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BONUS for Puerto Rico

Nuclear Makes History in Latin America

Completed in 1964, the BONUS reactor was the eighth nuclear power plant constructed in the world and the first in Latin America. BONUS was a new kind of nuclear power plant built to investigate a concept called “integral boiling-superheating.” This concept was a technique to heat steam beyond normal temperatures to generate electricity. In fact, that’s where the name “BONUS” comes from — the BOiling NUclear Superheater reactor.

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BONUS for Puerto Rico

Nuclear Makes History in Latin America

Completed in 1964, the BONUS reactor was the eighth nuclear power plant constructed in the world and the first in Latin America. BONUS was a new kind of nuclear power plant built to investigate a concept called “integral boiling-superheating.” This concept was a technique to heat steam beyond normal temperatures to generate electricity. In fact, that’s where the name “BONUS” comes from — the BOiling NUclear Superheater reactor.

HOME

BONUS for Puerto Rico

Nuclear Makes History in Latin America

Completed in 1964, the BONUS reactor was the eighth nuclear power plant constructed in the world and the first in Latin America. BONUS was a new kind of nuclear power plant built to investigate a concept called “integral boiling-superheating.” This concept was a technique to heat steam beyond normal temperatures to generate electricity. In fact, that’s where the name “BONUS” comes from — the BOiling NUclear Superheater reactor.

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From Atoms to Electricity

Powering our World with Nuclear Science

Conventional power plants burn fuel such as coal, oil, or natural gas, to produce electricity — but not nuclear power plants. Instead, nuclear plants like BONUS harness the heat produced during nuclear fission, a process where atoms split and release energy. Fission takes place inside a reactor and generates heat just as coal generates heat in a boiler.

Nuclear reactors use uranium for fuel. The uranium is processed into small ceramic pellets and stacked together into sealed metal tubes called fuel rods. Typically, more than 200 of these rods are bundled together to form a fuel assembly. A reactor core is typically made up of a couple hundred assemblies, depending on power level.

Inside the reactor vessel, the fuel rods are immersed in water, which acts as both a coolant and moderator. The moderator helps slow down the neutrons produced by fission to sustain the chain reaction. Control rods are inserted into the reactor core to reduce the reaction rate or withdrawn to increase it. The heat created by fission turns the water into steam, which spins a turbine to produce carbon-free electricity.

From Atoms to Electricity

Powering our World with Nuclear Science

Conventional power plants burn fuel such as coal, oil, or natural gas, to produce electricity — but not nuclear power plants. Instead, nuclear plants like BONUS harness the heat produced during nuclear fission, a process where atoms split and release energy. Fission takes place inside a reactor and generates heat just as coal generates heat in a boiler.

Nuclear reactors use uranium for fuel. The uranium is processed into small ceramic pellets and stacked together into sealed metal tubes called fuel rods. Typically, more than 200 of these rods are bundled together to form a fuel assembly. A reactor core is typically made up of a couple hundred assemblies, depending on power level.

Inside the reactor vessel, the fuel rods are immersed in water, which acts as both a coolant and moderator. The moderator helps slow down the neutrons produced by fission to sustain the chain reaction. Control rods are inserted into the reactor core to reduce the reaction rate or withdrawn to increase it. The heat created by fission turns the water into steam, which spins a turbine to produce carbon-free electricity.

From Atoms to Electricity

Powering our World with Nuclear Science

Conventional power plants burn fuel such as coal, oil, or natural gas, to produce electricity — but not nuclear power plants. Instead, nuclear plants like BONUS harness the heat produced during nuclear fission, a process where atoms split and release energy. Fission takes place inside a reactor and generates heat just as coal generates heat in a boiler.

Nuclear reactors use uranium for fuel. The uranium is processed into small ceramic pellets and stacked together into sealed metal tubes called fuel rods. Typically, more than 200 of these rods are bundled together to form a fuel assembly. A reactor core is typically made up of a couple hundred assemblies, depending on power level.

