/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 54 Assuming an average energy relea... [FREE SOLUTION] | 91Ó°ÊÓ

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Assuming an average energy release of \(200 \mathrm{MeV}\) per fission, calculate the number of fissions per second needed for a 500 MW reactor.

Short Answer

Expert verified
The reactor needs approximately \( 1.563 \times 10^{19} \) fissions per second.

Step by step solution

01

Understanding the Problem

A reactor with a power output of 500 MW (megawatts) releases energy as a result of nuclear fission. Each fission event releases 200 MeV (million electron volts). Our task is to calculate the number of fissions occurring per second in order to produce this power output.
02

Convert units of power from Megawatts to Megaelectron volts per second

1 watt is the rate of energy transfer equivalent to 1 joule per second. To convert megawatts to megaelectron volts per second, we use the conversion factor: 1 W = 1 J/s and 1 eV = 1.60218 x 10^{-19} J. Thus, 500 MW is 500 x 10^6 W or (500 x 10^6 J/s). Converting this to MeV/s we get (500 x 10^6 J/s) / (1.60218 x 10^{-19} J/eV) = (500 x 10^6 / 1.60218 x 10^{-13}) MeV/s.
03

Divide the power output by the energy per fission to find the number of fissions per second

Once we have the power in MeV/s, we can find the number of fissions per second by dividing by the energy released per fission. Using the formula: Number of fissions/second = Power (MeV/s) / Energy per fission (MeV). Substitute the values we have: Number of fissions/second = (500 x 10^6 / 1.60218 x 10^{-13}) MeV/s / 200 MeV.

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Key Concepts

These are the key concepts you need to understand to accurately answer the question.

Nuclear Reactor Energy Output
Understanding the energy output of a nuclear reactor is crucial when considering its ability to generate electricity. In the atomic nucleus of certain elements, such as uranium or plutonium, large amounts of energy are stored. This energy can be released through a process known as nuclear fission, where the nucleus splits into smaller parts, releasing energy in the form of heat. This heat is then used to produce steam, which drives turbines to generate electricity.

The power output of a reactor is typically measured in megawatts (MW), where one megawatt is equivalent to one million watts of power. This unit measures the rate at which the reactor produces energy. A reactor with a 500 MW capacity, for instance, is designed to deliver an energy flow of 500 million joules every second, continuously converting nuclear energy into electric power. By calculating the number of fissions per second, we can understand the number of individual reactions taking place to sustain this immense output.
MeV to Joules Conversion
The energy released in nuclear fission is typically expressed in million electron volts (MeV). An electron volt (eV) is the amount of kinetic energy gained by a single electron when it accelerates through an electric field potential difference of one volt. It's a convenient unit in nuclear physics, but for practical energy calculations, we need to convert MeV to joules (J), the standard unit of energy in the International System of Units (SI).

To convert MeV to joules, one must use the conversion factor: 1 eV = 1.60218 x 10^{-19} joules. Therefore, to convert energy from MeV to joules, we multiply the amount in MeV by this factor. For instance, 200 MeV of energy is equivalent to 200 x 10^6 x 1.60218 x 10^{-19} J, simplifying the math to understand the scale of energy being handled during nuclear reactions.
Power to Energy Per Second Calculation
The power generated by a reactor, or any energy source, is the rate at which it does work or produces energy. Power is different from total energy because it represents energy per unit time. The unit of power is the watt (W), which is derived as 1 joule per second (J/s).

When calculating the number of fissions required for a given power output, we follow the principle that power equals energy divided by time. This allows us to reverse-engineer the process to find how many individual fissions are needed per second to achieve a certain power level. By calculating the reactor's output in joules per second and knowing the energy released per fission in joules, one can divide the total power output by the energy per fission to arrive at the number of fissions required per second for a reactor to produce its intended power output.

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