Spent fuel pool

These "temporary" storage facilities were constructed with the understanding that the federal government would eventually devise a comprehensive plan for the collection, transport, and disposal of these most dangerous of all radioactive wastes. The most common system devised for "temporary storage were spent fuel pools. Spent fuel pools are structures like swimming pools, with dimensions of about 40 feet by 60 feet (15 meters by 20 meters). Spent fuel from... 

Nuclear waste is often stored in spent-fuel pools that cover the spent fuel with at least 6 m of water. This amount of water prevents radiation from the waste from harming people. Nuclear waste can also be stored in a tightly sealed steel container. These containers have inert gases that surround the waste. These containers can also be surrounded by steel or concrete. Most of the nuclear waste that is put into a container has first been put in a spent-fuel pool to cool for about one year. 

The earthquake caused extensive damage to the structures of the Fukushima—Daiichi power plant and knocked out the pump systems that supply cooling water to the reactors and the spent fuel pools. This is known as a Loss of Coolant Accident (LOCA) takes place. 

Inadvertent blockage of flow through primary circulation loop Loss of cooling of the spent fuel pool. 

While core damage frequency may be zero for those utilities that choose to off load fuel from the reactor vessel to the spent fuel pool, the shutdown PSA must account for the new location of the fuel and calculations should be performed to determine the susceptibility of the fuel damage in its new location. 

Enhance the availability of the residual heat removal function by requiring alternative cooling methods (i.e. spent fuel pool cooling system). 

Interlocks were designed to prevent opening of specific isolation valves in lines connected to the RCS and the spent fuel pool. 

Almost all the radioactive products are contained in fuel located in the reactor itself or in used fuel which is still stored at the plant, in the spent fuel pool or, less frequently, in dry containers for temporary storage. 

Spent Fuel Pool Cooling and Cleanup System... 

Spent Fuel Pool Area Ventilation System... 

Nuclear industry in some countries are requiring support and time to evaluate technically and economically different options to launch their spent fuel management program. Adequate design criteria for the temporal storage capability in the spent fuel pools must be developed for advanced reactors. 

Fuelhandling accidents Fuel assembly jamming or breaking off during its installation in the spent fuel pool by the refuelling machine BDBA... 

CHAPTER 11. CORROSION RESISTANCE OF DIFFERENT ALUMINIUM ALLOY COUPONS IN THE SPENT FUEL POOL OF THE MIR REACTOR, DIMITROVGRAD, RUSSIAN FEDERATION. 179... 

Main features of spent fuel pool operation in the MIR reactor. 180... 

The reactor pool is divided into two sections. The first section is the core pool, where the core and irradiation facilities are located. The second section is the spent fuel pool, where the spent fuel storage racks are located. Some of the FAs in this section of the reactor pool had been in storage for only a short time others had been in the pool for almost 40 years, 30 of these years in the spent fuel racks. Some of these FAs had pit nodules visible to the naked eye. The pool water quality was and continues to be excellent pH is always maintained at between 5.5 and 6.5, the conductivity at below 2 aS/cm and the chloride content at less than 0.5 ppm. 

The racks were photographed as they were removed from the pool, they were disassembled, and the pH of the water on the surface of the coupons as well as in the crevice of the couples was measured. Ihe two sides of the coupons were photographed, then cleaned in deionized water and air-dried, and then-surfaces were examined with a magnifying glass. Figures 6.1(a)-(c) show the main features of the coupons after exposure to the spent fuel pool. 

TABLE 9.1. CHEMICAL ANALYSIS OF THE SPENT FUEL POOL WATER AND RADIATION FIELD MEASUREMENTS CARRIED OUT DURING EXPOSURE OF TEST COUPON RACKS TO THE POOL... 

The first batch of coupons was received in August 1996 at the first RCM, held in Budapest in 1996. The second batch of coupons was received at the second RCM, held in Sao Paulo in 1998. The investigation consisted of exposing the coupons to the aqueous conditions of research reactor spent fuel pools periodic inspection of the coupons, both visually and with photographs and the determination of corrosion product weight gains. 

At the State Scientific Centre of the Russian Federation, Research Institute of Atomic Reactors, the investigations were carried out at the spent fuel pool of the MIR research reactor. This chapter presents the following ... 