Inside the reactor vessel, the fuel rods are immersed in water, which acts as both a coolant and moderator. The moderator helps slow down the neutrons produced by fission to sustain the chain reaction. Control rods are inserted into the reactor core to reduce the reaction rate or withdrawn to increase it. The heat created by fission turns the water into steam, which spins a turbine to produce carbon-free electricity.
A New Kind of Reactor

Reactor Technology Puts Theory to the Test

Today, the primary types of nuclear power plants in the United States are boiling water reactors and pressurized water reactors. BONUS was a new type of boiling water reactor power plant.

The main difference between the BONUS reactor and other boiling water reactors is the amount of heat applied to the steam before it drives the turbine generator. Scientists in the 1950s and ‘60s wanted to try superheating steam beyond normal temperatures. It was thought this could increase efficiency and produce more electricity
than a normal nuclear power plant. BONUS was built to test this theory.

An Experimental Powerhouse

Superheated Steam Drives the Turbines at BONUS

Unlike other boiling water reactors, the BONUS reactor made steam in the center of the reactor core and then heated it in four surrounding “superheaters.” This superheated steam then drove a turbine generator to produce electricity. While water boils to steam at 212 F (100 C), BONUS was able to heat steam to 900 F (482 C) . This temperature is about 350 F (176 C) greater than a normal boiling water reactor. BONUS was able to produce up to 50 megawatts (MW) of heat — enough to power up to 200,000 homes!

Another unique part of the BONUS facility is the 190-foot diameter steel containment building, different from a typical nuclear power plant. The design is based on the “total

containment principle”: the steel dome contains the reactor as well as the turbine generator, electrical equipment, and reactor control room. In other words, all parts of the plant are totally contained within the dome.

On April 13, 1964, the reactor achieved “criticality” — a sustained nuclear chain reaction. This was the first time nuclear electricity was produced in Latin America. When it was operating, all the electricity produced at BONUS was provided to area power stations and used by local residents.

A New Kind of Reactor

Reactor Technology Puts Theory to the Test

Today, the primary types of nuclear power plants in the United States are boiling water reactors and pressurized water reactors. BONUS was a new type of boiling water reactor power plant.

The main difference between the BONUS reactor and other boiling water reactors is the amount of heat applied to the steam before it drives the turbine generator. Scientists in the 1950s and ‘60s wanted to try superheating steam beyond normal temperatures. It was thought this could increase efficiency and produce more electricity
than a normal nuclear power plant. BONUS was built to test this theory.

An Experimental Powerhouse

Superheated Steam Drives the Turbines at BONUS

Unlike other boiling water reactors, the BONUS reactor made steam in the center of the reactor core and then heated it in four surrounding “superheaters.” This superheated steam then drove a turbine generator to produce electricity. While water boils to steam at 212 F (100 C), BONUS was able to heat steam to 900 F (482 C) . This temperature is about 350 F (176 C) greater than a normal boiling water reactor. BONUS was able to produce up to 50 megawatts (MW) of heat — enough to power up to 200,000 homes!

Another unique part of the BONUS facility is the 190-foot diameter steel containment building, different from a typical nuclear power plant. The design is based on the “total containment principle”: the steel dome contains the reactor as well as the turbine generator, electrical equipment, and reactor control room. In other words, all parts of the plant are totally contained within the dome.

On April 13, 1964, the reactor achieved “criticality” — a sustained nuclear chain reaction. This was the first time nuclear electricity was produced in Latin America. When it was operating, all the electricity produced at BONUS was provided to area power stations and used by local residents.

A New Kind of Reactor

Reactor Technology Puts Theory to the Test

Today, the primary types of nuclear power plants in the United States are boiling water reactors and pressurized water reactors. BONUS was a new type of boiling water reactor power plant.

The main difference between the BONUS reactor and other boiling water reactors is the amount of heat applied to the steam before it drives the turbine generator. Scientists in the 1950s and ‘60s wanted to try superheating steam beyond normal temperatures. It was thought this could increase efficiency and produce more electricity
than a normal nuclear power plant. BONUS was built to test this theory.

