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Performed a partial rewrite. Since decay heat is a very significant issue for nuclear reactor safety, I will probably be revisiting this article, as well as others that should know about decay heat.-- Burzum 07:09, 31 December 2005 (UTC)
Good! I shall read with interest (though I'm no great expert in this area). Just to warn you that the last 'Nuclear Technology' topic I contributed to, got a 'too technical' tag slapped on it Bob aka Linuxlad 16:44, 31 December 2005 (UTC)
Edit request: "This results in 13 MeV" --> "This results in 23 MeV"
I changed the definition of T_subscript_S to the correct definition as stated in reference [3]. The equation is number (3) of reference [3]. 68.35.150.245 ( talk) 02:13, 9 January 2011 (UTC) Mike McNaughton, mcnaught@unm.edu
Decay heat = Decay energy. May be change article title on “residual heat” (delayed heat; afterheat; shutdown heat)? Especially article about it. Hullernuc ( talk) 14:49, 23 March 2011 (UTC)
I'd say no. I recently toured Callaway Nuclear plant, and they talked of "decay heat", not residual heat. "Residual heat" also implys that no further heat is being produced by nuclear reaction, which is not what is being discussed on this page. Brad ( talk) 16:48, 30 September 2013 (UTC)
In the current version, the approximation for the decay heat is suggested:
Where is the decay power, is the reactor power before shutdown, is the time since reactor start and is the time of reactor shutdown measured from the time of startup (in seconds).
The last statement, in the parenthesis, about unit of measurement, is not supported by the PDF [3] cited. The cite [3] now refers to http://www.nuceng.ca/papers/decayhe1b.pdf ; there, the text just after the formula reads:
where P is the decay power, P0 is the nominal reactor power, τ is the time since reactor startup and τs is the time of reactor shutdown measured from the time of startup. The above expressions are valid for times between 10 seconds and 100 days (8.6 x 108 seconds) after shutdown.
The units of time are not specified there; so, the right hand side of the equation has dimension "time power minus one fifth". The left hand side of the expression is dimensionless. Therefore, the formulas (1),(2),(3) in [3] are just wrong.
However, if one looks for any indication to the units of measurement, trying to give some meaning to the formulas (1)-(5), then one should look to the text after equation (5) that refers to one specific case ( τs= 10 years ) confirming that τs and τ are dimensional quantities.
If the nuclear engineers cannot perform even the trivial dimensional analysis,
then we should not wonder that the reactors do explode.
dima (
talk) 08:29, 4 April 2011 (UTC)
Please add calculation method for determining the heat of radioactive decay in Watts per kg from half life and decay energy (MeV) of any radioactive isotope. Mollwollfumble ( talk) 18:14, 3 August 2012 (UTC)
This article is rated Start-class on Wikipedia's
content assessment scale. It is of interest to the following WikiProjects: | |||||||||||
|
Performed a partial rewrite. Since decay heat is a very significant issue for nuclear reactor safety, I will probably be revisiting this article, as well as others that should know about decay heat.-- Burzum 07:09, 31 December 2005 (UTC)
Good! I shall read with interest (though I'm no great expert in this area). Just to warn you that the last 'Nuclear Technology' topic I contributed to, got a 'too technical' tag slapped on it Bob aka Linuxlad 16:44, 31 December 2005 (UTC)
Edit request: "This results in 13 MeV" --> "This results in 23 MeV"
I changed the definition of T_subscript_S to the correct definition as stated in reference [3]. The equation is number (3) of reference [3]. 68.35.150.245 ( talk) 02:13, 9 January 2011 (UTC) Mike McNaughton, mcnaught@unm.edu
Decay heat = Decay energy. May be change article title on “residual heat” (delayed heat; afterheat; shutdown heat)? Especially article about it. Hullernuc ( talk) 14:49, 23 March 2011 (UTC)
I'd say no. I recently toured Callaway Nuclear plant, and they talked of "decay heat", not residual heat. "Residual heat" also implys that no further heat is being produced by nuclear reaction, which is not what is being discussed on this page. Brad ( talk) 16:48, 30 September 2013 (UTC)
In the current version, the approximation for the decay heat is suggested:
Where is the decay power, is the reactor power before shutdown, is the time since reactor start and is the time of reactor shutdown measured from the time of startup (in seconds).
The last statement, in the parenthesis, about unit of measurement, is not supported by the PDF [3] cited. The cite [3] now refers to http://www.nuceng.ca/papers/decayhe1b.pdf ; there, the text just after the formula reads:
where P is the decay power, P0 is the nominal reactor power, τ is the time since reactor startup and τs is the time of reactor shutdown measured from the time of startup. The above expressions are valid for times between 10 seconds and 100 days (8.6 x 108 seconds) after shutdown.
The units of time are not specified there; so, the right hand side of the equation has dimension "time power minus one fifth". The left hand side of the expression is dimensionless. Therefore, the formulas (1),(2),(3) in [3] are just wrong.
However, if one looks for any indication to the units of measurement, trying to give some meaning to the formulas (1)-(5), then one should look to the text after equation (5) that refers to one specific case ( τs= 10 years ) confirming that τs and τ are dimensional quantities.
If the nuclear engineers cannot perform even the trivial dimensional analysis,
then we should not wonder that the reactors do explode.
dima (
talk) 08:29, 4 April 2011 (UTC)
Please add calculation method for determining the heat of radioactive decay in Watts per kg from half life and decay energy (MeV) of any radioactive isotope. Mollwollfumble ( talk) 18:14, 3 August 2012 (UTC)