Boiling Nuclear Superheater (BONUS)

Rincón, Puerto Rico

Boiling Nuclear Superheater (BONUS) Reactor Overview

The decommissioned Boiling Nuclear Superheater (BONUS) reactor, located northwest of Rincón, Puerto Rico, was developed in the 1960’s as a prototype nuclear power plant to investigate the technical and economic feasibility of the integral boiling-superheating concept. This small-scale nuclear reactor produced saturated steam in the central portion of the reactor core, superheated it in four surrounding “superheater” sections of the same core, and then used the superheated steam in a direct loop to drive a turbine generator.

The BONUS facility was the eighth nuclear power plant constructed in the world and first in Latin America. It was one of only two boiling-water superheater reactors ever developed in the United States.  The BONUS reactor first went critical on April 13, 1964, and was operated intermittently from 1964 to 1968, after which operations were discontinued, and the facility was decommissioned. The facility was decontaminated to a safe occupational exposure condition in accordance with standards in place at that time. These activities were completed in 1970.

El reactor desmantelado de BONUS, ubicado al noroeste de Rincón, Puerto Rico, fue desarrollado en la década de 1960 como un prototipo de planta de energía nuclear para investigar la viabilidad técnica y económica del concepto integral de sobrecalentamiento en ebullición.

La planta BONUS fue la octava central nuclear construida en el mundo y la primera en América Latina. Fue uno de los dos únicos reactores de sobrecalentamiento de agua en ebullición desarrollados en Estados Unidos. El reactor BONUS entró en criticidad el 13 de abril de 1964 y funcionó de manera intermitente desde 1964 a 1968, después de lo cual se suspendieron las operaciones y la planta fue desmantelada. 

Current Status

The Boiling Nuclear Superheater (BONUS) facility is owned by Department of Energy (DOE) Legacy Management (LM) and the Puerto Rico Electric Power Authority (PREPA). The US Army Corps of Engineers (USACE) has partnered with DOE LM to complete a Historical Site Assessment and Site Investigation with the objective to identify chemical, radiological, and other hazards that exist at the BONUS site, to identify potential exposure to the hazards, and to provide input to future site decision making.

The Boiling Nuclear Superheater (BONUS) Decommissioned Reactor Site remains secure and well-maintained near Rincón, Puerto Rico. All primary structures, including the entombed reactor system and containment dome, are in good post-decommissioning condition.

El reactor “Boiling Nuclear Superheater (BONUS)” o Sobrecalentador Nuclear en Ebullición es una propiedad de la Autoridad de Energía Eléctrica de Puerto Rico (AEE). El Departamento de Energía (DOE), laOficina de Manejo del Legado o “Legacy Management” (LM) y el Cuerpo de Ingenieros del Ejército de los Estados Unidos (USACE) se han asociado para completar una evaluación del sitio histórico.

Policy for Operations of Unmanned Aircraft Systems (UAS, e.g. Drones)

As part of the Historical Site Assessment, USACE is working with DOE LM to capture aerial imagery of this historical site using an unmanned aircraft systems (UAS) in November 2024. It is incumbent upon visitors of DOE site to know the rules concerning use of UAS, such as drones. UAS pose a potential risk to personnel, safety, infrastructure, equipment and mission conduct.

UAS pose a potential risk to personnel, safety, infrastructure, equipment and mission conduct. In accordance with Title 36 CFR, Parks, Forest and Public Property, Parts 327.4(b) and (c), UAS are prohibited from flying over any DOE or USACE projects without explicit authorization from DOE. If a person is operating a UAS in undesignated areas, without exclusive permission, or recklessly, local law enforcement may be called upon. LM and USACE has obtained all necessary approvals to conduct the UAS aerial survey in November.

Los drones representan un riesgo potencial para el personal, la seguridad, la infraestructura, el equipo y la realización de la misión. De acuerdo con el Título 36 del CFR, Parques, Bosques y Propiedad Pública, Partes 327.4(b) y (c), los drones tienen prohibido volar sobre cualquier proyecto del DOE o del USACE sin la autorización explícita del DOE. Si una persona opera un drone en áreas no designadas, sin permiso exclusivo o de manera imprudente, se puede recurrir a la policía local. LM y USACE han obtenido todas las aprobaciones necesarias para realizar el reconocimiento aéreo de drones en noviembre.

BONUS Location

Department of Energy Project Site
Department of Energy Project Factsheet
USACE Project Factsheet & Drone Info
USACE Factsheet & Drone Info (Español)

Contact Information

USACE project inbox: cenab-bonus@usace.army.mil