Radiation on an Aircraft

[Alan P]

I've flown all over the world on flights between 8 and 16 hours at least eight times a month for 15 years and a) I'm still here and b ) have had two kids so I'd guess the effects of radiation at airliner cruising altitudes is not particularly dangerous  We were warned about higher radiation levels near the North Pole but even that wasn't excessive.

 

I visited the Nagasaki atomic bomb museum a few years ago and was astonished to find out that background radiation levels were more or less back to normal within a couple of years. Obviously the city looks completely normal nowadays with normal levels of vegetation and no trace whatsoever of the atomic blast outside of the museum.

 

 

[JWM]

On 6/8/2021 at 11:22 AM, dov said:

Hallo

A question which is totally open and unsolved to me:

 

Radiation on an aircraft.

 

After a flight cycle, just for a civil airliner. Let say after 9 hours flight in 40 000 ft.

Is the high altitude radiation still there after landing or not?

Which amount of radiation is it?

 

More specific:

 

Which doses of radiation must an aircrew absorb?

What is the standard international?

The other question:

 

A military aircraft.

 

For example returning from war. As it was the 2nd Gulf War, returning Tornados.

If I am stenciling military aircraft, so I often have to handle radiation stencils. Mig-27, Intruder, Prowler etc.

Is this radiation stenciling for electro magnetic radiation? Which radiation is it? And which amount?

If we have an military aircraft in a museum, do we have still radiation on it?

Or is it totally safe?

The gun, when using uranium projectiles is also a hot part.

Does anybody have a clue about it?

 

Happy modelling

Hi

I am a nuclear physicist, so I can answer for some questions. The direct cosmic flux is of course decreasing when you go to surface, however some materials can be slightly activated by neutrons. For example after flight from Honolulu to Kraków we were able to detect some Au-198 on a wedding riing of my PhD student...

The cabin filters of airplanes are very interesting radioactive collectors - in low stratosphere there is much more so called cosmogenic nudionuclides, first of all Be-7. I was doing some research on them ...

Regards

J-W

 

[JWM]

3 hours ago, Alan P said:

I've flown all over the world on flights between 8 and 16 hours at least eight times a month for 15 years and a) I'm still here and b ) have had two kids so I'd guess the effects of radiation at airliner cruising altitudes is not particularly dangerous  We were warned about higher radiation levels near the North Pole but even that wasn't excessive.

 

I visited the Nagasaki atomic bomb museum a few years ago and was astonished to find out that background radiation levels were more or less back to normal within a couple of years. Obviously the city looks completely normal nowadays with normal levels of vegetation and no trace whatsoever of the atomic blast outside of the museum.

I confirm, that both Nagasaki and Hiroshima are not showing especially increased radiation background. One have to remember that in following years, basically till 1963 more than 500 nuclear explosions were done in open atmosphere (by US, USSR, UK, France and China). After that year only France - till 1976 and China - till 1980 conducted explosions in air ending with total 529 of them in 16 October 1980.  The total yield of all  explosions was equal to ca. 20 000 bombs like that dropped on Hiroshima! This was because of very high yield of thermonuclear weapons.  This made so called global fallout. The whole Earth is contaminated, for  example 4 t of plutonium is spread more or less evenly on the planet (the highest values on temperate northern zone close to 60 Bq/m2  (in means that on each 1 square meter in Europe you may expect 60 radioactive decays in a second coming from Plutonium) .  For Cs-137 it is now about 2000 Bq/m2,  The studying of such problems is what exactly I do in my work. For example with my PhD students we investigated bones of Antarctic penguin (found dead, we were not hunting in Antarctic!) and we had no problems with measurements of plutonium isotopes there... Similar levels we found in  bones of people from Poland - we analysed the knee or heap join bones obtained from people who underwent a join replacement surgery...

