Online Elemental Analysis pt 1

Season 2 of Yokogawa Debunks kicks off with Sean discussing a unique yet misunderstood technology, online elemental analysis with nuclear instruments. In this episode, our guest Stephan Nel from RTi Australia clarifies the common misconceptions about nuclear instruments and shares fascinating insights around safety and the principle of operation of online elemental analysers.  

Transcript

 [00:00:14.690] - Sean
This is a Yokogawa Australia and New Zealand podcast. Welcome to a new season of Yokogawa Debunks conversations with industry experts to demystify the misconceptions we hear in the process instrumentation and process automation space. I'm your host, Sean Cahill, and thank you for joining us today. Season one was a great success, and we thank all of our listeners and colleagues who have praised our efforts to discuss so many topics in our industry and given us new ideas and new thoughts on what they would like to hear about. I'd also like to remind you that if you enjoy the podcasts, please reach out via our email on debunks@yokogawa.com 

[00:00:52.370] - Sean 
Now we wanted to kick off season two with a special topic: the misconceptions surrounding online elemental analysis performed via a very unique yet misunderstood technology. So today we've invited Stephan Nel, who is an expert in this field at real time instruments, also known as RTI, who are a business partner to Yokogawa Australia and New Zealand. Stephan is an expert in neutron generators and safe radioactive isotopes used in online elemental analysis. And he's going to help us debunk a few of the misconceptions today. So good morning, Stephan. Pleasure to have you on board. 

[00:01:28.130] - Stephan 
Good morning, Sean. Thanks for the invitation to join this I think very important initiative undertaken by Yokogawa. 

[00:01:36.530] - Sean
Look, we're so pleased you can join us. And I'd like to start the conversation with a bit of an introduction if we can. So please can you tell us a little bit about yourself and your experience with online elemental analysis in the industries that you've been exposed to?

[00:01:50.510] - Stephan 
Sure. I started my career as a field service engineer for a company in South Africa about 30 years ago, 35 years ago, perhaps. And where I was exposed to commissioning and calibrating and installing some of these nuclear type instrumentation. My exposure has been in various industries like coal mining and coal processing and also power generation. And in addition to that, also cement production and limestone mining and mineral processing mineral mining and also food and packaging. With my instrumentation background and my master's degree in business administration, I understand some of the operational challenges from a technical and commercial aspect and as I mentioned, the journey has been long. It's been arduous, but I've gained a lot of experience throughout that's great. 

[00:02:44.750] - Sean 
That’s great and Look one of the things that we're looking forward today is delving into that industry expertise that you've got. And there's quite a few myths and misconceptions around these devices that we've got. 

 Now the first and probably the most common one, relates to the automatic reaction that end users display with the word nuclear. This word tends to be associated with nuclear energy and the infamous catastrophes at Chernobyl and Fukushima. So therefore, radioactive equipment it's considered by many as a little bit unsafe. So, when faced with this type of response how do you address the concerns? And what would you say to those technicians out there whose first reaction is to keep away from the radioactive material signage? 

[00:03:27.710] - Stephan 
Yeah, I think we first have to understand that both the Fukujima and the Chernobyl disasters were caused by the failure of secondary safety systems and It was on a much grander scale than we could ever expect to see on some of these operating sites where the technology is applied. When people do walk on sites and they see these radioactive protection signs or warning signs, they do tend to steer away, which in itself is not a bad thing. Now, at this point, I think the principle that I would want to point out is ALARA, which means As Low As Reasonably Achievable, and it doesn't matter how low the exposed radiation rates are. 

 [00:04:10.610] - Stephan 
The objective is to keep those rates Alara, by maximizing the distance, maximizing the shielding and minimizing the time of exposure. There is ever a requirement for personnel to spend some extended periods of time in close proximity to some of these areas. Now, if you do apply the principle of ALARA, the situation is deemed safe. 

 Probably over the last 20 to 25 years we've seen a rapid increase in the demand and application of these online instrumentation. Probably the most common ones are what they call neutron activation and gamma attenuation. 

[00:04:49.790] - Stephan 
In order to clearly understand radiation safety and address the concerns, we have to firstly understand what types of radiation we can expect and the terms associated with radiation. Firstly, Neutron radiations and neutrons are being stopped by materials that contain large amounts of hydrogen like concrete, polyethylene, or water. Second, is Beta radiation, which can be stopped by a thin layer of metal foil, cloth, or even plastics. Thirdly, we have Alpha radiation, which can easily be stopped by the outer layer of our skin and is not considered a biological threat. 

 [00:05:31.130] - Stephan 
Now, Alpha particles are contained within some of these isotopes that are used for online elemental analysis. The last is gamma and X ray. It could be stopped by dense materials such as concrete, lead, or steel. Now, Beta and Alpha radiation could cause more localized damage at cell level, whereas gamma is more referred to as whole body exposure. And this is what makes it more suitable for taking X rays of the whole human body. The unit of measurement for absorbed dose is referred to as rem and rem takes into account the energy absorbed and its biological effect on the body caused by each of the four types of radiation mentioned earlier. 

 [00:06:15.950] - Stephan 
Now, the following examples that I'm going to be providing of absorbed doses are based on international Basic safety standards for protection against ionizing radiation and for the safety of radiation sources, which was issued by the International Atomic Energy Agency and other world health organizations. These limits are also consistent with the limits published by the United States Nuclear Regulatory Commission and ARPANSA, which is the Australian Radiation Protection and Nuclear Safety Agency. 

 Here are just a couple of examples. If you were to fly across the Atlantic Ocean, you will be exposed to around 6 millirem. Going for a chest Xray about 10 millirem. 

