The University of Washington Cesium Release

This sad tale has some major information gaps. If anybody can fill in these gaps, please get in touch with me.

The National Nuclear Security Administration (NNSA) has instituted a taxpayer funded program to replace Cesium-137 based blood irradiators with electron driven xray devices.¹ Blood irradiators have a range of uses; but their main job is to zap donor blood to kill any disease viruses and inactivate the donor's immune cells to enable a successful transfusion. Whether the weaker xray based machines work as well is not at all clear. I will let others debate that issue; but give me cesium blasted blood.

The NNSA's worry is that the cesium-137 will end up in terrorist hands and be used to produce a dirty bomb. Dirty bombs, scattering radioactive material with an ordinary explosive, depend on radiophobia to strike fear into the multitudes, causing panicked evacuations and massive psychological distress which of course the NNSA promotes by telling us dirty bombs are so dangerous that we need to change out perfectly good blood irradiators at great expense. In fact, just about all analyses of dirty bombs indicate if the blast doesn't kill you, neither will the radiation.² The Israelis confirmed this in a series of tests in the Negev desert.³

In any event, in 2019 the University of Washington(Udub) decided to take advantage of the subsidy and change out the blood irradiator at their Harborview Facility.

Cesium-137 blood irradiators are very powerful radiation sources and must be handled carefully. The Harborview source as delivered in 2003 could deliver a dose rate of 100,000 mGy/h 30 cm from the source. These are the kind of dose rates you need to kill viruses. The manufacturers of the machine were aware of this. They provided sufficient shielding so that, when the device was delivered, the dose rate at the surface was 0.007 mGy/h. By 2019, this had dropped to about 0.005 mGy/h, 8 times less than the 0.040 mGy/h tolerance dose rate. The shielding required to do this meant the irradiator weighed 5,800 pounds.

In a rational world, the 6000 pound machine would be picked up by a forklift, lifted on to a truck, and driven to where ever the NNSA is keeping all the Cesium-137 under lock and key. End of story. Figure 1 shows the first part of this process. Check out the guys walking around the blue irradiator.

Figure 1 Forklift moving irradiator to the Mobil Hot Cell.

But this is nuclear; so bring in the clowns, very expensive clowns. Udub put the job out to bid. But since this is nuclear, they only got two quotes, for what should have been a simple trucking job. Very few outfits have the regulatory bona fides to move Cs-137 around. One bidder proposed something similar to the put it on a truck and take it away; but backed up by all sorts of analyses and paperwork demonstrating that moving the device in its own shielding would meet NRC/DOE/DOT requirements.

The other bidder, International Isotopes Inc (INIS), had a cheaper plan. They would extract the 107 TBq source from its shielding at the hospital, and remove a long lifting rod. This would allow them to put the source in a smaller cask, which would then fit into a standard DOT approved transport cask. INIS's plan avoided all the paperwork associated with non-standard shielding. It was the low bidder and got the job. INIS called their plan over-encapsulation. Nuclear contractors are great at coming up with misleading terminology.

To open up the source, INIS would use a makeshift Mobile Hot Cell. They decided to do the work in the building's loading dock. Then commenced a tromedy of errors. They could not get the irradiator to mate with the hot cell properly. One problem was some left over studs from the removal of an anti-theft device on top of the irradiator. These were not ground down because they did not have a hot work permit. So they stuck the irradiator under the hot cell at 90 degrees to the original plan, Figure 2. I'm not making this up.

Figure 2. Planned and actual orientation of irradiator under Mobile Hot Cell.

This left a substantial gap between the top of the irradiator and the bottom of the hot cell, Figure 3. There were about ten high paid observers from the various bureaucracies involved in attendance. Apparently none of them attempted to halt the unfolding fiasco.

Figure 3. Gap between the top of the irradiator and the Mobile Hot Cell.

The lifting rod would not unscrew from the source tube, so INIS decided to saw it off. All this work was being done by manipulators, blind except for TV cameras. They did not know the dimensional details of the source tube.⁴ They ended up cutting into the source itself. Figure 4 shows the damage. Since the top of the source tube was occupied by a threaded tungsten plug and an aluminum spacer, I think only cut Number 3 actually hit cesium.

Figure 4. Damage to the top of the Source Tube

The cesium-chloride was originally a pressed solid; but over time the radiation had turned that into a fine, talcum-like powder. Some of the cesium powder fell onto the top of irradiator. This combined with the gap between the irradiator and the Mobile Hot Cell produced a wedge of radiation, as shown in Figure 5.

Figure 5. Radiation wedge emanating from gap between irradiator and the hot cell.

Some of the fine powder escaped through the gap and into the rest of the building. The building HVAC system was not turned off, until about two hours after the source tube breach. About three hours after the breach, they managed to get the source into its new tube, and then into the INIS transfer cask.

