Water Use and Consumption in Nuclear Power Plants
What are the two main areas of water consumption and usage in a nuclear power plant?
Water is used:
1. In cooling systems for dissipation of generated heat
2. for industrial and potable service for plant service and operation
What is the difference between open-cycle cooling and closed-cycle cooling system?
Open-cycle cooling system takes water from a natural source, such as a river, lake, or ocean, uses it for cooling, and then returns it to its original source.
While, closed-cycle cooling system recirculates a fixed volume of water within a closed system, where the water is cooled and reused.
Fill in the blank:
A water treatment facility supplies _____ quality water to industrial plants, thermal, and nuclear power plants.
High
Which schemes can be used to reduce water use in open-loop cooling systems?
1. Variable speed cooling pumps for part load or load following operation.
2. Variable speed drives on cooling pumps for temperature variations in the source of water.
3. Variable speed drives on cooling pumps for tidal variations in the source of water.
Select:
A. Only 1
B. 1 and 2
C. 2 and 3
D. 1, 2, and 3
D. 1, 2, and 3.
True or False?
As it is expected that water will become less and less available in the future and regulation will get more strict (if not prohibitive), the once-through or open-cycle system, today being the most efficient and economical cooling technology for an NPP, will probably be less common.
True.
What are the four major phases of water management in a Nuclear Power Plant?
1. Construction
2. Commissioning
3. Operation
4. Decommissioning
Fill in the blank:
Closed cycle cooling systems may use ______, _______, or _________ type of cooling.
wet cooling, dry cooling or hybrid (wet and dry)
What is water treatment technology primarily used for?
Water treatment technologies remove or neutralize impurities, making the water suitable for either consumption (freshwater) or discharge (wastewater effluent).
True or False?
The calcium hardness in the cooling tower should be maintained within the range of 350 to 400 ppm on a non-acid treatment programme.
True.
Fill in the blank:
The tritium concentration in water effluents can be reduced to acceptable discharge levels by processing the water through an ______ bed.
Adsorption.
What are the main sources of heat dissipation during normal plant operation?
1. Spent fuel pool
2. Cooling of components
3. Coolant treatment
4. Chillers and ventilation
True or false?
Wet cooling towers reduce the total volume of water withdrawal from the environment by nearly 95% compared to once-through cooling.
True.
True or False?
In some places, including Singapore and California's Orange County, reclaimed water (recycled water; former wastewater (sewage) that has been treated to remove solids and certain impurities) can be used indirectly for drinking when a more advanced treatment is made.
True
Fill in the blank:
Non-chemical treatment methods can be carried by adapting latest technologies of microfiltration (MF), ultrafiltration (UF), nano-filtration (NF), reverse osmosis (RO), and ______ ______.
Electro Dialysis.
What technology was used to increase the storage capacity of fuel pools over the past 15-20 years?
A) Low density spent fuel storage
B) High density spent fuel storage
C) Medium density spent fuel storage
D) Low burn-up fuel storage
B) High density spent fuel storage
True or False?
Consumption and water utilization heavily depends upon the type of reactor (for example pressurized heavy water reactor (PHWR), pressurized water reactors (PWR), boiling water reactors (BWR), etc.) used in a nuclear power plant.
False.
It varies more with the plant size and the number of employees.
True or false?
The water that is evaporated from the tower is impure; as it contains trace amounts of mineral solids that were dissolved in the cooling water.
False.
The water that is evaporated from the tower is pure; that is, it doesn’t contain any of the mineral solids that are dissolved in the cooling water.
How is water deionized/demineralized?
In order to demineralize water, the cation impurities are exchanged for hydrogen (H+) in a hydrogen cycle cation exchanger and the anion impurities are exchanged for hydroxyl (OH–) ions in a hydroxide cycle anion exchanger.
An option to reduce water withdrawal or consumption in cooling systems is to reduce waste heat rejection. Heat rejection to the environment is reduced by increasing plant efficiency or by using excess heat for a thermal application. Several low temperature applications could use part of the waste heat from the nuclear power plant reducing the amount of heat rejected in the condenser.
State 2 possible low heat applications.
— District heating
— Heat for industrial applications
— Thermal desalination
— Aquaculture and Agriculture: Extensive pond aquaculture, animal shelters, algal ponds, intensive raceway aquaculture, undersoil heating, greenhouses.
What is a key factor determining the total treatment costs for the bithermal hydrogen-water process?
A) Temperature control
B) Types of catalysts used
C) Operating duration and power cost
D) The number of cold-stripping columns
C) Operating duration and power cost
During the cool down of the plant to cold shutdown state, the dissipated heat transported by the nuclear service water reaches a _______, as the stored heat and the residual heat from the primary circuit will be transferred to the ultimate heat sink.
maximum
What type of water has a low temperature variation between winter and summer time and a very large reservoir for water withdrawal?
Sea water
State 3 advantages and disadvantages of once-through (open-loop) cooling system.
Advantages:
- Simple
- Uses least amount of equipment
- Low capital and operating costs
- Consumes the least water
- Greatest thermal efficiency
Disadvantages:
- Thermal discharge plumes
- High volume of water intake
- Entrainment
- Impingement
- In-stream flow maintenance
Name 5 basic water quality parameters that need to be maintained in a cooling tower loop.
- Ca
- Ca x S04
- Ca with PO4 present
- Mg x SiO2
- HCO3 + CO3
- SO4
- SiO2
- Fe (Total)
- Mn
- Cu
- Al
- S
- NH3
- pH
- pH with SO4 present
- TDS
- TSS
- BOD
- COD
The next generation of reactors is being developed according to the framework by the GIF (Generation IV international forum) that was chartered in 2001. State 2 goals they have set for the upcoming year.
- Sustainability: Generation IV nuclear energy systems will provide sustainable energy generation that meets clean air objectives and promotes long term availability of systems and effective fuel utilization for worldwide energy production.
- Economics: Generation IV nuclear energy systems will have a clear life-cycle cost advantage over other energy sources. They will have a level of financial risk comparable to other energy projects.
- Safety and reliability: Generation IV nuclear energy systems operations will excel in safety and reliability. They will have a very low likelihood and degree of reactor core damage. They will eliminate the need for offsite emergency response.
- Proliferation resistance and physical protection: Generation IV nuclear energy systems will increase the assurance that they are a very unattractive and the least desirable route for diversion or theft of weapons usable materials, and provide increased physical protection against acts of terrorism.