# What is Nuclear reactor: Definition and 75 Discussions

A nuclear reactor, formerly known as an atomic pile, is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid (water or gas), which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. As of early 2019, the IAEA reports there are 454 nuclear power reactors and 226 nuclear research reactors in operation around the world.

View More On Wikipedia.org
1. ### Equation for neutrons in a nuclear reactor

I am trying to solve a problem from Thorne and Blandford: Modern classical physics, chapter 3, problem 21: Neutron diffusion in nuclear reactor. I am struggling with how the equation, from which this should be calculated, should look like. I watched some videos where they did the derivation a...
2. ### Size Limitation of fuel Bundle in a nuclear reactor

What is the limitation of length of a fuel bundle in a nuclear reactor. Can we increase the length of bundle consequently reducing the number of bundles in a fuel channel?
3. ### Taishan nuclear reactor Xenon problem

French press reports indicate that the first of the two EPRs built at Taishan in Guangdong province has unusually high levels of radioactive noble gases in the primary cooling circuit, presumably as a result of defective fuel bundles...
4. ### Could a high / very high temperature nuclear reactor operate in Venus?

Hi. I'm just a curious person with high-school-level scientific knowledge. However, I was wondering if a specially-engineered Generation IV high or very high temperature (800-1,000ºC) nuclear reactor could work in Venus using the local atmosphere at 450ºC as "coolant", just like a "typical"...
5. ### Using a minimized nuclear reactor for further space travel

I have been thinking and I thought of a design that may, theoretically result in spacecraft being able to have a self sufficient energy source on board. Here’s my theory, if you have a minimized nuclear reactor (if building something like this is even possible given that the nuclear reaction...
6. ### Nuclear Chain Reaction Conditions

Hi all, For my studies I chose a course on scaling up and down of industrial processes (mostly focussed on the chemical industry), but for our project we (a group of students who knew almost nothing about nuclear reactors) chose to look if the approach (dimensional analysis) can be applied to...
7. ### Nuclear Reactor Analysis Problem 5.34

I'm aware that geometric buckling is equal to material buckling when k =1, any pointers on how to set up the boundary conditions for this problem?
8. ### What Is the Big Round Thing on Top of a Nuclear Reactor?

Here is a 3D model I made of a nuclear reactor and reactor core.
9. ### Heat transfer in a nuclear reactor and the electrical equivalent

To write the equation I took as the control volume the following block: and the equation I wrote are: $$6m_{f} c_{p_{f}} \frac {dT_{f}}{dt} = 6P - \frac 1 {R_1} (T_f - T_g) \text{ for the fuel}$$  m_{g} c_{p_g} \frac {dT_{g}}{dt} = \frac 1 {R_1} (T_f - T_g) - \frac 1 {R_2} (T_g - T_c)...
10. ### Proper simulation code for a Nuclear Reactor core

Hi, I want to make a simple nuclear reactor core simulation to calculate the thermal power production. Is there any open source code with interface (or not) that you recommend to use? The core have cylindrical shape with Uranium( up to 90% enriched) molybdenum fuel,Beryllium reflector and one...
11. ### About the heat carrier in a nuclear reactor

Hello: I have small question , as I read about the ATF research in the news ,a question present it self , why no one does any research on heat carrier in nuclear reactor that can absorb nuclear radiation and change it to infra red radiation ? Best H
12. ### Calculating US Nuclear Reactor Fuel Supply

Homework Statement i have a little confusion with this problem the problem is asking me to calculate "how long could you fuel the 99 current reactors in the US?" Homework Equations The problem is asking for an evaluation of fuel energy value in comparison to demand edit:(i forgot to add that i...
13. ### Smallest Possible Nuclear Reactor?

What's the smallest nuclear reactor possible in terms of size and/or weight? What kind of power output could it achieve?
14. D

### Nuclear Reactor Rod Replacement Time

If an enemy had a secret nuclear reactor and they were retrieving the rods, or whatever it is that they retrieve to make secret nuclear bombs, how much time (how fast) would it take for them to retrieve their needed material? Would just a part of the reactor be shut down, and if so, what...
15. ### BWR Fuel Assembly Question -- Why do BWRs have shrouds?

Hey all, I was wondering if anyone could help me with a basic BWR question. Why do BWRs have shrouds? From what I've been able to find, this is a for "uniform cooling" but that's about it. My guess is that there are some thermal hydraulic benefits around maintaining nucleate boiling. Is...
16. ### What is the size of the nuclear reactor part of a nuclear power plant

Good morning at all, I have to do one research of the transport of large nuclear reactors, and I need to have an idea of which is the DIAMETER, HEIGHT and WEIGHT of the reactor I think that there are a lot of different dimension, but i want to know only approximately, because i don't have...
17. ### PWR Refueling Systems and Procedures

Hey all, I was wondering if anyone can help me out with understanding the PWR refueling process? I'm an undergrad getting introduced to these systems and was hoping there was someone in the industry that might have some insight into the details of this. In regard to the removal of the old...
18. K

### B Why uranium dioxide is used in nuclear reactors?

In Wikipedia I read that Uranium-235 is a nuclear is fuel in fission reactors, also that Uranium-235 is split (fission) and energy is revealed. But in some images showing how nuclear reactors work, they show Uranium dioxide as nuclear fuel elements. In Wikipedia, it's written that the oxides...
19. ### Are there any books about how to teach nuclear reactor physics?

