ELSEVIER Desalination 157 (2003) 269-276

DESALINATION

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Water resources and potential of seawater desalination in Shandong peninsula

Yuhua Wang "*, Yajun Zhang b, Wenxiang Zheng b ~'Shandong Provincial Development Committee, Jinan 250011, P.R. China

Fax + 86 (531) 6901857; email. yuhuaw@sanlian, com. cn ~'lnstitute of Nuclear Energy Technology (INET), Tsinghua University, Beijing 100084, P.R. China

f'ax + 86 (1 O) 62771150; emails: yajun@dns, inet. tsinghua, edu. cn; zwx-ine@tsinghua, edu. cn

Received 19 December 2002; accepted 30 December 2002

Abstract

Shandong peninsula in the Northeast China has suffered a very serious water shortage in recent years. This paper presents the water resources of this region and the various means for solving the water shortage, particularly the nuclear seawater desalination in a large scale.

Keywords: Water resources; Freshwater shortage; Seawater desalination; Multi-effect distillation; Nuclear desalination; Nuclear heating reactor

1. I n t r o d u c t i o n

A worsening freshwater shortage has become a major concern worldwide. Northern China is one of the regions suffering from freshwater shortage in the world, and as a part of the area, Shandong peninsula is facing a particularly grim situation. Its freshwater resource per capita is only one sixth of the national average value. In order to mitigate

*Corresponding author.

the freshwater shortage in the peninsula, various measures have been taken by the Shandong provincial government in recent years, including participating in a national project called "Trans- ferring Water from the South to the North", and working on various seawater desalination projects.

The east route of the national project will pass through western Shandong, and a portion of the water transferred through the route will be intro- duced to the peninsula. Meanwhile different actions

Presented at the European Cor!ferenee on Desalination and the ['2nvironment: l+esh Water for All, Malta, 4 8 May 2003. European Desalination Socie&, International Water Association.

0011-9164/03/$- See front matter © 2003 Elsevier Science B.V. All rights reserved PII: S0011-9164(03)00406-5

270 Y Wang et aL / Desalination 157 (2003) 269-276

have been taken to encourage seawater desalination, including using reverse osmosis (RO) in some small desalination plant as well as using multi- stage flash (MSF) and multi-effect distillation (MED) process for desalination in some seaside power plants. In addition, a pre-project study of the Shandong nuclear seawater desalination plant (SNDP) was carried out in 2001 and a review on the study report has been completed recently. The SNDP will produce 160,000 m3/d &potable water and provide a base for further construction of the desalination units for coastal regions in China.

The freshwater resources and some current measures taken for mitigating water shortage in the region are presented firstly, and then the outline of the SNDP and main results from the pre-project study are given in the paper.

2. Water resources and water shortage situation in Shandong peninsula

Shandong province , the "hometown of Confucius and Mencius", is located on the east coast of China, the lower reaches of the Yellow River. Shandong faces the Japan chain islands and the Korean Peninsula to the east. Occupying a total land area of 156,700 km 2, the province now possesses a population of 90.4 million people with a population density of 579/km 2, in which the agricultural population accounts for about 70%. Shandong's major economic indicators rank the first among the provinces in China. In 2001, its gross domestic product (GDP) reached 943.8 billion RMB, which is among the top five in China. Shandong peninsula, the biggest peninsula in China, possesses more than 3,100 km of coast- line, 299 islands and piscary area of 170,000 km 2 in the offshore area. It generates 70% of the total GDP of the province, and its export and foreign investment accounts for 80% of that for the province while its population and land area accounts for 50%. However, as mentioned above, the peninsula is one of the driest areas in China. The average rainfall is 650 mm/y. The average

total fresh water per capita is 357 m 3, which is just 1/6 of that of the national average and 1/24 of the world average. Along with its economic and social development, it has suffered from freshwater shortage since 1980's. In the summer of 2000, for example, with consecutive years of drought, the emergency measures have been taken by the authorities to counter serious water shortage occurred. The quota policy was adopted in the year with freshwater per capita per month lowered from 2 m 3 down to 1 mL The fine for the water overuse was raised from 10 yuan/m 3 to 40 yuan. This seriously affected the living standard of more than 3 million people in 22 cities. The water shortage also seriously affected the normal industry production. 80% of industrial workshops were shut down at that time. While the overuse of underground water causes serious seawater invasion to the areas round about 1000 km 2, which in turn deteriorated the environment.

