammable gas scenarios at the Hanford Tank Farms. In its letter, the Board identified that the safety analyses for accident scenarios used non-bounding values for (1) the radiological inventory of the tanks and (2) the amount of waste that could be released in a major accident. Notwithstanding these non-conservatisms, DOE’s safety analyses show that all of the DSTs generate flammable gas in sufficient quantities to reach the lower flammability limit (LFL) for hydrogen. Further, many of the tanks contain sufficient quantities of gas trapped in the waste such that the LFL could be exceeded if the gas were spontaneously released, which is possible under both normal operating and accident conditions. The current control strategy does not include any measures to periodically release the trapped gases in a controlled manner to preclude the accumulation of flammable concentrations.

DOE’s safety analyses show that the potential flammable gas scenarios warrant a credited safety control due to the dose consequences to workers and the public. Accordingly, the ventilation systems for the DSTs were previously classified as safety-significant and credited in the documented safety analysis for the Tank Farms to address flammable gas scenarios. The revision of the safety analysis approved by DOE on January 21, 2010, and implemented on March 30,2010, reduced the DST ventilation systems from safety-significant to defense-in-depth and replaced them with a specific administrative control (SAC) for flammable gas monitoring.

In its August letter, the Board noted that DOE’s SAC for flammable gas monitoring exhibited a number of weaknesses that collectively rendered it inadequate as a safety control. The reliance on an administrative control in lieu of an engineered feature is also contrary to DOE’s established hierarchy of controls as well as sound engineering practice. Further, the Board noted that a number of other installed systems that are (1) necessary to provide accurate and reliable indications of abnormal conditions associated with flammable gas events, and
(2) serve as a direct input to determining whether an operator action is required were not appropriately classified in accordance with their safety function.

In response to these issues, DOE, in a letter dated February 25,2011, informed the Board that it had revised its decision to downgrade the DST ventilation systems and would take action to restore the systems to their former safety-significant status. Additionally, DOE indicated that the level indication systems for the DST annuli and the double contained receiver tank would be upgraded to safety-significant.

During the last year, the Board reviewed DOE’s progress in meeting these commitments and addressing the Board’s safety concerns. The Board noted that while some improvements had been made to the SAC used for flammable gas monitoring, it remained inadequate as a credited safety control. The SAC is less reliable than an engineered feature, remains susceptible to undetectable false low readings, and lacks independent verification.

Although DOE maintains a commitment to upgrading the DST ventilation systems and other installed non-safety-related instrumentation used to perform safety functions, the Board has concluded that no progress has been made in these areas, and the schedule for upgrades continues to slip. The latest schedule, outlined in a letter to the Board dated April 2, 2012, reflects a commitment to completing the upgrades to three of the five DST ventilation systems by fiscal year 2014. During the Board’s June 2012 review, DOE indicated that even this was no longer a realistic schedule. DOE’s current path forward is to upgrade only one of the DST ventilation systems (AY/AZ Tank Farm) by fiscal year 2015 to support mixer pump testing that is currently anticipated in 2016. No near-term procurement or installation plans are in place for the four other DST ventilation systems. Similarly, no plans or activities are proposed to upgrade the installed non-safety instrumentation systems being used in safety-related applications (e.g., the level indication systems for the DST annuli and the double container receiver tank).

Conclusions

The Board believes that DOE needs to upgrade the DST ventilation systems and other instrumentation systems used for safety-related functions at the Hanford Tank Farms. Further, the continued reliance on an inadequate SAC for flammable gas control presents an unnecessary risk to safety. At this time, DOE does not have a means to provide alternate ventilation if the existing ventilation system becomes inoperable. The hazards posed by flammable gas releases in DSTs and the challenges they pose to any ventilation system are directly proportional to the volume of flammable gas retained within the DST wastes. Reducing the current inventories of flammable gases retained in the DST waste and keeping them small would reduce the future hazards posed by gas release events.