Hello ,every one . I am a reactor physics　teacher . I want to find some books or papers about how to teaching reactor physics． if you know it ,please tell me. Thank you very much.
20. ### A How can quantum mechanics contribute in a Nuclear reactor

Hi, does treating neutrons as waves make any difference when it comes to micro cross sections ? , does quantum mechanics help more than classical mechanics in nuclear reactor physics ? Noticing that I am a nuclear engineering student
21. ### Engineering Mech engineering work in nuclear reactors

Hi all, I would like to know what's the kind of work a mechanical engineer has to perform when being part of the team encharged of building a fusion or a generic nuclear reactor. I find many areas in mechanical engineering attractive, but I believe that fusion reactors have great potential in...
22. ### Service Limits of a Nuclear Reactor

Nuclear reactors are licensed with a fixed service life in all countries. This is despite the fact that reactors have widely varying ages (some plants have taken decades to complete), varying use cycles (not all plants run at 90%+ capacity factor, some are even mothballed), and undergo power...
23. ### Coping with Nuclear Reactor Leakage: Lessons from Chernobyl and Fukushima

how do we cope with leakage of nuclear reactors as happened at Chernobyl and Fukushima plan
24. ### Nuclear Reactor Simple 1D Method of Characteristics Solver

Homework Statement Hi all, attempting to make a Method of Characteristics solver in Matlab. I'm particularly hoping that there are some computational nuclear engineering guys about who might have a bit of experience programming a simple version of one of these. I'm trying to create the solver...
25. ### Production of Co-59 in nuclear reactor.

Hi, As far as i know, when Co-59 is bombarded with neutron inside the reactor core then Co-60 is produced. What i want to know that what is the origin of the Co-59. Is it one of the products of nuclear fission? if it is so, can you show me the reaction of it. Or is it already exist in the...
26. ### How many barns at least for a commercial nuclear reactor?

The conventional commercial fission reactors use uranium-235 as fuel. Its cross section of (n, fission) reaction at thermal neutron is about 585 barns. My question is: Is there a known threshold of the cross section that makes a nuclear reaction not sustainable if the minimal cross section is...
27. ### Oklo-phenomenon - is this a Natural nuclear reactor?

I read a very interesting article about this u235 deposit found in Africa. Everything I have read about it suggest that some of the components needed for this to naturally occur can not exist without human intervention. The water involved in the nuclear reaction must be extremely pure. Even a...
28. ### Approximate mass of special alloys in a nuclear reactor?

Approximately, what is the total mass of these materials that is contained in a "typical" Gen III or III+ PWR (e.g., EPR, AP1000...)? 1/ Zr alloy (fuel cladding and other assembly components)? 2/ Ag-In-Cd alloy (control rods)? 3/ Gd (burnable neutron absorber)? 4/ Ni-based alloys? 5/ Stainless...
29. ### Why Is Krypton the Product in This Nuclear Reaction?

Can someone please explain to me why the answer to the following question is Krypton? A step by step solution would be ideal please! (b)The following reaction occurs in a nuclear reactor: 235U+01n →141Ba+X+301n+202.5MeV (i) Identify the element X. Many thanks! (Question is Q12 b part i...
30. ### PAX Nuclear Reactor Simulator Question

Hi to all, I am currently a student studying chemistry in high-school. My teacher has a program which he runs on very old laptops called the PAX Nuclear Reactor Simulator. I have a bit of experience writing code in C and Java. My teacher has mentioned that the school may trash the laptops which...
31. ### Looking for a Nuclear Reactor Text on Thermal Hydraulics?