According to the statistics and projections, after the consideration of water reuse and possible water saving measures, the total water shortage volumes of the peninsula at present time are 2.3, 3, 4 billion m 3 with the guarantee rate of 50%, 75%, 95% respectively. The projected water shortage volumes in the year 2010 are 3, 4.9, 6.1 billion m 3 with the above respective guarantee rates. Overall, Shandong peninsula is a region of water shortage and little potential for further water resource exploration .In order to mitigate and even to solve the water shortage problem, some important projects are under construction or under consideration.

3. Brief introductions to some projects

3.1. TransJer water project

Because of the severe water shortage in north- ern China and the abundance of water resources in the south, Chinese government is going to implement the huge national project called "transferring water from the south to the north". There are three routes including West route,

Y Wang et al./Desalination 157 (2003) 269-276 271

Middle route and East route. In the East route the water will be transferred from Yantse River in Jiangsu province to Shandong province and finally to Tianjin with the transfer capability of 4.6 billion m -~ in the year of 2010 and 10 billion in the year 2030. The total investment of the East route pro- ject is about US$ 5 billion, and the total length of the East route is about 1000 km. The East route will pass through western Shandong province, and therefore, the local government is conducting the feasibility study of transferring the water to the east part of Shandong, Shandong peninsula (see Fig. 1). The projected water volume allocated to Shandong province is about 900 million m 3. The "transferring water from the west to the east" project in Shangdong will cost US$1.15 billion and the total length is about 700 km .The estimated cost is about US$ 0.5/m 3. The major debate about the project is how to deal with the serious polluted water along the route. The total investment will rise dramatically if the cost of controlling the pollution is included and this will affect the competitiveness of the project compared with other means.

3.2. Seawater desalination

3.2.1. Small RO plants

There are 3 seawater desalination plants by RO process in Shandong province at present. Their capacities of water production are in the range of 100 t/d to 5000 t/d. The water production cost is about US$ l/t, and the process is most suitable for some small areas and islands with small water demands. The major problems for these plants are the high cost and the fact that some of the key materials need to be imported fi'om foreign countries.

3.2. 2. Small MSF and MED plants

There are several small MSF and MED sea- water desalination plants in seaside power stations for their own use, which include Weihai power station, Huangdao power station in Tsingdao, etc.

It is encouraged to build some more such plants in the seaside power stations not only for their own use but also for water supply to the nearby areas.

3.3.3. Seawater desalination using nuclear energy

An interest in seawater desalination using nuclear energy, particularly using the nuclear heating reactor developed by the INET, has been shown by Chinese government in recent years. Therefore, some studies on the practical options for the demonstration of nuclear desalination have been conducted by the INET. The following sections will give a general description of the SNDR

4. The outl ine o f S h a n d o n g nuc lear desalination plant

In order to specify the concept of the nuclear desalination technology and verify its technical feasibility and economic viability, a pre-project study of the SNDP had been carried out in 2001 [1].

The technical base for the SNDP is to use a 200 MWth nuclear heating reactor (NHR-200) as a heat source and couple it to the MED process for desalination.

Fig. 2 shows the cross section of the N HR-200. It is a vessel type light water reactor. To achieve its safety goal and economic viability, the NHR- 200 has been designed with a number of advanced and innovative features [2,3], including the inte- grated arrangement, natural circulation, self- pressurized performance, in vessel control rod drive and passive safety systems. The core is located at the bottom of the reactor pressure vessel (RPV). Six primary heat exchangers are arranged on the periphery in the upper part of the RPV. The primary system pressure is maintained by the partial pressure of inert gas and steam. Reactor coolant circulates due to density differences between the "hot" and "cold" regions in the RPV.

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7

Fig. 1. East route of the National Transfer Water Project.

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Fig. 2. Cross section of the NHR-200. 1, reactor core; 2, control rod; 3, spent fuel storage; 4, PHEs; 5, RPV; 6, tight containment; 7, pipe for secondary loop.

There is no emergency core cooling system in the NHR-200. The residual heat removal system is the most important safety system and is designed as a passive system. The decay heat will be dis- persed into the ultimate heat sink by triple natural circulation.

Key accident analyses have been conducted to evaluate the overall performance of the NHR- 200. The results have shown that the NHR-200 core will never be uncovered and proper fuel cooling is ensured. The minimum DNBR is always greater than the safe limit. The integrity of the coolant pressure boundary will be properly maintained. Furthermore, the release of radioactivity will be

much less than the prescribed limits and fresh water produced will never be contaminated.

The MED high tempera ture namely the vertical tube foamy flow evaporation (VTFE) process was chosen due to relatively low energy consumption and fine flexibility under partial load operation, as well as better matching the NHR configuration.

