Accessibility Information and Accesskeys | Skip navigation
16/9/2012 - Uranium 233 / 238 Inhalation Overexposure

This is taken from the IAEA News Channel (Nuclear & Radiological Events)

Uranium 233 / 238 Inhalation Overexposure

 

[01 October 2011, USA, University of Nevada , posted 05 September 2012, INES = 2 (Provisional)]

A graduate student inhaled a mixture of U-233 and U-238 while working in a lab grinding a compound of uranium octoxide. The student used a glove box instead of a hood with a high-efficiency particulate air (HEPA) filter, contrary to the University of Nevada Las Vegas approved procedure. This happened twice, possibly between October 1, 2011 and April 1, 2012.

The first bioassay, based on an inhalation date of October 1, 2011, resulted in a dose of 177.2 mSv (17.72 rem) total. When the inhalation date was assumed to be April 1, 2012, the result was 55.2 mSv (5.52 rem). The student will be given a third bioassay on September 5, 2012, that will involve a low-energy chest count to detect Th-234, and an organ count to detect any uranium in the kidneys.

The student has been restricted from all lab work since April. NRC EN48261.


The incident log for the above event can be read at the following link: IAEA News Channel.

Ionactive Comment

Not pleasant for sure. What I find interesting here is the fact that whilst many think the nuclear industry is secretive (and this is NOT a nuclear industry incident), it is still recorded on the IAEA Nuclear and Radiological Events website. How many other students have inhaled all sorts of much nastier non-radioactive chemicals etc, and have no idea of the consequences (or indeed that the exposure had taken place at all)?

At least in this case, using standard internal radiation exposure models, the student has an idea of the overall committed risk. Clearly the experimental protocol, risk assessment (was there one?), equipment used, training and supervision are all suspect.

7/7/2012 - Worker overexposure - Co-60

This is taken from the IAEA News Channel (Nuclear & Radiological Events)

Worker overexposure

 

[19 April 2012, Greece, Greek Atomic Energy Commission , posted 04 July 2012, INES = 2 (Final)]

The Ionizing Radiation Calibration Laboratory (IRCL) of the Greek Atomic Energy Commission (GAEC) is equipped with a Co-60 irradiator, used for calibration purposes of radiotherapy dosimeters. In the period 19 - 25 April 2012 the replacement of the Co-60 source (nominal radioactivity of 20 TBq -April 2012) with a "new" Co-60 source (nominal activity of 110 TBq - April 2012) was conducted. The technical part of the source reloading was fully undertaken by the manufacturer of the irradiator (from abroad), who, also, provided the technical personnel (two technicians). Staff members of GAEC were present and supervised the works.

On 19 April 2012, the technicians started the replacement procedure which consisted of three steps:

• alignment of the source container to the irradiator head. Due to the position of the irradiator, which produces radiation beam at horizontal direction, the source container was suspended from a rigid steel frame (crane), in order to level the container and the irradiator head. This step was completed successfully on 19 April 2012.
• removal of the "old" source from the irradiator head and transfer into the safe position inside the source container. It was completed successfully on 19 April 2012 after overcoming a few technical difficulties.
• reload of the "new" source into the irradiator head. While driving the source into the head, it was stuck inside the sleeve (holding the source) in an unknown position within the container; During this process the shielding plugs had been removed, resulting levels of radiation inside the banker around 1.5 mSv/h (scattered radiation) and a few Sv/h in the primary beam. One of the technicians (referred to hereafter as A) had to work - for very short periods of time (i.e. seconds) - within the primary beam in order to prevent the accidental drop of the source outside the container. These preliminary safety works were performed on 19 April 2012. After assessing the situation and after several efforts the source was returned back to safe position inside the container on 23 April 2012. Finally, the reload of the source into the irradiator head was completed successfully on 25 April 2012.

A second technician (B) assisted technician A in the aforementioned activities

Both technicians used their personal dosimeters provided by their company.
However, at the beginning of their work in IRCL, GAEC provided technicians (A and B) with additional dosimeters (TLDs and APDs). The personal dose equivalent, Hp(10), values, according to the TLD readings, were 28.3 mSv for technician A and 12.1 mSv for technician B (for the whole operation period).

