Naval Reactors Facility

Naval Reactors Facility

Idaho National Laboratory (INL) Before Naval Reactors

On Feb. 18, 1949, the U.S. Atomic Energy Commission announced it would be building its National Reactor Testing Station on the Naval Proving Ground in eastern Idaho. The Idaho site was chosen over a more remote site in Montana based on socio-economic factors, namely nearby towns that could absorb new population. In April, AEC named Leonard "Bill" Johnston as its field office manager. In May, the announcement came that the commission's headquarters would be located in Idaho Falls.

On Dec. 20, 1951, Argonne's Experimental Breeder Reactor No. 1 (EBR-I) produced enough electricity to power four lightbulbs. From this modest start, the civilian application of nuclear energy became a reality. EBR-I achieved full-power operation the next day. The liquid metal sodium-potassium alloy (NaK) used as coolant produced a high-temperature low-pressure operation, both conducive to efficient power production. In 1953, EBR-I proved that a nuclear reactor designed to operate in the high-energy neutron range could create more fuel than it consumed (“breeding”).

The second reactor built in Idaho, the Materials Testing Reactor, went critical on March 31, 1952, and was brought up to full power on May 22, 1952, becoming mankind’s first nuclear reactor for testing materials. The Argonne-designed MTR was a keystone of the AEC’s postwar reactor development program. In addition to subjecting potential reactor fuels and structural materials to irradiation, MTR’s “beam holes” made cross-sectioning and other physics research possible. The reactor’s eventual power output was 40 megawatts. In 1958, it became the first water-cooled reactor to operate using plutonium-239, demonstrating that a plutonium-fueled reactor could be controlled satisfactorily. The pioneering work at MTR influenced reactor design throughout the free world.

Early NR Prototypes

S1W - In 1950 construction started on the Submarine Thermal Reactor which marked the birth of America’s nuclear navy. The prototype reactor, which was cooled and moderated by pressurized water, and the propulsion equipment were built at Idaho’s Naval Reactors Facility. The reactor and support systems were located inside a hull section duplicating the size and specifications of the USS Nautilus, the Navy’s first nuclear-powered submarine, which was under construction in Connecticut at the time. To facilitate shielding research, a tank of water surrounded a portion of the hull. Before the Nautilus was launched, S1W and its crew simulated a 96-hour voyage from Newfoundland to Ireland. For decades, the reactor aided in the testing of advanced designs and provided training for sailors.

A1W - As nuclear technology evolved, the U.S. Navy adapted nuclear power to surface vessels. To support this effort, in 1956 Westinghouse started constructing the first nuclear-powered surface ship prototype, A1W, which consisted of two pressurized water reactors powering a single engine room. A1W was the prototype for the world’s first nuclear-powered aircraft carrier, USS Enterprise (CVN-65). The reactors achieved criticality in 1958 and 1959. The prototype also provided realistic training for reactor operators in an environment nearly identical to what they would encounter within the actual carrier. As the program evolved, new reactor cores and equipment replaced many of the original components. Naval personnel continued to train at the A1W plant until the mid-1990s.

Expended Core Facility

As the NNPP matured from supporting an experimental submarine program to one supporting a fleet of nuclear-powered ships, the need quickly developed for a dedicated facility to handle and examine the naval spent nuclear fuel assemblies. Based on this need, initial ECF construction began in early 1957.

The original ECF building was approximately 100 meters (340 feet) long by 60 meters (190 feet) wide with an approximately 18-meter (59-foot) high bay. The building contained a series of shielded cells and a water pool located in the center of the building that was approximately 10 meters (34 feet) wide, 15 meters (50 feet) long, and 6 meters (20 feet) deep. Since the original construction, the size of ECF increased significantly, through a series of expansions necessary to accommodate the expanding mission of the facility. The current water pool was constructed in four stages. The total length of the ECF water pool is now approximately 130 meters (420 feet), with pool depths ranging from approximately 6 to 14 meters (20 to 45 feet). The interconnected, reinforced concrete water pools contain 12.1 million liters (3.2 million gallons) of water, which is cooled to prevent algae growth and enhance clarity. The water levels in the water pools are maintained at a nearly constant level, with alarms to indicate both high-level and low-level conditions. ECF is currently approximately 305 meters (1000 feet) long and 60 meters (190 feet) wide, with an 18-meter (59-foot) high bay running the length of the building. The high bay area enclosing the water pools and servicing area has four large overhead cranes of 54 to 113 metric ton (60 to 125 U.S. ton) capacity.