Regarding the doses to airliner pilots it was studied by my colleagues (but not by myself)  within a project devoted to this question. As far as I remember their results the annual dose obtained by pilots was on range of 6-8 mSv, the deck crew was getting similar.   It is still below maximum permissible level which is (for occupational exposure) equal to 50 ms /5 years and not more then 20 mSv in one year.  Typical citizen in my country gets about 2.7 mSv a year from all environmetal exposures, additional 1 mSv from averaged medical exposure. The main problem was that women (stewardess or pilot)  should be grounded immediately when they became pregnant and usually they do not do this...The symptoms of acute radioactive disease starts close to short time exposure of 500 mSv (or 0.5 Sv if you like) and the risk of 50%  death is with dose of 4 Sv. about 10 Sv is 100% sure death.  It is said, then memebers of general pubic can get each year additional 1 mSv above what they gets from background. 

 

The areas north of Fukushima and west from Chernobyl shows still high contamination with long lived radionuclides, in case of Fukushima by Cs-137, in Chernobyl it also Cs-137 but due to another details of accident more radioisotopes are present like:  Sr-90, plutonium, americium, curium.....(+long list of diminishing importance nuclides). 

 

Regards

J-W

 

[Alan P]

Fantastic information @JWM but if I may correct one thing, as soon as women notify pregnancy to the airline, they are immediately grounded. This is definitely the case in US/Europe (although other parts of the world may not necessarily do the same) as the risk is recognised.

[JWM]

2 minutes ago, Alan P said:

This is definitely the case in US/Europe (although other parts of the world may not necessarily do the same) as the risk is recognised.

I agree, this is how it should be done, but when they are grounded their salaries diminish rapidly (at least on some companies) - so there is economical pressure to delay with notification the company on pregnancy... 

[Alan P]

Just now, JWM said:

I agree, this is how it should be done, but when they are grounded their salaries diminish rapidly (at least on some companies) - so there is economical pressure to delay with notification the company on pregnancy... 

I see what you're saying now 👍 Though any salary reduction would be unlawful, I can imagine companies have creative ways to reduce the flying-related component of pay, or the loss of tax relief and so on.

[dov]

This is very interesting.

 

BTW I had to work on a nuclear test plants at university.

Radiation of the nuclear bombs all over the world as you mention did lots of harm to our environment.

Beside radioactive fall outs there is the thermic pollution.

Heat or in better words entropy.

The reaction of radiation for aircrews:

Does the tinted glass of a canopy have any protective measure in this case?

Like golden tints, green tints?

Prowler for instance?

F-35 too.

Do you have any idea about the radiation at US-test sides in the area around area 51?

 

Happy modelling

 

 

[JWM]

Hi,

I agree that global radioactive pollution is harmful, it is one of many factors of so called anthropopression. Studying it we are also thinking that due to that presence we can recognize the pathways in environment and that knowledge can be very useful in case of much high contamination, which can happen in future.  

The tinted glass protect mostly against UV radiation. Can reduce also low energy X-rays, but for neutrons, muons, gammas it is not enough for sure. 

 

The radiation on nuclear test sites can be locally very high. In mine opinion the most dangerous are places were so called "security test" were performed. They were dropping on nuclear bomb from high altitude without its nuclear explosion in aim to test if the shock of impact on ground can start nuclear explosion (result was that it cant). It was important to recognize due to practice of flying with atom bombs on board of airplanes what always has some risk of accident (the most know two were B52 accidents in  Palomares and Thule).  During impact from altitude the conventional explosives in ignition system usually blows up but not right in the one moment, so the plutonium is spread around and even years later it can be res-suspended to the air by winds. The inhalation of Pu metal or oxides compounds is the most harmful way how the Pu can go into living organism .  There us no very high gamma dose on such places so it is not very easy to recognize in site that this is the place contaminated with Pu. The Pu-239 emits gammas with low probability only traces of Pu-241 present in Pu-239 core as unwanted addition decayed with years into Am-241 which gives some direct gamma radiation (increasing with time).