Moreover, from the second day of the work and on, given the importance of the situation and the possible exposure to the (narrow) primary beam, additional personal dosimeters (TLDs and APDs) were provided to the technician A, who operated close to the irradiator head. These dosimeters were placed on the chest, in order to record the doses in this region, which was most likely to be partially exposed to the narrow primary beam. The results, Hp(10), were 35.0 mSv.

Taking into account the national annual dose limits of the occupationally exposed workers, GAEC asked technician A to provide his official dose records, which showed that the recorded accumulated dose for 2011 was 1.22 mSv.

Following this, GAEC asked for a biological dosimetry analysis to be performed for both technicians at GAEC's collaborative laboratory.
The results of the biological dosimetry, which was based on the analysis of solid stained dicentric chromosomes in cultured peripheral blood lymphocytes, showed that:

• technician A received a whole body dose of no more than 197 mSv (95% upper confidence level) and no less than 30 mSv (95% lower confidence level), with a mean dose of 102 mSv.
• technician B received whole body dose in the range from 0 mSv to 60 mSv (95% confidence level).

The final rating for this event is Level 2.


The incident log for the above event can be read at the following link: IAEA News Channel.

Ionactive Comment

Unlike some reports on the IAEA events feed, we have quite a comprehensive write-up here. This does however still lead to a number of questions, queries and comments. First off, a 110 TBq radioactive Co-60 source is not trivial by any standards. A source such as this, totally unshielded would yield a dose rate of some 30 Sv/h at 1m and over 3000 Sv/h at 10cm. A source such as this heavily collimated would yield a gamma dose rate beam of several Sv/h which appears to be suggested in the write-up.

Detail such as ‘It was completed successfully on 19 April 2012 after overcoming a few technical difficulties' does not fill me with confidence. The report does not detail the nature of the irradiator but one would hope that a) there was a safe change methodology; b) there was a detailed set of procedures indicating how to change the sources over, and c) most importantly, a contingency plan for dealing with stuck sources etc.

The report is not totally clear, but I take ‘one of the technicians having to work within the region of the primary beam for a few seconds' to imply body irradiation (rather an extremity dose to fingers etc). This seems be suggested when looking at the assessed exposures (although there is no information provided for extremity exposure).

The idea of a contingency plan is that it is based on a detailed task analysis and risk assessment so that all reasonably foreseeable events are determined. Then, a mock up is used to test the source load / unload procedure with an inactive dummy. This is why the following words from the report give me cause for concern: ‘After assessing the situation and after several efforts the source was returned back to safe position inside the container on 23 April 2012'. This indicates that the ‘head scratching' occurred after the incident (contingency plan initiated??) and they then tried a number of options to solve the problem - all with a 110 TBq radioactive source close by.

It appears that some thought has been given to the dosimetry required. They appear to have recognised the serious nature of this incident and the fact that narrow radiation beams were involved (hence a single whole body dosimeter may not adequately reflect a true exposure). So additional dosimetry was provided. However, this smacks of dosimetry being treated as a ‘piece of safety equipment' - which it is certainly not!

Very bad practice, bad planning, little contingency, poor supervision: resulting in significant overexposure of two workers. Appalling!

20/5/2012 - Overexposure to Radiographer's Assistant

This is taken from the IAEA News Channel (Nuclear & Radiological Events)

Overexposure to Radiographer's Assistant

 

[16 April 2012, USA, posted 06 April 2012, INES = 2 (Final)]

On April 16, 2012, the licensee radiographer's assistant informed the licensee Radiation Safety Officer that his pocket dosimeter had gone off scale 10 days prior. The licensee sent the radiographer's permanent badge for processing and the result was a 250 mSv (25 rem) whole body dose reading. The State of Florida was informed of the dose on April 24, and has verified the dose. The State of Florida continues its investigation.


The incident log for the above event can be read at the following link: IAEA News Channel.