One of the more significant mission changes occurred because of a 1992 DOE decision to discontinue reprocessing of naval spent nuclear fuel at INL. Until then, naval spent nuclear fuel was examined at ECF, structural hardware was removed from naval spent nuclear fuel assemblies, and the remaining portion of the naval spent nuclear fuel assembly was packaged and transported from NRF to another INL facility for reprocessing. When reprocessing was terminated, NRF’s mission expanded to include packaging of naval spent nuclear fuel for disposal.

Following the ECF expansions, additional facilities that interface with ECF were constructed to

package and temporarily store naval spent nuclear fuel in a dry condition consistent with the 1995 Settlement Agreement signed on 10/17/1995. This agreement between the DOE and the State of Idaho address Idaho concerns that Idaho was being used as a disposal site for nuclear weapons production activities outside of Idaho. the agreement recognizes important role that the facilities plays in the Naval Nuclear program. In pursuing the agreement, then Governor Batt had 3 guidelines: Idaho must not become a default repository for nuclear waste; the DOE needs to address the waste already in Idaho; and the INL must become a viable national laboratory. As part of the agreement, Naval Reactors would be allowed to bring limited quantities of Naval spent nuclear fuel into Idaho for 40 years (2035). There was also a stipulation that in support of this, a 2023 deadline for shifting from wet to dry storage.

In 2001, The Overpack Storage Building (OSB) was constructed to temporarily dry store naval spent nuclear fuel canisters packaged in concrete overpacks. Temporary dry storage capability is required pending transport of the naval spent nuclear fuel canisters to an interim storage facility or a geologic repository. The OSB has a thick, reinforced concrete floor, with a metal building to protect the overpacks from the elements; it houses approximately 50 concrete overpacks.

In 2003, operations began in an area of NRF that came to be known as the Spent Fuel Packaging Facility (SFPF). This facility supports packaging of naval spent nuclear fuel assemblies into naval spent nuclear fuel canisters, and loading of the naval spent nuclear fuel canisters into concrete overpacks. These capabilities enable naval spent nuclear fuel to be stored, on a temporary basis, in a dry shielded environment pending transport to an interim storage facility or geologic repository. The SFPF is an extension to ECF located at the southeastern end of the facility, connected to the water pools by covered water canal.

In 2004, Naval Reactors approached the State of Idaho to express uncertainty about NRF after 2035. As a result, the Navy Addendum of 2008 was reached where:

• All spent navy fuel arriving in Idaho before 2026 must leave Idaho by 2035

• Spent naval fuel arriving in Idaho after 2026 could stay as long as ''reasonably necessary'

• Limits the amount of spent naval fuel allowed to be in Idaho at any one point of time and as a running average

• Provides for archival retention of some spent nuclear fuel

The opening of an interim storage site or a geologic repository has been delayed from 2010 as

originally planned to beyond 2020. This delay necessitated an expansion to the OSB to continue to meet SA 1995 and SAA 2008 agreements. The first expansion (completed in 2010) is connected to the existing OSB and increased the storage capacity by approximately 70 concrete overpacks. A second storage expansion was completed to meet capacity demands until at least 2020. A third expansion will be necessary to meet capacity demands beyond 2020.