The other high contaminated sites are places of shallow underground explosion. During "normal" nuclear explosion above ground the local fallout is much lower then in case of shallow (not the deep one) underground. It happens due to thermal convection in air which forming well known mushroom cloud transport most of fission and activation products to the level of 10-15 km. The majority of them are dispersed forming tiny aerosols, which can stay in air for days. This makes  local fallout less intense. In the shallow underground explosion much more fission and activation products stays on site. From one conference I remember a lecture  of join Russian-French research team about one underground nuclear explosion site in Yakutia, where an area of about 1 km2 is still sterilized by the radiation coming from radioactive debris.  I do not know by heart results from Nevada, but of course there must be places of higher contamination like they are on other test sites like Nova Zemlya, Semipalatynsk, Woomera in Australia, Murroa, Bikini....There is a lot of literature with detailed results. I remember one paper of my friend from Flagstaff (AZ), who was analyzing Pu isotopic ratios and Np-237 presence in sediments in lakes in US going from Nevada to Chicago. The given test site isotope signature is a bit different then averaged global fallout one. So the impact of Nevada test site was visible in those traces at almost whole distance to Great Lakes area...

Regards

J-W

  

[dov]

Oh yes.

I have a clue. The contaminated B-52 parts were than brought to the Savannah River Site in South Carolina.

Very good explanation.

The security test sites are hot areas.

I assume, that there are much more hot areas in the world.

No matter where.

On aircraft the dials are a problem. The new ones too?

Cosmic radiartion vanishes.

A/C carried nuclear bombs are no issue.

What about a/c using the cannon with uranium projectiles?

Like a barrel from A-10 or F-15 or F-16?

Happy modelling

[JWM]

Hi,

54 minutes ago, dov said:

On aircraft the dials are a problem. The new ones too?

In past it was Ra-226 used for stimulation of luminescence of dials. I;ve heard that at least in some case currently it is tritium, which is far more safety regarding doses (no gamma radiation, no emanation of radon...). But in modern airplanes the LCD screens cockpits dominates, isn't, 

 

 

54 minutes ago, dov said:

What about a/c using the cannon with uranium projectiles?

Like a barrel from A-10 or F-15 or F-16?

Regarding the AG 38 Avenger gun from A10 - This is a very deadly weapon for people (soldiers)  inside armored vehicle - but this is what one expect from weapon in fact, I am sorry to say... The heavier is the armor the more deadly it acts (more kinetic energy convert to heat, and then melted sprayed U rapidly react with oxygen from air releasing up to 7 times higher chemical energy than was its kinetic energy) 

I was involved in measurements in Serbia on sites where gun was used but we were able to find DU in environment only very close (below a meter) range to direct hit place.  In one shell it there is about one moll of uranium (~240 g), the average concentration of uranium in soil is close to 3 ppm (part per million), so in 1 ton of soil there is some 10 grams of U. Thus the single shell introduces additional uranium like that present in 24 t of soil.  AFAIR form official information during the war in former Yugoslavia some 30000 shells were used, in Gulf War (1991) it was 900 000 of them (~4 000 Iraqi armored vehicles were destroyed by this weapon)

Regards

J-W

 

Edited June 13, 2021 by JWM

[spruecutter96]

Here's a few aviation-related radiation stories:

 

1. When the F-104 Starfighter's engine has been running for a time, one part of its engine emits radiation (look for the radiation warning stencils, roughly half-way along the body). 

 

2. The US Navy's EA-6E Prowler electronic-warfare aircraft had gold-tinted canopy glass, to help protect the crews from the tail-mounted emissions pod's energy.

 

3. A fella who worked on the General Electric Company's project to put an AEW (Airborne Early Warning) radar on the RAF NImrod told me that, during some static, high power emission tests, he once glanced out of the window in time to see a nearby bird die in mid-air, as it flew into the stream of the Nimrod's radar. So, I would recommend staying well away from any AEW airframe that happens to be emitting on the ground. 