Ionactive Comment

Not a very detailed report, and not much to add really. Yet another case of bad practice and a significant overexposure. This is not the Nuclear Industry either, I am sure many in the media assume that these types of exposure come from working with nuclear plant. Far from it.

It is worrying that this is another example of bad practice from the US (or is it just that the US are monitoring bad practice, whilst others turn a blind eye or even have no idea what is going on?).

22/4/2012 - A quick despatch from Bahrain : Radiation, Interpreter and other stuff

A Typical Pic from Bahrain this evening

Radiation Training in Bahrain

First day of the three day radiation safety training course is complete. A nice set of delegates indeed. Whilst they all have a grasp of English (some a perfect grasp), I am running the entire course through an interpreter. I must admit to being a little anxious about this. My previous experience of using an interpreter was during a 5 day course to a number of Libyan delegates a couple of years ago. This was a tiresome experience since I had to say a few words, then the interpreter would do their bit, then I would continue, then they would do their stuff - and so on. The whole experience was exhausting.

On this occasion I have an excellent interpreter and system at my disposal. She sits in a sound proof booth at the back of the room - I am using a radio microphone. All the delegates are wearing headphones. She is then able to interpret what I am saying into Arabic in real time. I think that is quite amazing anyway, but to do that when the subject matter is quite technical is remarkable! As required I also wear headphones so that if the delegates want to ask me a question then they can do so in Arabic and it is converted directly into English. The whole system worked fantastically today and it has relaxed me somewhat.

Working in Bahrain - the risks?

My family were obviously a little worried about my work in Bahrain - especially whilst F1 was in the major news and the implication was that the total county was in chaos. I would never take excessive risks when working and went to Bahrain on the basis of reassurance from clients and other friends and contacts. What this trip has emphasised is the role the media plays in ‘creating an impression'.

As many of you will know, I have been quite critical of the media with respect to the reporting of the nuclear events in Japan (see other blog posts). Clearly the nuclear events are significant but the media appears to have an agenda to ramp up the nuclear issues way beyond their rightful place (when compared to the loss of life in the area from the natural events). This was most obvious on the anniversary of the earthquake and tsunami where the media seemed to be obsessed with the nuclear event at the expense of the natural disaster.

"Perception is reality" ?

A typical local street scene in Bahrain tonight

With respect to radiation issue I obviously have an advantage - I know my subject well and could look at the media with a critical eye. With respect to the political issues and disturbance in Bahrain I could do no such thing - I am not an expert in the area. It is therefore not surprising that I was a little concerned prior to the trip. The media pictures and reports quite simply implied that the whole county was ‘rioting'.

That is simply not the truth or fact. I of course cannot comment about the whole of Bahrain and I acknowledge that there is trouble in some areas. However, the media image that it is in chaos and totally in strife is total rubbish. In order to get some exercise I did a 3 mile walk this evening around the streets of my local area. I think I would rather do this in Bahrain than in my own home town in Reading (UK) - ‘perception is reality and all that'. I met some great folk tonight from all around the world. I feel comfortable, safe and most importantly very ‘welcome'.

Another little view of Bahrain this evening

Media - please do better - what is news and what is ‘views' ??

21/4/2012 - Radiation Safety Trip to Bahrain - security related (and other thoughts)

Up Up and away to the Gulf!

Has been some time since the last blog entry - to be fair I have more time available to tweet my thoughts so do check out the tweet messages on this website or on Twitter.

I am today off to Bahrain to present a three day Radiation Protection Officer (RPO) training course based on security systems (i.e. low energy x-ray security screening equipment, high energy cargo scanners employing linac technology and trace equipment). I will also be dealing with gamma and neutron radiation detection systems and presenting a talk on radioactive source threat (i.e. malicious use of radioactive sources). It is nice to be asked to run these courses overseas, and with respect to Bahrain, particularly so since they do not yet have their own specific radiation protection legislation.

