TRANSPORT OF RADIOACTIVE WASTE IN DUKOVANY NUCLEAR POWER PLANT

J. KULOVANY

Nuclear Power Plant Dukovany, Dukovany, Czech Republic

Abstract

Article, describes the system of raduiaste transport an Uukovany NPP = gaseous, liquid and solid waste of .low level and intermediate level activity. There are different kinds of the transport in the reactor unit and on the uiay from the waste treatment facilities to the disposal. The article describes also waste composition, transport containers and new Czech raduiaste disposal.

In conformity with the valid Czech legislation, radioactive wastes belong to dangerous wastes . Their transport is rather different in dependence on the waste kind /state, chemical composition, and activity/ and on the route Öl-transport .

Radwaste transport in the Czech Republic is regulated by the regulation of the Ministry of Health No. 59/1972 Coll.

on "Protection Against Ionizing Radiation" and another regulation No. 67/1987 Coll. on "Ensurance of Nuclear Safety during Handling with Radioactive Wastes", issued by the former Czechoslovak Atomic Energy Committee, far ts of Czechoslovak State Standards CSN 341731.1 "Regulations for Working Places with Radioactive Substances", iiv:,ut--:d In

l'jr>!j, and CSN 41 1141 )U "Transport Packing Sets f-or RadLu.icti.vc Substances", issued in 19Q>>. concern the above -im.Tihionud matter. Details on transport conditions art:

given an thr: regulations uf single mm Lstries and, in reality, they give the provisions of tht.- signed international treatit-s on transport of dangerous substances hy train, by roads, by water, and by air.

Transport of gaseoui::, raduiastes is done autoinatically by a oyotfiw n(" air conditions 119 ventilators and pipjnn. Durinq transport, the air from less contaminated spaces yoes through possibly contaminated spaces into the gas cleaiiinq plant. After cleaning it is let out by a 15 U m high ventilation stack.

In accordance with regulation No. 67/1987 Coll. there is an effort to minimalize the transport of liquid radwastes in casks in the Dukovany Plant technology. All in all, this possibility is used in the design only for transport of-continoent contaminated drainage water from the regional raduiaste storage facility within NPP Dukovany premises, located about 4OU in from the Dukovany Unit No. 4.

In conformity with the CAEC regulation No. 67/L987.

transport of liquid radwastes is done through pipang primarily. This is done within the reactor unit as well as to the building of radwaste solidification. A piping bridge transports liquid radioactive concentrates and ion-exchange resins through outdoor line in the length of 31 JU m in the summertime. It is made of stainless steel piping with certificate, connected by X-ray checked welds.

All the three piping lines /for concentrates, for

~ion--exehan<jt-: resins, and stand— by line/ are covered. For thr r.ase of contingent leakage, there is a collection

trough which would lead off the liquid back to the control zone .

For transport of contaminated water from outside buildings into the power plant there is a special transport cask for liquid radwastes. It 1-3 made of stainless material with certificate and has a safety tank for collection of leakages. It can be transported by a crane and on a truck.

It is planned mostly for transport of drainage water from radwaste sturagt; facility which may be contaminated .

Solid radwastes are transported within the plant premises as follows: Common small waste is collected at designated places within the plant control zone from where it is transported in plastic bags by hand or electric trucks into the auxiliary building. After a selection of non-active objects waste is deposited here for several years. Waste sorting is done in a half-automatic dosimetric apparatus - sorting carousel and sorting box. It makes possible to sort out BOX of non-active ob jects from solid waste . These sorted out non-active wastes may be incinerated in a not i-active incineration plant . In addition to the planned transports we had to cope with transport of large-size ob jects, viz . racks from spent fuel ponds . Large-size metal ob jects are partially decontaminated and then transported to outside radwaste storage. With regard to a low exposure rate the transport is done without a cask. Metal objects have to be completely dry after decontamination and then they are put, in a plastic cover, on wooden beams on the truck body. After checking of tyres cleanness the truck leaves the control zone and .within one minute it reaches the radwaste storage place where it goes into controj zone again. Metal objects are taken by a forklift onto the prepared beams. The transport is not permitted to b<: done during rain or snowfall.

