What is a fusion boosted fission trigger

[Nikhil Shah]

Can anybody in non-technical terms explain me what is fusion boosted fission trigger?<BR>----------------------------------------- <A HREF="http://www.indiaexpress.com/news/techno ... 110-0.html" TARGET=_blank>http://www.indiaexpress.com/news/techno ... -0.html</A> <P>The Thermo-nuclear device that India tested at Pokhran in Rajasthan in May 1998 used a "fusion boosted fission trigger" and had a yield between 40 and 60 kilotons.<P>This yield level has been confirmed by measurement of the radioactivity in rock samples lifted from the site of the blast.<P>The two major radioactive elements that could be assayed in most of the samples were manganese-54 and scandium-46, says a published report of India's Bhabha Atomic Research Center.<P>Analysts say that it was the thermo-nuclear device that announced to the world India's state of the art nuclear capabilities. The fact that India successively exploded five nuclear devices in a controlled environment and then announced a moratoriam on further explosions indicated that further research can be done by the country through simulation.<P>The Indian scientists successfully eluded the spy satellites in conducting the tests and it had taken an announcement by the Indian Prime Minister, Mr. Atal Behari Vajpayee, for the world to come to know of the development.<P>Western nations slapped sanctions upon India immediately thereafter, but India's restraint in the period that followed has led to the lifting of most sanctions. India has come forward as a mature and responsible nuclear-power and has spelt out the draft doctrine of a minimal and effective nuclear deterrent.

[Sarma]

Nikhil, it is not a "FUSION boosted FISSION device", rather it is "FISSION boosted FUSION device". Fusion in the above refers to coming together of two Hydrogen molecules to form a single Helium molecule. But this reaction requires very high temperatures to take place. Such high temperatures are, for example, available in Sun. The primary reaction in Sun being the formation of a He molecule from two hydrogen molecules. But during this process, there is a destruction of mass of the minutest prorportions (protons, neutrons) which releases enormous amount of energy.<P>Thus, in a hydrogen bomb, two hydrogen molecules(Tritium) combine to form a He molecule releasing enormous amounts of energy. But as I said, this reaction to take place requires high temperatures. The purpose of the Fission first stage is to provide the same.<P>Hope this helps<BR>Sarma

[S Bajwa]

It simply means TWO ATOM BOMBS in single shell. The inner Nuke bomb goes off first and causes the outer Nuke bomb to go off (providing the right temperature for reaction to fuse two Hydrogen Molecules to one molecule of HE and thus releasing "NUKE" energy). <P>Fuse is to come together to form one molecule, fission is to split. (so molecules in first bomb split and in second bomb come together) <P>Sandeep Singh Bajwa

[Calvin]

A thermonuclear weapon has two parts:<BR>(a) Primary which is ignited first with conventional explosive<BR>(b) Secondary, which is ignited by teh Primary<P>The Secondary is usually a fusion device, with tritium and Lithium deuteride as fuel<P>The Primary is usually a simple fission device. This is the case because most nations find it easier to obtain weapons grade Pu or U than to process tritium. In India we have a combination of the reverse -- we have a better process for obtaining tritium and limited weapons grade Pu (around 400 kg).<P>Therefore, we have gone in for a Primary that uses some tritium, and reduces the amount for weapons grade Pu (or even enables the substitution of reactor grde Pu).<P>The design of the Primary is very similar to the "alarm clock" or "layer cake" design -- and is described in greater detail in the NWFAQ run by Carey Sublette.<P>The Primary in a fusion-boosted-fission trigger uses a fission device to create fusion, and then uses the fast neutrons from fusion to enhance the yield of the fission reaction itself. The advantage, obviously, is that you need less fission fuel.<P>This has been discussed in the past, most recently in the Sainis thread on Radiochemical analysis -- which should be in the archives -- if not, I have a copy somewhere that I can mail or post.

[Kumar]

Heavier isotopes of hydrogen (1 proton) such as deuterium (1 proton+1 neutron) and tritium (1 proton + 2 neutrons) are preferred because they reduce the number of collisions needed to make a helium nucleus (2 protons + 2 neutrons). This increases the probability of fusion dramatically. Beta decays may also be involved these reactions in converting a proton to a neutron and vice versa.

[shiv]

Here is the news item from today's deccan Herald<P> <A HREF="http://www.deccanherald.com/deccanheral ... atbits.htm" TARGET=_blank>http://www.deccanherald.com/deccanheral ... its.htm</A> <P>Data confirms Pokhran yield at 50 kt <P> NEW DELHI, Nov 10 (PTI)<P>Post-shot radioactivity measurements of rock samples extracted from Pokhran have confirmed that the yield of the<BR>thermonuclear device detonated by India in May last year was between 40 kilotons (KT) and 60 KT.<P>The measurement is close to figures earlier estimated by the Department of Atomic Energy (DAE) scientists on the basis of<BR>analysis of seismic signals recorded by them.<P>The post-shot results are based on radioactivity measurements of fission and activation products present in rock samples from<BR>the test site. They have been published in a report of the Bhabha Atomic Research Centre (Barc) in Mumbai.<P>The report said the thermonuclear device tested at Pokhran used a 'fusion boosted fission trigger.`<P>The two major radioactive elements that could be assayed in most of the samples were manganese-54 and scandium-46, it said.<P>Anyone know BARC's website url???<BR>

[Kumar]

Vishi,<P>That was deliberate. I remember Indian scientists saying that they achieved fusion and they could have increased the yield by simply having more tritium. So, this test was not exactly a full thermonuclear test, but a thermonuclear device was tested nevertheless. After the demise of CTBT there is strong likelihood that some country will start testing afresh. India should then conduct a megaton thermonuclear test to convince the doubting thomases.

[shiv]

Vishi<P>This has been discussed time and again here<P>The two main reasons are:<BR>1) Proximity of villages preventing a higher yield device being tested - even so house walls cracked<P>2)India's proposed nuclear force does not envisage city-busting megaton nukes

[Calvin]

Shiv: <P>Do you have any references for the "no megaton nukes" assertion?<P>What size nukes have they hinted at?