Recommendation

Accordingly, the Board recommends that DOE:

1. Take near-term action to restore the classification of the DST ventilation systems to safety-significant. In the process, determine the necessary attributes of an adequate active ventilation system that can deliver the required flow rates within the time frame necessary to prevent and mitigate the site-specific flammable gas hazards at the Hanford Tank Farms.

2. Take near-term action to install safety-significant instrumentation for real-time monitoring of the ventilation exhaust flow from each DST.

3. Take near-term action to upgrade the existing installed non-safety-related equipment that is being used to fulfill safety functions at the Hanford Tank Farms to an appropriate safety classification. This includes instrumentation and control equipment whose indications are necessary for operators to take action to accomplish necessary safety functions.

4. Identify compensatory measures in case any existing DST ventilation systems become unavailable at the Hanford Tank Farms.

5. Evaluate means to reduce the existing inventory of retained flammable gases in a controlled manner. Since these gases will continue to be generated until the tank contents are processed, evaluate methods to reduce the future retention of flammable gases in these tanks or to periodically mix them to prevent the future accumulation of flammable gas inventories that could cause the tank headspace to exceed the LFL if rapidly released.

The Board urges the Secretary to avail himself of the authority under the Atomic Energy Act (42 U.S.C. § 2286d(e)) to ‘implement any such recommendation (or part of any such recommendation) before, on, or after the date on which the Secretary transmits the implementation plan to the Board under this subsection.’

Peter S. Winokur, Ph.D., Chairman

Excerpts from proposed DOE Solutions, emphasis added. (entire document found here: http://www.dnfsb.gov/sites/default/files/Board%20Activities/Recommendations/Implementation%20Plans/ip_rec-id_20376_1.pdf )

U.S. Department of Energy
Implementation Plan for Defense Nuclear Facilities Safety Board Recommendation 2012-2
Hanford Tank Farms Flammable Gas Safety Strategy

Washington, DC 20585
June 2013

The function of the five primary ventilation systems servicing the 28 DSTs at the Hanford Tank Farms is to remove flammable gases that are generated by the tank waste due to radiolysis, thermolysis, and corrosion. The DST primary ventilation systems maintain the concentration of flammable gases below the LFL in the DST headspace resulting from steady state and induced gas releases due to water additions, chemical additions, and waste transfers into DSTs.

In early 2010, DOE evaluated the DST primary ventilation systems as a preventive system and concluded that flammable gas generation rates were sufficiently low that an active ventilation system was not required, relying instead on flammable gas monitoring and the implementation of ignition controls to protect facility workers. DOE reclassified the DST primary ventilation systems as General Service (GS) equipment in the DSA for the Hanford Tank Farms.

Reliability of the existing flammable gas controls was questioned and in early 2011 DOE revised the DSA to require SS active ventilation. …..

Flammable gases are an ongoing hazard in the Hanford Tank Farms. There are three distinct types of hazards, each with different initiators and different applicable controls: (1) steady state gas accumulation; (2) a spontaneous gas release event; and (3) an induced gas release event.

Steady state gas accumulation occurs when flammable gas builds up in an enclosed space. Steady state flammable gas generation is recognized as an output from the stored Hanford DST wastes and all tanks have passive ventilation, which slows down gas build up. If the accumulation of flammable gas reaches 100 percent of the LFL, it could ignite, resulting in a significant facility worker hazard due to shrapnel, overpressure and chemical exposure. Steady state accumulation is a slow phenomenon allowing the active ventilation to remove the flammable gases.

