. Incluso cuando está apagado tras un periodo de uso normal,...

. Incluso cuando está apagado tras un periodo de uso normal, un gran reactor nuclear comercial transfiere energía térmica a una tasa de 150 MW por el decaimiento radiactivo de productos de fisión. Esta transferencia de calor provoca un rápido aumento de la temperatura si el sistema de refrigeración cae ( 1 vatios $=1$ julio/segundo $01 \mathrm{~W}=1 \mathrm{~J} / \mathrm{s} y$ $1 \mathrm{MW}=1$ megavatios). (a) Calcule la tasa de aumento de la temperatura en grados Celsius por segundo $\left({ }^{\circ} \mathrm{C} / \mathrm{s}\right)$ si la masa del núcleo del reactor es $1,60 \times 10^5 \mathrm{~kg}$ y tiene un calor específico promedio de $0,3349 \mathrm{~kJ} / \mathrm{kg} \cdot{ }^{\circ} \mathrm{C}$. (b) ¿Cuánto tiempo se necesita para obtener un aumento de temperatura de $2.000^{\circ} \mathrm{C}$, lo que podría provocar la fusión de algunos metales que contienen materiales radiactivos? (La tasa inicial de aumento de la temperatura sería mayor que la calculada aquí porque la transferencia de calor se concentra en una masa más pequeña. Sin embargo, más tarde, el aumento de la temperatura se ralentizaría porque el recipiente de contención de acero de $500.000 \mathrm{~kg}$ también comenzaría a calentarse).

Key Concepts

Thermal Runaway

Thermal runaway is a condition in which an increase in temperature leads to conditions that cause further temperature increases, potentially leading to a self-accelerating process. This phenomenon is especially critical in nuclear reactor safety, where a failure in the cooling system can result in rapid and uncontrolled temperature escalations.

Energy Transfer and Power

Energy transfer in the context of thermal systems involves the conversion of energy from one form to another, such as from nuclear decay to heat. Power, defined as energy per unit time, quantifies the rate at which energy is delivered to the system, which is crucial for determining how quickly the temperature increases.

Heat Balance Equation

The heat balance equation relates the energy added to a system to the temperature change experienced by that system. It typically takes the form Q = mc?T, where Q is the energy added, m is the mass of the substance, c is the specific heat capacity, and ?T is the temperature change. This equation is fundamental in assessing the thermal response of materials under energy input.

Specific Heat Capacity

Specific heat capacity is a material property that indicates the amount of energy required to raise the temperature of one kilogram of the substance by one degree Celsius. This concept is essential in calculating temperature changes when a known amount of thermal energy is added to a given mass.

Decay Heat

Decay heat refers to the thermal energy produced by the radioactive decay of fission products after a nuclear reactor has been shut down. Even when the reactor is off, these decaying isotopes continue to release energy, which must be managed to prevent overheating and maintain reactor safety.

Transcript

Please give Ace some feedback