A number of random air dose rate measurements appear to have been taken during this process. But the DOE report only tells us what is on Figure 5. We are told that at 23:50, Udub personnel ``conducted radiological surveys of the area" but we are not given any dose rates. At 00:56 May 3rd, the Seattle Fire Department HAZMAT Team ``conducted surveys". Once again no dose rates. At 19:07 the RAP8 (Radiological Assistant Program) team arrived from Hanford. The DOE report contains this cryptic comment.

RAP8 identified multiple independent HVAC systems in the HRT [Harborview Building], but only the main building HVAC system had been shut down. Consequently, they set up air monitoring stations at locations throughout the HRT. The initial samples did not identify airborne contamination.⁵[p 62]

Once again no dose rates, but the last sentence is not exactly alarming.⁶

We do know that the RAP8 team was so unimpressed, that they went back to Hanford on Sunday May 5th, after being on site for a little more than a day. The DOE report emphasizes that cesium contamination was found throughout the building. Presumably this is the result of swipes. But what counts is the dose rates.

The official DOE report gives us no personnel doses. But a separate DOE summary says the release was less that 1 Ci (37 GBq), and the worst case dose to an individual was 0.55 mSv. The latter was based on urine samples, so it's only his internal dose. The key INIS guy was leaning over the hot cell for the better part of four hours.

In any event, the building was shut down for two years. Udub brags that their cleanup spec was a max of 0.01 mGy per year, a mere 36,500 times below the 1 mSv per day tolerance dose.⁷ The background air dose rate in Seattle is about 0.8 mGy/y, and bounces up and down all the time by +/-0.08 mGy/y. I have no idea how they determined they satisfied this medically ridiculous spec. Some sources put the total cost of the release and clean up at 100 million dollars, others say only 60 million.

What should have happened was

1) as soon as the source was transferred, move the hot cell and the empty irradiator outside the building,

2) turn the building's HVAC system up full blast in full ventilation mode, blowing out any ``contaminated air".

Everybody goes back to work on Monday.

Takeaways

This fiasco begs any number of questions.

1. Why are we allowing bogus fear of dirty bombs to push us to replace perfectly good gamma sources at great expense, while at the same time reinforcing this bogus fear? A far better option would be to educate the public on the effects of a dirty bomb. But this would put a portion of the NNSA out of business.

2) We are paying for this nonsense. We should be able to compare what Udub paid INIS with the cost a moving a 6000 pound machine across the country. Why are we not told the competing quotes for removing the irradiator?

3) Radiation harm is all about the numbers. Radiation is everywhere. Everything including all of us are ``contaminated". Why are we not told the dose rates in the ``contaminated" areas? The DOE is promoting the idea that radiation is binary. Either we have contamination or we don't, and any contamination is intolerable. The enemy is us.

4) It was patently nuts to open up the source on site, when it was already encapsulated in perfectly good shielding. How can regulation be so screwed up that it makes this nonsensical move cheaper than simply putting the irradiator on a truck?

5) The DOE report pontificates over and over about lack of safety culture, meaning INIS did not carefully follow its own procedures for opening up the source. But everybody involved, NRC, DOE, DOT, the Washington Department of Health, and Udub knew or should have known there was no need to open up the source. Why did nobody object to this nonsense? The lack of real safety culture goes far higher than INIS. We do not have a nuclear safety culture. We have a cover-your-ass regulatory culture. It is killing US nuclear.

Postscript

Here's the worst part. I can defend the indefensible Udub clean up spec. Udub has plenty of people who understand radiation. But they also know 40%+ of the people who work in that building will eventually get cancer. Everyone of those cancer victims will be hounded by a tort lawyer, explaining how much money an unfeeling employer who left them in a radiation contaminated lab should pay them for their suffering. Udub isn't paying for the cleanup. The silly cleanup spec makes perfectly good sense in a lawyer infested society. That is how screwed up things are.

So to be more precise. We have a cover-your-ass regulatory culture in a lawyer infested society.

1. It appears the Cesium Irradiator Replacement Program is costing us about $25 million per year.

2. Socol, Y. et al. Assessment of probable scenarios of radiological emergency and their consequences, International Journal of Radiation Biology, Vol 10, 2020.

3. Levinson, C. Israel tested Dirty Bomb Clean up in the Desert, Haaretz, June, 2015.

4. J L Shephard were the manufacturers of the irradiator. They regarded the dimensions as proprietary and demand money for the data, which INIS decided not to pay.

5. Joint Investigation Report, Sealed Source Recovery at the University of Washington Results in Release of cesium-137 on May 2, 2019, DOE, March, 2020.

6. Someone has these measurements. Sounds like they were background.

7. Conservatively assuming the absorbed dose rate is the same as the ambient air dose rate.