Thn transport of solid combustible radwaste into the incineration plant is solved at present and its implementation begins. Combustible waste is collected in the: auxiliary build mg. Auxiliary building No 2 stands next to the planned location of the incineration plant. Radwaste is collected in box pallets. In each pallet there are 5-8 polyethylene bags uiith waste. Tht?se pallets are placed into a shielded cask which, under a special regime, goes into the lift, shaft, from where it goes by lift onto a load truck which will transport it to auxiliary building No. 2 by a similar lift. Box pallets with waste from all the plant Units are transported through an inner gate directly into the incineration plant where they will be destroyed.

One of the most important procedures is the transport of solidified raduaste in barrels into the regional spent fuel storage facility. It is a surface storage facility for low-and middle-active waste. It contains four rows of pits in double lines. The rows contain seven dilatation parts with four pits each. Each of 112 pits can hold approximately 12OO barrels for 200 1.

The total size of storage space is 55 45O cu.m. which corresponds to 13O 000 barrels. The waste handling is done by means of a gantry crane which moves along the lengthwise wains of the pits. The crane has two crabs. The larger one with capacity of 12.5 t serves for handling of panels and casks. The lesser one with capacity up to l t serves for precise manipulation with barrels. This crab is provided with microtraverse and is controlled from a shielded box by means of a set. of earners. The crane may be also controlled remotely From the operation building /to the length of as much as 2UH m/. It is pmvided with several lifting attachment!:;. Movable shield covers the opened tank and

serves also for transport of barrels taken out of the cask.

In addition to barrel cask there are three basic types of transport casks. The casks are put on a transport frame of a semi-trailer. An eigth-barrel cask weighing 2310 kg is used fur low-active waste. P'or middle-active waste, four-barrel casks of a cylinder shape, weighing 3 YOU kg and fc>2UU kg, are used. For relatively highest activities, one-barrel casks, weighing 4OOO kg and t>O8U kg, are used.

Treated radwaste in the form of bitumen composition is closed in 2OO 1 metal barrels. In spit« of a short distance between the building of radwaste treatment from the storage facility /about 5OO m/, the transport is done by special technical means. The barrels are put into the storage pits in six layers in vertical position and gradually covered by a concrete mixture. Putting into carriers or casks is done by a crane in the building of radwaste treatment. The casks are put into the transport frame located on a semi-trailer in the despatch hall of this building. Under a special regime the semi-trailer goes from the restricted area towards the storage facility by the shortest way. The despatch hall is designed in such a way that the semi-trailer with transport frame need not go back but it drives through the hall. With regard to large quantity of transported radwaste, there are special safety and warning provisions for the case of an accident outside the restricted area. There are emergency procedures for accident with fall and rupture of a barrel and for the case of vehicle fire. After the rupture of a barrel the bitumen composition usually does not desintegrate because it is rather soft. It is very slightly inflammable and it is self-quenching. After a ten-minute burning the tire would be qupnrhed by the resulting salt crust- A fall into a water source has not been analysed as the route is chosen in such a manner that it avoids all water tanks or water

streams. Even with the maximum spsed ot- 3D kins per hour the distance between the two ob jects xs covered within 2 minutes.

Within the precincts of the radwaste storage facility wastes are taken over and the semi-trailer is transported under the gantry crane. Here the barrels are taken out of the earn ers or casks and placed onto the transport Platform. Barrels with platform are transported by the qantry crane to the now filled pit arid put _in the alloted spacp. Then the barrels will be covered by concrete mixture. This storage facility serves for permanent storing of all low- and middle-active wastes from NPP Dukovany and NPP femelin. It is fully completed and prepared to store radwastes. Their bitumenation shall begin at NPP Dukovany within a few months.