Anybody know of a good nuclear reactor engineering text? I'm specifically looking for something involving thermal hydraulics of reactors, something along the lines of nuclear heat transport by el wakil
32. ### How Does Thermodynamics Apply in Nuclear Reactors?

hello all. I need some references and problems with soloution of nuclear reactor thermodynamic for practicing and learning better. like presurizer.and exc.
33. ### Understanding Nuclear Reactors: Exploring the Basics and Beyond

i know few things about nuclear reactors .i have a lot of doubts.i want to know everything completely such as 1.how control rods absorb neutrons? 2.how do scientists know what's happening inside an atom? and so on.... " can anyone tell me the complete details about nuclear reactors ? "...
34. ### Exploring the Possibilities of Killing an Unshielded Nuclear Reactor

I think about an interesting question - How many people can kill unshielded nuclear reactor in one second? Some averages, estimates ... Do you have any idea? And why? On what is it dependent?Thanks.
35. ### Nuclear reactor neutron absorber

Hi could you please explain me what happens with the atomic structure and overall material structure of neutron absorber rods used in fission reactors? As I imagine when they are used they absorb the neutrons that keep the chain reaction going so to stop the chain reaction hence shut the...
36. ### Control of coolant temperature in a nuclear reactor

I am trying to build a model of CANDU reactor core using a software called DYMOLA.For this purpose,I am trying to figure out a mathematical relation between coolant temperature and Power developed in a reactor.I have the following questions: 1.What is the effect of increasing the neutron...
37. ### Thermal hydraulic design of nuclear reactor core

By a simple procedure , what should I do when I'm going through the thermal hydraulic design of nuclear reactor core...? .. I put initial guesses for the core dimensions ( fuel , clad , gap , length) initial guess for the fuel element pitch desired power ... I've found q'' critical heat flux...
38. ### Introduction of nuclear reactor physics summer 2012

Hello I am looking to introduction of nuclear reactor physics course in the summer 2012 can u help me to find this course in any universities ?
39. ### Could a major solar flare knock out nuclear reactor safety?

I live in AZ so besides the "bubla" or whatever that stupid name is for a huge wall of dust we get that's crazy huge is about as bad as our weather gets. Basically Solar Flairs are the biggest threat to me and my dog, so its my the natural disaster of choice when thinking about different...
40. ### Do 2 Kilowatt Nuclear Reactor Still Exist

i was told that the smallest nuclear reactor power station is 2 Kilowatts and they take up about half a city block? is that correct? can they be built? Have A Nice Day!
41. ### Basic steps in modeling a nuclear reactor

I am trying to make simulation of severe accidents in advanced nuclear reactors. Can anybody advice me in how to write the input deck? Is there any training materials about that? Please, share your experience in simulationg nuclear reactors, problems you faced, etc.
42. ### How radioactive is nuclear reactor waste?

I want to know how much radioactivity in Becquerels is produced by a typical light water reactor in one year of operation. I don't know how one would go about estimating this number. I found one reference that said 27 tons of spent fuel are generated by a typical reactor per year. But I...
43. ### Why can’t decay heat be harnessed to safely shutdown a nuclear reactor?

Why can’t decay heat be harnessed and used as an energy source to safely power down/cool a nuclear reactor? I have been wondering about this since the reactor incidents in Japan as it appears a tremendous amount off energy must still be dissapated after the shutdown of a nuclear reactor in...
44. ### Nuclear Reactor In Ga. Shuts Down Abruptly

http://www.cbsatlanta.com/news/27633540/detail.html?utm_source=twitterfeed&utm_medium=twitter Does anybody have any further information on current status of this reactor in GA?
45. ### Why does a control rod work in a nuclear reactor?

Hello. I know that control rods in reactors work by absorbing neutrons that would otherwise be used to collide with say, Uranium, to cause fission. But here is the part I do not understand: As far as I understand, a Uranium atom fissions because it absorbs a neutron causing it to become...
46. ### Why Does A Nuclear Reactor Need A Body Of Water For Cooling?

Homework Statement Why Does A Nuclear Reactor Need A Body Of Water For Cooling? If steam is needed to run the generator turbine, why not send the water/steam exiting the turbine back into the reactor for additional heating without cooling the water/steam first? Homework Equations don't...
47. ### Nobody can solve my Nuclear Reactor Physics Question? me

nobody can solve my Nuclear Reactor Physics Question? please help me! In the centre of the core of a 1000 MWe BWR, the observed fission rate is 1.7×1012 cm-3 s-1 and the observed temperature of the fuel is 800 oC. What will be the fission rate at the same location if the temperature is raised...
48. ### Nuclear Reactor Physics Qestions me

Why don't you answer my Nuclear Reactor Physics Qestions? ...Please Help me [/B]1 ) Dry air at normal temperature and pressure has a mass density of 0.0012 g/cm3 with a mass fraction of oxygen of 0.23. What is the atom density of 18O? 2) In the centre of the core of a 1000 MWe BWR, the...
49. ### What is the major problem in developing SCWR's nuclear reactor?

What is the major problem in developing SCWR's nuclear reactor?
50. ### Calculating Fission Cross-Sections for Nuclear Reactor Fuel Designs

A utility is considering changing its fuel vendor and resulting fuel assembly design. The current fuel in the reactor is standard Westinghouse 17x17 fuel with a fuel rod pitch of 1.215cm fuel rod OD of 0.916cm. The clad thickness is 0.055cm. The new fuel design has a fuel rod pitch of...