Spent Fuel Handling Facility

Naval Reactors determined that the existing Expended Core Facility requires recapitalization and decided to replace the legacy facility with the Spent Fuel Handling Facility (SFHP). The existing Expended Core Facility is also incapable of receiving full-length aircraft carrier naval spent nuclear fuel, which is required to support aircraft carrier refuelings. The magnitude of required sustainment efforts and incremental infrastructure upgrades within the Expended Core Facility pose substantial risk to the continued preparation of naval spent nuclear fuel for long term storage. Specifically, sustainment efforts could require delays to naval spent nuclear fuel shipping container unloading operations, which would interrupt refueling and defueling schedules for nuclear-powered vessels and would adversely affect the operational availability of the nuclear fleet. If this interruption were to extend over long periods of time, the ability to sustain fleet operations would be impacted, resulting ultimately in a significant decrement to the Navy's responsiveness and agility to fulfill military missions worldwide. A supporting Environmental Impact Statement was completed in 2016 and the National Environmental Policy Act Record of Decision was published on 12/5/2016. Construction officially started (CD-3) in 2018. As of 2024, the facility is still under construction with start of M-290 Shipping Container unloading operations expected in Q2 of FY2027.

Other Interesting Work at INL

First City Lit by Atomic Power - The Boiling Water Reactor experiments had their most public moment on July 17, 1955. Around midnight, BORAX-III, which had been connected to a 2,000-kilowatt turbine/ generator, produced enough power to light the nearby city of Arco as well as the BORAX Test Facility and the NRTS Central Facilities Area. On Aug. 12, officials announced the accomplishment at the UN’s first International Conference on Atomic Energy in Geneva, Switzerland. The Soviet Union, undoubtedly feeling upstaged, asserted that it hadn’t happened. Since then, Arco has proudly claimed the title of “First City Lit By Atomic Power.”

Aircraft Nuclear Propulsion Work - Starting in 1955, three Heat Transfer Experiments were conducted as part of the Aircraft Nuclear Propulsion (ANP) program, the U.S. Air Force’s attempt to develop a nuclear-powered jet aircraft. The program involved ground tests — the Heat Transfer Reactor Experiments. The first, HTRE-1, produced 20 megawatts of heat energy on a test stand at Test Area North’s Initial Engine Test Facility. HTRE-2 advanced the technology of high-heat ceramic reactor fuels, and HTRE-3 experiments eventually ran two turbojet engines at a time at 2,000 degrees F. A hangar was built and runway plans drafted, yet numerous safety concerns surrounded the project. On March 28, 1961, President John F. Kennedy canceled the ANP program, bringing work to an abrupt and permanent end.

SL-1 Accident - Part of the Army Nuclear Power Program, SL-1 was a prototype for reactors intended to provide electrical power and heat for small, remote military facilities, such as radar sites near the Arctic Circle, and those in the Distant Early Warning Line. The design power was 3 MW (thermal), but some 4.7 MW tests were performed in the months before the accident. Useful power output was 200 kW electrical and 400 kW for space heating. During the accident on January 3, 1961, the core power level reached nearly 20 GW in just four milliseconds, causing the explosion. The direct cause was the over-withdrawal of the central control rod that absorbed neutrons in the reactor's core. The accident released about 80 curies (3.0 TBq) of iodine-131, which was not considered significant, due to its location in the remote high desert of Eastern Idaho. About 1,100 curies (41 TBq) of fission products were released into the atmosphere. This accident lead to the wide-spread acceptance of a "one rod stuck" criteria which requires complete shutdown capability even with the most reactive rod stuck in the fully withdrawn position. This criteria was already in place for Naval Reactors designs as it is one of the initial reactor design criteria for Shippingport.

Advanced Test Reactor - When the AEC and the Navy requested a new test reactor with less neutron flux variation, the result was ATR. It first reached criticality on July 2, 1967, and reached its full 250-megawatt power level in August 1969, becoming the largest test reactor in the world. The reactor’s distinctive cloverleaf design offers a wide range of power levels to nine main test spaces or loops, each with its own distinct environment apart from that of the main reactor core. While its main customer was the U.S. Navy, ATR became the linchpin of a National Scientific User Facility in 2007, making it available to researchers across the U.S. and around the world. It completed its sixth core internals changeout in 2022 and remains in operation today.