At present the transport of raduastes from NPP Temelin to the storage facility at NPP Dukovany is sub jected to an intensive research. Two road routes were chosen. The usual route is 176 km long and is planned for transport in good weather conditions. The reserve route is planned for transport at worse road conditions and higher weight of the semi-trailer. It is 189 km long. Until the beginning of NPP Temelin operation other roads may be constructed, with qood carrying capacity of bridges, sufficient width and low slope. Nevertheless their safety checking and approval is a long-time matter, especially from the viewpoint of individual solution of all possxble accidents wxth water streams, which cannot be fully avoided." Mostly one-barrel casks with bitumination product and also pressed waste for the incineration plant will be transported . The possibility of transport of vitrified product is evaluated which would be exceptionally resistant against water. Iransport of

small quantities:; of other radwaste and dress parts to bu washed will be done in casks too, but it is not completely solved as yet..

The transport of radwaste from Temelin to Dukovany by road is a certain risk for smooth operation of the Czech Power Enterprises Co. The risk is connected with bad road conditions in winter time or during heavy rain and also with political influences and public acceptance. T_n spite that it is possible to stop the transport even for several months it has been decided to evolve a method of transport of raduiaste by train. The preferable way is the transport of a semi-trailer without towing vehicle on a waggon. Two semi-trailers can be put on a special waggon at the same time. The variant of the transport of the casks directly on the waggon is a more complicated one as for handling, because then it is necessary to transload the casks and to provide the storage facility with a railway siding. But from the legislation point of view, any transport by train is more simple because it is not necessary. when seeking approval, to negotiate with single district authorities as in the case of transport by road.

A PLAN OF RADIOACTIVE WASTE MANAGEMENT IN CHINA

X. WANG

Bureau of Nuclear Fuel,

China National Nuclear Corporation, Beijing, China

Abstract

China has been developing nuclear industry for more than three decades. In these activities, considerable quantity of various radioactive waste has been accu-mulated. By 1992, the accumulated solid and liquid Low- and Intermediate-Level Waste (LILW) had totaled to 41,000m3 in China. Along with the utiliza-tion and development of nuclear energy, the increasing quantity of radioactive waste is required to be appropriately treated and disposed of. It is estimated that the accumulated LILW in China will be 173,000m3 by 2010. In order to better utilize and develop nuclear energy, to protect environment, China has formulat-ed a plan on appropriate treatment and disposal of LILW, and implementation of this plan is undergoing. My introduction will be with emphasis on the plan of LILW management in China.

1 INTRODUCTION

The basic objective of radioactive waste management is, through treatment and disposal of radioactive waste with a safe and effective way, to prevent ra-dioactive nuclide releasing to environment with an unacceptable quantity, and to make exposure to staff and public now or in future be within the authorized limit and be As Low As Reasonable Achievable (ALARA), further more, so as to protect mankind and its environment.

We have formulated the policy on solid LILW management, minimizing waste generation, collecting with waste segregation, volume reduction and stabi-lization, firm packaging, interim storage in situ, safe transportation, and re-gional disposal. For liquid LILW, concentrates processed by evaporation, ion ex-change and filter are first put into interim storage in situ, then be solidified to stable form. The main solidification processes used in our country include;

ce-mentation and bituminization. After appropriate packaging, dry solid waste and solidified waste will be transported to disposal site for final disposal.

2 CONDITIONING

Some kind of waste must be solidified and packaged to convert waste to a form that is suitable for transportation , storage and disposal. The solidification technology used in our country include cementation , bituminization and solidifi-cation with other agents specially developed.

The plant to solidify low level liquid concentrate with bitumen was put into hot trial operation in 1992. The plant was equipped with two independent process lines. The main process equipment on each process line is a rotary scraper with a throughput of solidifying Low Level Liquid Waste (LLLW) of 200~250 liters per hour. The result of trial operation is very satisfactory. 500m3 of LLLW has been solidified with bitumen in 1993.

The first nuclear power plant in China —— Qinshan Nuclear Power Plant produces about 4 Om³ /a of LLLW concentrates with specific activity ranged from 2. 3X 106Bq/l to 2. 3X 107Bq/l. The concentrates are solidified with a in-drum cementation process. Solid waste produced in Qinshan Nuclear Power Plant is to-tally 220m3(1100 drum) each year.

For intermediate level liquid waste (ILLW) , two kind of cement solidifica-tion technology have been chosen : underground hydrofracture process with ce-ment, and in situ bulk grouting with cement. Both processes combine treatment and disposal , and are not only safe but also economic. The treatment capacities of the two processes are also quite high.