The NHR-200 provides the desalination plant with 126°C saturated steams via the primary circuit, an intermediate circuit and a steam supply circuit. In the first effect of the VTFE, the steam is condensed by the seawater and then flows back to steam generators as feed water. The seawater heated by the motive steam in the first effect becomes secondary steam, which goes into the next effect as a heat source to evaporate seawater. Such evaporation-condensation process repeats further until the last effect. The fresh water is produced as condensate.

The SNDP will have a capacity of 160,000 mVd of potable water. Its key design data are given in Table 1.

As seen in Fig. 3 and Table 1, there are three physical barriers and one pressure barrier between the NHR-200 and the end user to prevent radio- activity from transferring to the product water.

The total base investment cost of the SNDP based on the price level in January 2001 is 1,270 million RMB (MRMB), equivalent to 158.4 MUSD, of which the base investment cost of the NHR-200 and its auxiliaries is about 460 MRMB or 55.56 MUSD, and the desalination plant base inves tment is 810 MRMB or 97.83 MUSD. The highest possibility of national participation is taken into account in the above cost estimation.

The main parameters used in calculating the water production cost include construction lead time, economic life, load factor, discount rate, capital charges, interest during the construction period, nuclear fuel cycle cost, and operation and maintenance costs.

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Table 1 Main design parameters of SNDP

Reactor thermal power, MW 200 Primary circuit and reactor core Pressure, MPa 2.5 Temperature of core inlet/outlet, °C 155/212 Core high, mm 1900 Core equivalent d iameter, mm 2210 Fuel assembly numbers 120 Initial fuel loading, t 18.0 RPV diameter, m 4.82

Intermediate circuit Pressure, MPa 3.0 Water temperature at SG outlet/inlet, °C 135/165

Steam supply circuit Steam pressure, MPa 0.24 Steam temperature, °C 126

Seawater desalination plant Water production capacity, m;/d 160,000 Desalination process MED-VTFE Number of units 2 Number of effects of each unit 30 Capacity per unit, m3/d 80,500 GOR* 21.6 Design temperature of seawater, °C 20 Water quality (TDS*), ppm _<20

*GOR and TDS refer to gain-output ratio and total dissolved solids, respectively

factor, construction time as well as duties and taxes have been pe r fo rmed to evaluate their influences on the water production cost. Table 2 shows an economic data summary for the SNDR

5. Conc lud ing remarks

Based on the discussions above and the con- sideration on circumstance of its water demand and supply, it can be concluded that the freshwater shortage problem in Shandong peninsula will be getting more serious if no strong and effective actions are taken immediately. Therefore the fol- lowing comprehensive measures should be imple- mented timely and effectively: 1) Transferring water project

With the implementing o f the national projects, Shandong province should double its effort to

Table 2 Economic data summary

Plant thermal power~ MW 200 Base construction cost of NHR-200, 460/55.56 MRMB/MUSD

Base construction cost of2x80,500 m3/d 810/97.83 MED water plant, MRMB/MUSD

Interest during construction period, % 6.5 Water plant capacity, m3/d 160,000 Construction lead time, month 42 Economic life time, y 30 Load factor, % 90 Discount rate, % 8 Levelized water production cost, 3.75/0.45 RMB/m~/USD/m 3

raise the necessary investment to construct its "transferring water from west to east" project. Accord ing to the plan, the wate r v o l u m e transferred from the South China to the region is 900 million in 3 in the year 2010. However, this amount o f allocation is far not enough compared with its water shortage. Applying for more water from the national project may come into consideration.

2) Adopting favorable policies to support the seawater usage

• Seawater desalination in some small islands using RO process, the government is going to build about 30 o f RO desalination plants with total freshwater production volume up to 0.1 billion m 3 in the year 2010.

• Seawater desalination in the coastal power plants for the f reshwater supply to nearby areas, the total freshwater production can reach 50 million m 3 in 8 power plants in the year 2010.

• Building 1 to 2 large scale water desalination plants using nuclear heating reactor mentioned before, the total production volume is about 0.1 billion m 3 in the year 2010.

With the above projects completed by the year 2010, the water shortage problems in Shandong peninsula will be partially solved, and the normal

276 E Wang el al. / Desalination 157 (2003) 269-276

life of the people and a moderate economic growth of the region can be guaranteed.

References

[l] Pre-proiect Study of the Shandong Nuclear Seawater Desalination Demonstration Plant, INBT, Tsinghua University, Beijing , China, August 2001

[2] D.Z. Wang and W.X. Zheng, Nuclear heating reactoi, an advanced and passive reactor, Proc. 9th Pacitic Basin Nuclear Conference, Sydney, Australia, 1994, pp. 303-307.

[3] D.Z. Wang, W.X. Zheng et al., Research and develop- ment of nuclear heating reactors in China, Tsinghua Science and Technology, 1(l)(1996) 1-7.