A spontaneous gas release event occurs when flammable gas accumulates in the waste solids to the point where the solids experience a buoyant displacement gas release event (BDGRE). Five tanks (AN-103, AN-104, AN-105, AW-101 and SY-103) currently have the rheological properties to support a spontaneous BDGRE. If the flammable gas in the headspace due to the BDGRE were to exceed 100 percent of the LFL, it could ignite, resulting in a significant facility

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worker hazard. Data on these tanks show that to date they have never had a release that approached the LFL and the size of the releases has been decreasing. The only tank that has ever experienced a large gas release event that exceeded 100 percent of the LFL was 241-SY-1O1; there was no ignition of the gas and no significant worker impact. The last SY-101 gas release event was in June, 1993; the tank waste has since been remediated by transfers and dilution. Tank SY-101 no longer has the waste properties that make a BDGRE possible since the highly concentrated salt crust and supemate have been diluted and material transferred out of the tank with the overall supemate specific gravity reduced from 1.5 to 1.1.

Hydrogen generation rates have been calculated for all 28 Hanford DSTs; the calculated rates range from 0.73 ft3/day up to 81 ft3/day. The calculated ventilation flow rate needed to maintain DST vapor space below 25 percent LFL ranges from < 0.1 ft3 /min to < 7 ft3 /min, and the flow rate to maintain tank vapor space below 100 percent LFL ranges from< 0.01 ft3/min to< 2 ft3 /min. The AY and AZ tanks have the highest generation rates for all DSTs. Tank AY-102 has the highest generation rate of all of the DSTs. The gas accumulation in this tank could reach LFL, with no ventilation flow, within approximately 20 days. The ventilation flow rate in this tank would need to be approximately 1.4 to 1.5 ft3 /min to stay below the LFL.

All other DSTs require less than half that ventilation rate to stay below the LFL. This slow buildup of flammable gases is one of the reasons why a tailored approach to upgrading the DST ventilation system to SS is pragmatic and appropriate.

The third type of flammable gas release is an induced gas release event. This may occur when a significant amount of flammable gas accumulates in waste solids and an Operational or external event causes a waste disturbance resulting in a release of the retained gas. Eleven DSTs have waste properties that could result in an induced gas release event. The only currently authorized activities that can induce such a release are water additions, chemical additions, or waste transfers, that result in dissolution of precipitated salts resulting in the release of any gas trapped in the salt.

A special case is a seismically-induced gas release event. The hazard of a seismically-induced flammable gas accident is limited to a subset of five DSTs (AN-103, AN-104, AN-105, AP-108 and SY-101) that are evaluated to potentially reach 100 percent of the LFL in the tank headspace. In a seismic event, a simultaneous gas release could occur and the active ventilation system would provide only a limited benefit since the release and ignition could be concurrent. In this case, the facility worker is protected by the existing requirement to evacuate the tank farms during the seismic event. Tank farm reentry and flammable gas monitoring would be performed in a controlled manner as part of the event response.

In order to support waste feed delivery to the WTP that will meet WTP waste acceptance criteria, mixer pumps are being designed and will eventually be installed at the Hanford Tank Farms. The operation of these pumps will add another activity that could result in an induced gas release event. Mixer pump operations have the potential to release the trapped gas at a rate much higher than is possible from salt dissolution. In addition, mixer pump operation will add significant quantities of energy as heat into the waste. As the temperature of the waste increases, the rate of

gas generation increases. Thus, DOE has committed to upgrade the DST active ventilation systems to support future mixer pump operations (DOE ORP letter from J.D. Dowell to Tim Dwyer, DNFSB, "Path Forward for Hanford Tank Farms Double-Shell Tank (DST) Ventilation System," 11-0RP-004, dated February 10, 2011). Due to the slow flammable gas generation rates, a phased approach is being used as described below.

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As the first step, in February a safety basis amendment was implemented that treated the DST primary tank ventilation system like a SS control for the steady state and induced gas release hazards. The amendment requires, for steady state flammable gas hazards, that the flow from each tank be measured annually and immediately after repositioning a tank outlet isolation valve or a flow control valve (depending on the individual ventilation system). The required air flow rate exceeds the flow rate needed to maintain the headspace below 25 percent of the LFL by a factor of five to account for small changes that can impact the flow rate (e.g., High-Efficiency Particulate Air (HEPA) filter loading). The flow rate is measured using hand held probes.