 

4. In the 1950's, the US air-force did a very serious study (and possibly built one example, I think) of an atomic-powered B-36 Peacemaker. They wanted an nuclear bomber that could stay in the air for weeks or months at a time. When the doubt was expressed that the atomic-core couldn't be made 100% safe (due to the required weight of shielding needed), it was actually suggested that any crew-members should only considered if they had already had all the kids that they were likely to create! In other words, the radiation-leakage was going to render them all sterile.... and, eventually, probably kill them too. Thankfully, they cancelled the programme before any of the aircraft actually got into service.   

 

5. A bit off-topic, this one..... When Radium became popular for illuminated clock-numbers (the 1930's, IIRC), the clock-factory staff used to regularly lick the bristles of their Radium-encrusted paint-brushes to create a good point on the brush. This practice was banned when a number of the employees started to lose parts of their jaws due to massive, localised doses of radiation. I'm not making this up.... there's a horrifying Youtube video on this subject - it's not easy viewing. 

 

Chris. 

 

PS: Something the makers of mobile-phones will NEVER, EVER admit to.... The signals that are emitted by the phones? They are "low-energy" microwave signals. Think about that one for a minute or two. 

Edited June 13, 2021 by spruecutter96
Correcting a typo.

[spruecutter96]

I've read that, following the Chernobyl disaster, the GLOBAL background radiation-count more than doubled. Makes you think, doesn't it?

 

Chris. 

[JWM]

32 minutes ago, spruecutter96 said:

I've read that, following the Chernobyl disaster, the GLOBAL background radiation-count more than doubled. Makes you think, doesn't it?

 

Chris. 

It is not not exactly like that. There is natural radiation background dose  in average at sea level equal to f 90 nSv/h  (1/3 from cosmic rays, the rest from natural radionuclides in soil and rocks). On some places on Earth it could be much higher due to presence of Th in local rocks. There is also global fallout, ie. result of bomb tests. And Chernobyl fallout in countries like Poland or other central Europe and doubled in average the global fallout levels (not the total dose). At maximum in Poland it was even several (~40 times) global fallout level in some areas on Silesia, where rain washed out radioactive cloud. But even there, the dose rate attributed to Chernobyl was not exceeding 30 nSv/y, so 1/3 of natural level. The real high contaminated areas are those at distance of let say 20-30 km west of Chernobyl. A high spot is close to Homel in Belarus (also due to rain - the rumors said that induced rain to protect Moscow area).  Larger or smaller higher activity spots are in several places in Europe even in Norway or Alps (Germany, Austria, northern Italy...) . This is map shows the  approximate pattern of Cs-137 in Europe

http://www.chornobyl.net/en/map-of-europe-contamination-with-cs-137-after-the-chornobyl-accident/

 

We mix up  here a bit the nuclear radiation with radio or microwaves radiation. Of course the microwaves from radars can heat up inner organs up to death of organism. Many accident like that happened  especially in armies, unfortunately. 

 

The NB36H was the variant of B36 flying with reactor. Ithe whole story is here https://en.wikipedia.org/wiki/Convair_NB-36H

The Soviets had similar modification of Tu-95. It is described here https://en.wikipedia.org/wiki/Tupolev_Tu-95LAL

Nice couple for modelling, isn't? 1/144 will be enough...

 

 

In march 2018 Russia officially claimed, that they have technology for nuclear engine jet for cruise-type missiles.  

 

Regards

J-W

 

[Jure Miljevic]

J-W, you beat me to it, but still ...

I believe in the NB-36H a working nuclear reactor had only been carried about and not used as a source of thrust. However, in Soviet Union a nuclear reactor had been used experimentally for that purpose. It had been installed in Tu-20 bomber's fuselage and supplied thrust for inner aircraft's engines. I do not know on what principle device worked, but both USA and USSR experimented with nuclear ram-jet engines. in the 70'. I think this principle is behind practically limitless range and endurance cruise missiles Putin announced in a speech few years ago.