An Experimental Powerhouse

Superheated Steam Drives the Turbines at BONUS

Unlike other boiling water reactors, the BONUS reactor made steam in the center of the reactor core and then heated it in four surrounding “superheaters.” This superheated steam then drove a turbine generator to produce electricity. While water boils to steam at 212 F (100 C), BONUS was able to heat steam to 900 F (482 C) . This temperature is about 350 F (176 C) greater than a normal boiling water reactor. BONUS was able to produce up to 50 megawatts (MW) of heat — enough to power up to 200,000 homes!

Another unique part of the BONUS facility is the 190-foot diameter steel containment building, different from a typical nuclear power plant. The design is based on the “total containment principle”: the steel dome contains the reactor as well as the turbine generator, electrical equipment, and reactor control room. In other words, all parts of the plant are totally contained within the dome.

On April 13, 1964, the reactor achieved “criticality” — a sustained nuclear chain reaction. This was the first time nuclear electricity was produced in Latin America. When it was operating, all the electricity produced at BONUS was provided to area power stations and used by local residents.
Mission Complete

Setting the Stage for Long-Term Stewardship

BONUS reached its goal of demonstrating the integral boiling-superheating concept. However, it was decided that operating BONUS would not be possible in the long-term. Ongoing technical challenges and expensive repairs made running the reactor difficult and costly. After four years of operating, the BONUS reactor was shut down in June 1968.

The Puerto Rico Water Resources Authority (PRWRA) oversaw the reactor shutdown between 1969 and 1970. During shutdown, all nuclear fuel was removed to the mainland United States and all pipes were cleaned. The reactor was encased in concrete, some low-level waste was entombed, and all other parts were decontaminated. The concrete cover, approved by the U.S. Nuclear Regulatory Commission, was engineered to last 140 years.

The BONUS site has remained secure and maintained for nearly 60 years. The covered reactor and steel containment dome are in good condition. In 2007, the BONUS site was added to the National Register of Historic Places for its contributions to nuclear science and its historical importance to Puerto Rico and Latin America.

Read more about BONUS’ Long-Term Surveillance and Maintenance plan here.

View the BONUS site’s enrollment at the National Register of Historic Places.

Mission Complete

Setting the Stage for Long-Term Stewardship

BONUS reached its goal of demonstrating the integral boiling-superheating concept. However, it was decided that operating BONUS would not be possible in the long-term. Ongoing technical challenges and expensive repairs made running the reactor difficult and costly. After four years of operating, the BONUS reactor was shut down in June 1968.

The Puerto Rico Water Resources Authority (PRWRA) oversaw the reactor shutdown between 1969 and 1970. During shutdown, all nuclear fuel was removed to the mainland United States and all pipes were cleaned. The reactor was encased in concrete, some low-level waste was entombed, and all other parts were decontaminated. The concrete cover, approved by the U.S. Nuclear Regulatory Commission, was engineered to last 140 years.

The BONUS site has remained secure and maintained for nearly 60 years. The covered reactor and steel containment dome are in good condition. In 2007, the BONUS site was added to the National Register of Historic Places for its contributions to nuclear science and its historical importance to Puerto Rico and Latin America.

Mission Complete

Setting the Stage for Long-Term Stewardship

BONUS reached its goal of demonstrating the integral boiling-superheating concept. However, it was decided that operating BONUS would not be possible in the long-term. Ongoing technical challenges and expensive repairs made running the reactor difficult and costly. After four years of operating, the BONUS reactor was shut down in June 1968.

The Puerto Rico Water Resources Authority (PRWRA) oversaw the reactor shutdown between 1969 and 1970. During shutdown, all nuclear fuel was removed to the mainland United States and all pipes were cleaned. The reactor was encased in concrete, some low-level waste was entombed, and all other parts were decontaminated. The concrete cover, approved by the U.S. Nuclear Regulatory Commission, was engineered to last 140 years.

The BONUS site has remained secure and maintained for nearly 60 years. The covered reactor and steel containment dome are in good condition. In 2007, the BONUS site was added to the National Register of Historic Places for its contributions to nuclear science and its historical importance to Puerto Rico and Latin America.