Bahrain does not yet have its own Radiation Protection Legislation

We will be using the UK Ionising Radiation Regulations (IRR99) as a good model to following during the training. However, delivery of such a course overseas also forces me back to the International Atomic Energy Agency (IAEA) Safety Standards. Therefore we will be looking at the 1996 Basic Safety Standards (IAEA 115), but also considering the 2011 IAEA ‘Radiation Protection and Safety of Radiation Sources: International Basic Safety Standards' interim edition (General Safety Requirements Part 3, GSR Part 3). I actually wonder how many UK based Radiation Protection Advisers (RPA) have actually read the interim standard or even know it is now issued? I must be honest that I would probably not be rushing to read it unless I needed to.

It does however give you a clue as to what will be coming up when IRR99 is eventually revised (following a new EU Directive no doubt). There are not huge differences but they are present - for example the revised dose limit to the eye is now 20mSv / year (down from 150 mSv/year). In addition there is some considerable modernisation which, for example, accounts for the increasing use of x-ray in security applications. Whilst the current EURATOM Directive on radiation protection justifies the use (practice) of x-rays for screening passengers, the new IAEA GSR part 3 deals with this issue in much more detail: ‘Requirement 18: Human imaging using radiation for purposes other than medical diagnosis, medical treatment or biomedical research'. An important paragraph in this section of GSR Part 3 is the following:

3.66. Registrants and licensees shall ensure that all persons who are to undergo procedures with inspection imaging devices in which ionizing radiation is used are informed of the possibility of requesting the use of an alternative inspection technique that does not use ionizing radiation, where available.

The above wording makes it much more difficult to conduct covert screening where, for example, a portable car / lorry x-ray scanner is used for vehicles containing the driver and passengers. These units generally deliver a dose of radiation < 0.1micro Sv effective dose per scan. However, the words ‘where available' might be used in the justification process for such covert monitoring.

My trip to Bahrain

Up Up and away over Saudi

Unlike my last trip to Bahrain (January 2011) I cannot say I feel as comfortable as I should at this point - and that is not down to the flight either (whilst writing this I am currently 39,000 feet above Saudi Arabia). No, it's clearly down to the protests in Bahrain which have clearly increased (if I am to believe the western media) with the arrival of the F1 motorcade. On one level I could have done with the F1 being cancelled, if only because I think it would have been calmer.

That rather selfish thought should be binned anyway, if you like your F1 that I do not see why it should be made the focus of protest to make political points (since the world media is watching). Then again, if I was a protester and wanted to make a point - then what better opportunity is there to make it when everyone is watching? The simple fact that the world is watching means that the protester needs to decide what impression they want to leave. One impression might be a legitimate protest perhaps about human rights, jobs and political systems. On the other hand, throwing petrol bombs at foreign visitors (deliberately or by mistake) is not going to leave the right impression is it? I suppose some of my mutterings could also apply to the Bahrain police / security services - they have to be careful with the impression they also leave when the whole world is watching.

We shall see - I have no plans to see the F1 race on Sunday (I am working anyway), so I will just keep well away and hope for some peace and quiet in what was a fantastic country the last time I visited.

Does Ionising Radiation and Food Mix?

Ionising Radiation  - served on a plate

Oh, before I go, the obligatory radiation monitor / aviation food picture. This was taken at 39,000 feet (or could be 41,000 ft). The dose rate is lower than what I see when I frequently fly to Scotland (from Heathrow) since this was taken somewhere over the Gulf and therefore at a lower latitude. The second picture is taken from the washroom (!) - got a nice shot of absolutely ‘not a lot' below me.

More later.

Update 21:45 (Bahrain Time)

Well made it to the hotel so I thought I would just add a little extra afterthought (since the above was written on the flight to Bahrain). Whilst not judging anything in totality based on a few hours here, it is just what I was expecting. Drive from airport to hotel uneventful. Hotel very nice, staff great, met lots of interesting people from all over the world already. Its calm, quiet and still quite warm (about 21 degrees C at 2145 Bahrain time).

previous results
PAGE 4 OF 44
next results

About Our Blog

This is the company blog of Ionactive Consulting Limited, a Radiation Protection Adviser consultancy. Visit here often to read our views on radiation protection and related matters. You can contact our director and RPA directly at mark.ramsay@ionactive.co.uk

RSS Feed

Credentials

Twitter Updates

Follow Ionactive on twitter