Also, nuclear power has been used in to power satellites and space probes, either as simple RTG or radioisotope thermoelectric generator (Voyager I and II, Endurance, Perseverance ...) or proper nuclear reactor (RORSAT maritime reconnaissance satellites).

Cheers

Jure

[junglierating]

Is this a bad time to say that beta lights make excellent fishing floats 🤔

[dov]

Oh, thanks a lot.

 

This is a huge amount of pieces of knowledge. Just to get it in structure:

 

·        On the a/c today the dials are gone.

·        Some experimental use on a/c happened in the past.

·        One point is not clear: A gun barrel after firing uranium projectiles. Is this hot or not? Just on the a/c.

·        The matter on the F-104 is new for me. Does anybody know more?

·        The radar matter is in that intensity new to me.

 

One matter you may not know: The electro magnetic waves can harm any human being in a unbelievable way. It can cause abrupt epilepsy. Yes. I know it from my own body!

 

From Wiki

The NB-36H completed 47 test flights and 215 hours of flight time (during 89 of which the reactor was operated) between September 17, 1955, and March 1957 over New Mexico and Texas. The test flights revealed, that with the shielding used, the crew would not be endangered by radiation from the reactor, including with low-altitude flights, but that there was a risk of radioactive contamination in the event of an accident. In March 1961, shortly after he took office, President John F. Kennedy canceled the program. Tupolev Tu-95LAL was the sowjet project.

 

From Science Media Center

Russian Defense Minister Sergej Schoigu announced shortly before the end of 2019 that a new hypersonic glide missile called "Avangard" was ready for use. Russian President Vladimir Putin stressed that Avangard could reach almost any point on earth. With this first ready-to-use hypersonic gliding missile, which can reach speeds above Mach 20, i.e. twenty times the speed of sound, the Russian army has a system that can hardly stop the US missile defense. Avangard is an unpowered hypersonic glide missile that can be armed with conventional weapons, but also with nuclear weapons, including nuclear warheads. An ICBM brings the glider to the upper layers of the atmosphere and generates the necessary acceleration with which Avangard can reach these speeds. The glider then separates from the rocket and does not head for the target in a predictable trajectory. In this way Avangard can change course, even be led to a different goal if necessary. This maneuverability at such high speeds makes it nearly impossible for a missile defense system to prevent the attack. According to the Russian government, Avangard has already been shown to the US arms controllers and is not intended to contradict the provisions of the New START treaty (treaty for the reduction of strategic weapons).

 

Happy modelling

[spruecutter96]

On the subject of the depleted-uranium rounds fired by the A-10, I have read that the shells are only harmful to humans when they shatter or are burnt. In other words, if you know a tank has been hit by an A-10's gun, keep well away from it!

 

Chris. 

 

 

 

 

[bentwaters81tfw]

Ref the F-104, the J-79 engine contains certain metals (I forget which ones) and the NMUSAF have been removing engines from exhibits because the metals corrode and give off nasties. @Julien can probably give you a more comprehensive answer.

[Julien]

Ref the A-10 rounds yes the harmful effects are after they have hit the target and its gone through its pyrophoric stage.

 

Not sure about the F-104 engine, I know US phantoms had a gearbox in them containing a thorium alloy and this can be an issue. This was seen on the F-4J(UK) which was at manston as this had MOD warning on it. Not sure if these parts were removed before it was sold to the Phantom Preservation Group?

 

 

[JWM]

6 hours ago, dov said:

One point is not clear: A gun barrel after firing uranium projectiles. Is this hot or not? Just on the a/c.

The construction of projectile is that uranium rod has some 10 mm diamer and it is in aluminum tube and there are teflon rings to reduce friction on gun barrel after firing (30 mm caliber) . So I think no traces of U left in a barrel. Maybe if it is jammed only...It depends what exactly happened. 