For waste transfers that require induced gas release event controls, the flow will be verified prior to the transfer and once every 30 days thereafter (the frequency is based upon the potential impact of changes to the individual flow rate, including tank air in-leakage and HEPA filter loading). The flow rate will also be measured immediately after repositioning a tank outlet isolation valve (for AN, AP, AW and SY Farms) or a flow control valve (for AY and AZ Farms). In addition to the periodic flow rate verification, the tank headspace is checked every two hours to ensure it is still under vacuum. The revised controls require an operating DST primary tank ventilation system train and an operable back-up DST primary ventilation system train. In addition, a series of planned improvements are documented in the safety basis that are necessary for the DST primary tank ventilation systems to document and fulfill the critical characteristics needed to be fully qualified as a SS system.

Ongoing primary ventilation systems in the AZ/AY, SY, and AP Tank Farms will be upgraded to SS as a planned improvement with functional requirements driven by mixer pump operations. This includes significant modifications to the current systems (if not complete replacement), as well as the installation of permanently installed SS instrumentation to monitor ventilation flow through each tank (measured at the tank outlet) and the provision for installation of a SS backup power system for each ventilation system.

The two ventilation systems servicing the remaining DSTs (AN and AW Tank Farms) were recently replaced, although not as SS. They will be upgraded to SS status through the process for upgrading existing systems and equipment, again to support mixing operations in these DSTs. The TOC will identify the critical characteristics of system components that are required for the system to be designated as a SS system, and document how the system meets the critical characteristics. This includes the installation of permanently installed SS instrumentation to monitor ventilation flow through each tank (measured at the tank outlet) and the ability to provide SS backup power for each ventilation system. These are the most recently installed ventilation systems in the Hanford Tank Farms.

3.0 Summary of DOE Proposed Actions

The Board acknowledged in its Recommendation that some improvements had been made to the Specific Administrative Controls (SACs) used for flammable gas monitoring, but stated that the control remained an inadequate safety control and presented an unnecessary risk to safety. DOE has committed to making the ventilation system SS, but more work is needed to make the ventilation system a credited safety control.

DOE will implement more robust engineered SS flammable gas controls, both in the near term and in the future, to upgrade the remaining portions of the DST primary ventilation systems classified as SS Structure, System and Components (SSCs) to support mixer pump operations for tank waste feed to the WTP. DOE will use a phased approach to address the five sub-recommendations of the Board in order to better define near-term objectives and long-term goals to protect facility workers throughout the lifespan of the Hanford Tank Farm mission. This approach has been subdivided into the following three phases: …..

Phase 1: Improved Monitoring and Administrative Controls
……… [details at original]

Phase 2: Implementing SS Flow Monitoring

A major improvement in flammable gas control strategy will be the installation of SS instrumentation for real-time monitoring of the ventilation exhaust flow from each DST….
[see original]

Phase 3: Mixer Pump Operations at the Hanford Tank Farms ….. [see original]
……
The revised safety basis documents the planned improvements needed to upgrade the DST primary tank ventilation systems to meet safety significant requirements to prevent hazards due to the steady state generation of flammable gas and induced gas releases caused by planned solids dissolution and/or future waste mixing. Among these planned improvements, the installation of SS instrumentation for real-time monitoring of the ventilation exhaust flow from each DST provides the greatest benefit and thus is given the highest priority (See sub-recommendation 2 discussion below).

DOE has directed the TOC to develop the following approach for upgrading the DST primary tank ventilation systems on a priority basis.

Provide simplified back-up power systems and architecture that allows the Variable Frequency Drives (VFDs) and the basic process control system to be bypassed, thereby streamlining the current planned improvements related to emergency diesel generator systems, SS VFDs and SS control systems. • Develop non-destructive examination methods to inspect the below grade ductwork. • Complete the system interaction (two over one) evaluations. • Eliminate single active failures in interfacing systems that could prevent operation of both primary tank ventilation system trains.