 [00:06:59.810] - Stephan 
Living in a brick house, you are exposed to about 75 millirem per year. At an elevation of 1600 meters, you'll be exposed to 120 millirem per year. Public exposure limits are set at about 100 millirem per year, which is then deemed as a safe dose. And exposure by nuclear instrumentation on site is less than 20 millirem per year if you were to walk past the equipment hourly every day for a year. 

 So from this we could gather that being exposed to the instrumentation is significantly less than the public exposure limit at 100 millirem, which is then deemed safe. 

 [00:07:43.730] - Stephan 
The principle of ALARA is applied by medical radiographers on a daily basis by maximizing the distance from the source, maximizing the shielding and minimizing the time. 

 [00:07:55.970] - Sean 
Thanks, Stephan. Those are really valuable insights into some of the safety concerns, and you can see how they're sometimes blown out of all proportions and become that misconception that we just addressed. Now for end users in a number of industries who can overcome that initial hesitance and invest in the online analyzers, and they follow those strict regulations and recommendations you just mentioned. What is the main benefit that they can get from this technology? 

 [00:08:23.210] - Stephan 
That's quite an interesting question, Sean. We have to understand that due to the fact that it is a nuclear technology, it's non-intrusive, so it's not in contact with the material that it's analysing, which in itself does have the benefit of there's no real moving parts, you don't have to install wear liners for abrasive type materials. Another benefit is the fact that It actually does analyze all the material or at least 90% plus of the material that is exposed to the nuclear isotope or radioactive nuclide. So it is a very representative of what's happening on conveyor belts and within pipes where it's applied in a slurry application. 

 [00:09:17.090] - Stephan 
And as I mentioned before, it's a non-intrusive type measurement. The additional benefit is the fact that the data availability from this technology is on a minute-by-minute basis. So it's termed as real-time data where the normal latency associated with taking samples from conveyors or out of pipes, then preparing a sample and sending that to a laboratory for analysis and a couple of hours, and in some instances a couple of days later, the customer does have access to this data kind of lends itself to a reactive type of approach to controlling some processes within these plants, as opposed to having this data and information available in real time does enable the operators to react to process changes within the process quite quickly and make some Proactive control decisions in determining final product quality. 

 [00:10:24.470] - Sean 
So it's pretty much a set and forget instrument and not only set and forget instrument, but one which gives you a whole range of data on your process that most of the time you pretty much wouldn't have. So that's fantastic. Now, another myth around these devices comes from field technicians. This is something that's being reported back by some of our own people. Everyone understands radiation from a medical X ray point of view and you touched on that earlier and believe that the same principle is in use by nuclear instruments. 

 [00:10:54.230] - Sean 
Is this true or simply put, please demystify, how a nuclear device works for our audience? 

 [00:11:00.770] - Stephan 
Sure, Sean, there is obviously some truth in the principle, the difference being that when you go for an X ray, you're exposed to fairly high doses, but for a very short period of time, whereas the use of the technology on site is a continually emitting radiation, but at a much lower energy level. Using the isotopes Caesium 137 and in some instances, Cobalt 60, for the measurement of density within a pipe, you would normally have the nuclide on the one side of a pipe and a photomultiplier tube, or commonly known as a detector on the other side. 

 [00:11:43.550] - Stephan 
And as the material density inside the pipe increases and decreases, more or less of the initial signal transmitted by the nuclear isotope on one side is seen by the detector on the other side, which indicates an increase and a decrease in the density of the material. 

 Neutron activation or prompt gamma neutron activation is a bit more complex and makes use of the isotopes Americium-Beryllium, Californium 252, and also neutron generators. It works on the principle of fast-moving neutrons, which is being thermalized or slowed down through various materials within the actual Analyzer. 

 [00:12:24.170] - Stephan 
And in doing so, it actually imparts some energy inside that atom and that atom as it returns to its natural state, emits a gamma ray. That gamma ray is unique to that specific element in terms of its milli-electron-volt energy. Gathering all these energy levels of the various elements emitting the Gammas and spectrally analysing it can give you quantitative data in terms of how much of the element is actually existent within the burden of material that's being measured and combining that with a mass measurement input device, then you can provide some quantitative data, cumulative data, and also rolling average data, which enables the operators then to react in real time to some of these process changes in determining some of the final quality of the output of the final product. 

 [00:13:20.990] - Stephan 
This is where it's probably slightly different to normal medical techniques that is incorporated or used in the medical industry. Whereas, as I've mentioned before, it's a short burst of energy for a very limited period of time, whereas industrial systems are emitting radiation at very constant level for extended periods of time in order to introduce the reaction within the material to then provide that data. 

 That is the major difference between going for an X ray and utilizing this technology on site. 

 [00:13:58.790] - Sean 
Well, thank you, Stephan. I think that's really really helped with demystifying some of the misconceptions around the safety elements of this fantastic technology. Now, unfortunately, we've actually come to the end of today's episode, but I think we've seen that there are many misconceptions and myths here that we still need to address, as well as looking at the two main configurations of nuclear devices. So hopefully, Stephan, you'll be able to join us for another episode of Yokogawa Bunks. 

 [00:14:25.490] - Stephan 
Yes, I'm Sean would value the opportunity to do so and looking forward to the next one. 

 [00:14:31.910] - Sean 
And thank you very much for listening. And if you have any particular questions for Stephan or for us, please reach out via email at debunks@yokogawa.com or at Stephan.Nel@rtiaustralia.com 

 [00:14:47.150] - Sean 
And don't forget to like and share your favourite Debunks episode on your social media channels. So until next time, stay safe and remember YOKOGAWA DEBUNKS!