Based on design, hydrofracture process can treat and disposal of 300~350 m3 of ILLW per 8 hours. It is planned to operate 4 ~ 6 cycle ( 8 hours per cycle) each year. The disposal capacity of each hydrofracture well is more than 10000m3. Waste will be disposed of in the various layers undergroud from 400

~300m. The key factor of this process is whether a geologically and hydrologi-cally suitable site can be found near a reprocessing plant. Through about 10 years relevant research and development, the suitable cementation formulation has been developed and an underground hydrofracture test with radioactive tracer has been completed. It is demonstrated that the site is suitable for disposal of ILLW with undergroud hydrofracture process. The engineering design of this project has

been completed, and the construction started. It is expected that disposal of ILLW with this process will begin in 1995.

The process of in situ bulk grouting with cement can only be used in the spe-cific site which is suitable for shallow land disposal of ILLW. Radioactive waste, cement and additives are mixed in a mixer and then continuously poured into un-derground pools with dimension of 8m X 8m X 6m. Each pool is equipped with a double vane mixer. The plant for in situ bulk grouting is located at Lanzhou Nu-clear Fuel Complex (LNFC). The site is located in Gobi Desert where is sparsely populated and arid climate, and the groundwater level is between 38. 9 and 40.

2m. Engineering cold test and conceptual design of the project have been com-pleted. Engineering design and preparations for construction are actively con-ducted. Construction work of this project will be actively conducted in this year, and hot operation of in situ grouting of ILLW will begin in 1995.

3 TRANSPORTATION

Solid waste and solidified waste produced in nuclear power plant is interimly stored in site for about 5 years, it shall then be transported to volume reduction center or final disposal site. Based on the locations of nuclear power plant and disposal site, transportation can be carried out either by rail, road, water or by combination of them. All transportation shall be carried out in accordance with the regulations for transportation of radioactive materials, and all packaging of radioactive materials shall strictly fulfill relevant regulations and standards.

At present, practice experience on radioactive waste transportation in China is very limited, it is necessary to learn relevant experience and lessons from other country. In the other hand, it is essential to establish a sound system of radioac-tive transportation, which includes transportation carrier, shielding and shipping container, transport modes and routes, authority in charge of transportation as well as a perfect surveillance system.

Because the development of nuclear power in China is still in a initial stage, the quantity of waste produced is very limited comparing with countries in which nuclear power are developed. Although the policy of LILW disposal is regional disposal, it is not necessary at present for our country to built more disposal facil-ities , because operation of disposal facility can be cost-benefit only when the fa-cility has a reasonable scale. Even though the nuclear power is developed to a

considerable scale in China, it is impracticable for each nuclear power plant to construct and operate a disposal site. It means that transportation of radioactive waste is also a unavoidable issue that must be solved.

Most countries have promulgated regulations on radioactive materials trans-portation which will also regulate radioactive waste transtrans-portation. IAEA has promulgated a Regulation for Safe Transportation of Radioactive Materials.

These regulations provide requirements on the radioactive quantity limits of each packaging, shielding, and surface contaminations of packaging as well as packag-ing quality control requirements etc. Based on IAEA Regulations for Transporta-tion of Radioactive Materials, China formulated "GB-11806-89 RegulaTransporta-tion on safe transportation of radioactive materials" in 1989.

In order to smoothly conduct works relevant to LILW disposal in our coun-try , we will make efforts on research of transportation of radioactive waste. On the basis of extensive research on experience and lessons of radioactive waste transportation of other countries, the feasibility research of transportation of LILW will be carried out. The safety of transportation of radioactive waste is achieved through strictly implementing the relevant regulations and rules. We will also formulate radioactive waste transportation rules which meets conditions

In order to smoothly conduct works relevant to LILW disposal in our coun-try , we will make efforts on research of transportation of radioactive waste. On the basis of extensive research on experience and lessons of radioactive waste transportation of other countries, the feasibility research of transportation of LILW will be carried out. The safety of transportation of radioactive waste is achieved through strictly implementing the relevant regulations and rules. We will also formulate radioactive waste transportation rules which meets conditions