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• Replace the existing AP and SY primary tank ventilation systems with the units that have been procured and are on site. Given that these units were procured as GS, the planned improvements discussed above are included in this activity
.
….
Sub-recommendation 2: Take near-term action to install safety-significant instrumentation for real-time monitoring of the ventilation exhaust flow from each DST.
……
Each type of instrument selected will be installed on two different tanks to demonstrate that real-time flow measurements can be taken. The tank selection process also used a decision analysis approach, which rated all 28 DSTs in order to make a final selection of AZ-102 and SY-102 as the test locations. The test is planned to include 3 months of data gathering. The 3-month duration was selected based upon experience at the Hanford Tank Farms and the conditions (e.g., humidity, material carryover, and harsh chemical additions) which challenge the instruments over time. The test program will ensure the chosen instruments perform satisfactorily and potentially avoid significant
……
Sub-recommendation 4: Identify compensatory measures in case any existing DST ventilation systems become unavailable at the Hanford Tank Farms.

DOE Implementation: On February 21, implementation of a safety basis amendment was completed. This amendment requires an operating DST primary tank ventilation system train (except for outages not to exceed 24 hours). To emphasize the importance of operating the DST primary ventilation systems continuously, limiting conditions for operation (LCO) are in place with required actions to restore ventilation in the event the primary tank ventilation system train is inoperable. In addition, the amendment requires a standby train that can be started within 8 hours (except for outages not to exceed 10 days). Should both the primary and standby train be inoperable, an LCO Action requires increased flammable gas monitoring (every 72 hours after the initial reading). Actions, including ignition controls, must be taken prior to the concentration of flammable gas exceeding 60 percent of the LFL. Furthermore, if there is an induced gas release hazard in a DST being ventilated by the system, the applicable LCO requires that any ongoing water additions, chemical additions, or waste transfers must be stopped within 4 hours if

active ventilation is lost. Stopping the addition/transfer limits the induced gas release rate from the dissolution of soluble settled solids to rates that are encompassed within the LCO Actions for the normal steady-state flammable gas hazard.

As part of phase 3 discussed in section 3.0, above, DST ventilation systems will be upgraded or designed and procured as SS. Completion of the planned improvements for each of the DST primary tank ventilation systems will document the necessary attributes of each system to meet the functional requirement of a SS system. That will include the applicability of redundant electrical power or a supplemental portable ventilation system to provide compensatory measures. Simplified back-up power systems and architecture would allow the VFDs and the basic process control system to be bypassed, thereby streamlining the current planned improvements related to emergency diesel generator systems, SS VFDs, and SS control systems.
……
Sub-recommendation 5: Evaluate means to reduce the existing inventory of retained flammable gases in a controlled manner. Since these gases will continue to be generated until the tank contents are processed, evaluate methods to reduce the future retention of flammable gases in these tanks or to periodically mix them to prevent the future accumulation of flammable gas inventories that could cause the tank headspace to exceed the LFL if rapidly released.

DOE Implementation: Initial evaluation of approaches to address this concern are being performed. DOE will direct the contractor to evaluate potential means to reduce the inventory of retained flammable gases in DSTs in a controlled manner. This evaluation will consider methods to perform periodic mixing operations and other options to reduce gas retention (building upon the lessons learned from remediation of 101-SY, reference WHC-EP-0516, Mitigation/Remediation Concepts for Hanford Site Flammable Gas Generating Waste Tanks).

Milestones and Deliverables:

Action 5-1: Evaluate potential means to reduce the inventory of retained flammable gases in DSTs in a controlled manner.