The coupons of the three racks were 3 mm thick discs with diameters of 100 or 70 mm and a 30 mm central hole. The coupons of rack 1 were assembled, either individually or as couples, and were separated with ceramic insulating discs. The coupons of racks 2 and 3 were similar in diameter. Unlike the coupons of rack 1, those of rack 2 appeared polished. The coupons in all the racks included small SS 316 discs. Prior to disassembly and coupon preparation, the racks were stored away from corrosive chemicals. Coupon preparation consisted of degreasing with ethyl alcohol followed by rinsing with deionized water. The coupons were then dried, weighed in a VLR-200 analytical balance (accuracy 0.0005 g), assembled in the rack and placed in the spent fuel pool of the MIR reactor. 

MAIN FEATURES OF SPENT FUEL POOL OPERATION IN THE MIR REACTOR... 

The spent fuel pool of the MIR reactor is a pit 11 m in diameter and filled with distilled water (about 20001). The pool walls are lined with stainless steel 1X18H10T. All the equipment and apphances for spent product storage are made of the same steel. Leaktight boxes can be used to store FAs with breached cladding. The refuelling tools are made of both stainless steel and SZAV-6 aluminium alloy. 

Rack 1 was inspected four times, and racks 2 and 3 were inspected twice during the period they remained immersed in the spent fuel pool of the MIR reactor. During these inspections, the racks were removed from the pool and the coupons were disassembled, dried, weighed, photographed (macro- and microphotographs), reassembled in the rack in the same order and returned to the same position in the pool. 

TABLE 11.1. PARAMETERS OF THE SPENT FUEL POOL COOLANT BEFORE IT PASSES THROUGH THE ION EXCHANGE PURIFICATION SYSTEM... 

A submerged pump was used to collect spent fuel pool water samples from a depth of 3 m and from close to the coupon rack. The following parameters were measured without pretreatment ... 

Periodically the Radiation Measurement Division of the Office of Atomic Energy for Peace (OAEP) measured the radiation field as absorbed dose in air at three different locations close to the coupons. In March 1999, most of the MTR type spent fuel was shipped back to its origin in the USA, and the radiation field measurements were no longer carried out. Since February 2000, the spent fuel pool is also being used as interim storage for a Co source. The activity of the source is estimated to be 425 Ci (1.57 x 10 Bq). 

Racks 2 and 3 were received at the second RCM. Just before loading these racks into the spent fuel pool, the coupons were removed and photographed. The coupons were not given any surface treatment. Rack 2 was loaded on 1998-03-18 about 50 cm from the side and above MTR type spent fuel assembly No. 12. Rack 3 was immersed in a different location about 3 m below the pool surface and also 50 cm from the side wall. The coupon arrangement was as received. 

SUPARIT, N., SUKHARN, S., BUSAMONGKOL, A., LAOHAROJANA-PHAND, S., Water chemistry management of the spent-fuel pool in Thailand , Proc. 6th Asian Symp. on Research Reactors, Mito City, Japan, 1999, Japan Atomic Energy Research Soc. (1999). 

This report documents the work performed in the IAEA Co-ordinated Research Project (CRP) on Corrosion of Research Reactor Aluminium Clad Spent Fuel in Water. The project consisted of the exposure of standard racks of corrosion coupons in the spent fuel pools of the participating research reactor laboratories and the evaluation of the coupons after predetermined exposure times, along with periodic monitoring of the storage water. The project was overseen by a supervisory group consisting of experts in the field, who also contributed a state of the art review that is included in this report. 

Component cooling water system Spent fuel pool cooling and cleanup system Residual heat removal system Essential service water system... 

During reftielling operations the containment dome and the reactor vessel head are removed, and the cavity above the dome is filled with water. The reactor internals are lifted out in sections, and placed in the water-filled cavity. The refuelling is carried out with a conventional refuelling machine from the reactor service room. Fresh fuel is brought into the cavity from a fresh fuel storage in the reactor building, and the spent fuel is removed to an adjacent spent fuel pool at the reactor service room floor level. 

Other auxiliary systems are the radioactive effluents treatment system, the components intermediate cooling system, the spent-fuel pool cooling and purification system. 

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