Regards

J-W

[bentwaters81tfw]

Looking at my training round, it has a soft transparent nylon sleeve, and 3 lighter rings can be seen through it. This will be what makes it gas tight, and slightly larger diameter than the round itself.

[Julien]

10 hours ago, JWM said:

The construction of projectile is that uranium rod has some 10 mm diamer and it is in aluminum tube and there are teflon rings to reduce friction on gun barrel after firing (30 mm caliber) . So I think no traces of U left in a barrel. Maybe if it is jammed only...It depends what exactly happened. 

Regards

J-W

Yes this is correct for the A-10 round, the DU core is in an Aluminium jacket. 

DU does not flatten on impact but self sharpens almost the outer bits which come off ignite, its this bit you dont want to breath in. Hence why after the Gulf war servicemen were told to stay clear of tanks knocked out as this could still be present. 

 

Now these I would not want to fire!

[dov]

Hallo

 

This are very interesting facts, I had no idea of them!

 

Thorium Alloy  

 

From Wiki

 

These alloys commonly contain manganese and zinc, but there are other combinations known. Some common alloys are named HK31, HM21, HM31, HZ32, ZH42, ZH62; where the "H" indicates that the alloy contains thorium. Magnesium alloy names are often given by two letters following by two numbers. The two letters indicate the main elements present in the alloy where A = aluminum, Z = zinc, M = manganese, S = silicon, etc. the numbers tell percentage compositions of the two elements. So, AZ31 would indicate that there is 3% aluminum and 1% zinc in the alloy.

 

Magnesium-thorium alloys have been used in several military applications, particularly in missile construction. The most noted example of this is the ramjet components in the CIM-10 Bomarc missile and Lockheed D-21 drone, which implemented thoriated magnesium in their engine construction. This is due to thoriated magnesium alloys being lightweight, having high strength, and creep resistance up to 350 °C. But, these alloys are no longer used due to radiation concerns involving thorium's radioactivity. This has resulted in several missiles being removed from public display. Similarly, the structure of the Equipment and Retro-Rocket Modules of the Gemini spacecraft (the white-painted portions) were made of thoriated magnesium for their strength-to-weight ratio and thermal properties. These were not part of the inhabited cabin, though the radiator tubing, whose silicone coolant flowed through the cabin, was also made of the same material. All examples burned up in the atmosphere upon reentry.

Another concern for the thoriated magnesium alloys is the low melting point and rapid oxidation of the metal. This can result in dangerous flash fires during the production of the alloys. Additionally, thorium-free magnesium alloys have been developed that exhibit similar characteristics to mag-thoriated, causing currently used magnesium-thorium alloys to be cycled out of use.

This example from the gearbox I did not know.

 

Radiation in today’s flying

 

What about

 

·        Flying with fabric covered aircraft

·        Flying in high altitude with business jets and than frequently

·        Flying in gliders for mountain crossings

 

How much cosmic radiation can we expect by a flight with a Learjet from Europe to USA via NAT?

 

Here I have to add: In Austria we had two excellent pilots flying the whole operational PA-18 for the Luftpolizei.

Most of the flying was done in the alps. Approx.10000ft or higher. Both pilots died on cancer.

 

Happy modelling

[dov]

Here is something more about the J-79:

 

https://www.researchgate.net/publication/333132986_RADIATION_EXPOSURE_OF_MILITARY_PERSONNEL_DUE_TO_THORIATED_MAGNESIUM_ALLOYS_IN_JET_ENGINES

https://inis.iaea.org/search/search.aspx?orig_q=RN:40072320

https://inis.iaea.org/search/search.aspx?orig_q=RN:48030248

 

Happy modelling

[dov]

https://www.moody.af.mil/News/Article-Display/Article/210768/f-105-static-display-receives-new-fiberglass-parts/