Deliverable: A report evaluating potential options for reducing the inventory of retained flammable gases in DSTs in a controlled manner.
Expected Delivery Date: June 2014

Lead: Assistant Manager, Tank Farm Project

In summary, the DOE considers that these actions are technically and economically appropriate to achieve the overall objective of reducing the risk posed by flammable gas events at the Hanford Tank Farms and implement the overall intent of Board Recommendation 2012-2 in a manner commensurate with the risk. ” Emphasis added. The entire document is here (includes more implementation dates): http://www.dnfsb.gov/sites/default/files/Board%20Activities/Recommendations/Implementation%20Plans/ip_rec-id_20376_1.pdf

Some additional info:
http://www.dnfsb.gov/board-activities/recommendations/hanford-tank-farms-flammable-gas-safety-strategy

The above documents pretty much speak for themselves as to the flammability of the waste; need for ventilation, and US Dept. of Energy foot-dragging. One of the most striking things is that they say: Tank AY-102 has the highest generation rate of all of the DSTs. The gas accumulation in this tank could reach LFL, with no ventilation flow, within approximately 20 days. LFL — Lower Flammability Limit. So with lack of ventilation it could have a problem quickly. It is also interesting that they say the workers would not be in danger during an earthquake because they would leave the area. Since when is there an earthquake warning? Does this make sense to anyone else?

Do they filter the vented air? It seems that either they do or will with HEPA filters

Complete Commons Dreams Article:
Hanford Nuclear Waste Site at Risk of Hydrogen Explosion, Report Warns: Following report of leaks, nuclear safety board finds dangerous hydrogen build up in waste holding tanks By Lauren McCauley, staff writer, Published on Wednesday, April 3, 2013 by Common Dreams
Tanks at the Hanford Nuclear Reservation, which sits on the Columbia River in Benton County, Washington face dangerous risk of hydrogen build up which could trigger an explosion of radioactive materials, a nuclear safety board announced on Monday.

The Defense Nuclear Facilities Safety Board expressed these concerns in a briefing letter to Sen. Ron Wyden (D-Ore.), chairman of the Senate Energy and Natural Resources Committee, who sought the board’s review ahead of next week’s confirmation hearing for President Obama’s Energy Secretary nominee Ernest J. Moniz—a known nuclear-hawk.

The board expressed concern over the potential for hydrogen gas buildup within the underground tanks, particularly those ‘double wall’ tanks which contain the highly radioactive material that was previously pumped out of leaking single-shell tanks.

‘All the double-shell tanks contain waste that continuously generates some flammable gas,’ the board said. ‘This gas will eventually reach flammable conditions if adequate ventilation is not provided.’

Earlier this year, investigators found six single-shelled underground storage tanks leaking up to 1,000 gallons of radioactive sludge each year—a situation that noted theoretical physicist Michio Kaku called a ‘ticking time bomb.’

According to the Associated Press, officials have known about the explosive potential of the hydrogen gas build up and last fall the Defense Nuclear Facilities Safety Board recommended additional monitoring and ventilation of the tanks, which federal officials have been working to implement.

Federal officials have thus far evaded any long term, sustainable clean up of the 56 million gallons of highly radioactive material currently held at the former Manhattan Project site.

During their review, the board also noted that the waste treatment plant, which is currently being constructed for long-term waste disposal, faces serious technical problems which could lead to ‘chemical explosions, inadvertent nuclear reactions and mechanical breakdowns,’ the New York Times reports.

In an interview Tuesday, Wyden said that the board’s experts had raised “a serious question as to whether this plant is going to work at all.”

‘The next Secretary of Energy – Dr. Moniz – needs to understand that a major part of his job is going to be to get the Hanford cleanup back on track, and I plan to stress that at his confirmation hearing next week,’ Wyden added.
_____________________
This above Commons Dreams article is licensed under a Creative Commons Attribution-Share Alike 3.0 License
https://www.commondreams.org/headline/2013/04/03-1

On February 19, 1991, the Seattle Times reported that one of the Hanford waste tanks was about to vent. It had been venting on average every quarter, with the last having been October 23, 1990!