Ground source and nuclear energy

Question 1

What are geothermal energy systems like?

Answer 1

Deep, high pressure and temperature
systems, typically several hundred to
1,000 m depth

Question 2

What is closed system geothermal energy production?

Answer 2

water (and heat)trapped at depth; no or slow natural
recharge; water pumped to depththrough injection well where it heats, and then pumped (or rises) through extraction well

Question 3

What is open system geothermal energy production?

Answer 3

water naturally recharges through groundwater flow; water escapes through hot springs, geysers and diffusion into water cycle. Often only uses extraction well only

Question 4

Why is extraction balance needed for geothermal?

Answer 4

To avoid cooling

Question 5

What is geothemrla enegry production associated with?

Answer 5

VOlcanic activity

Question 6

Why is geothermal not really underaken in the UK?

Answer 6

Old geology which has majority cooled still adequate for ground heating

Question 7

What is the supply roblem for geothermal energy?

Answer 7

Very local supply for maybe a town or city but not nationally with globa supply easily be matched by a small amount of other power generation methods

Question 8

What is ground source heat like?

Answer 8

Shallow geothermal energy, low pressure and temperature

Question 9

Why is ground source heating under utilised in the uk?

Answer 9

Lack of financial incentive with systems being expensive

Question 10

What is ground source heat used for?

Answer 10

Space / domestic heating

Question 11

What is the cost to run ground source heating once installed?

Answer 11

Low about that of an american freezer and only take 5-10 yrs to pay off

Question 12

What are open system ground source heat pumps?

Answer 12

Exchanges heat with surface waters naturally occurring in ground

Question 13

What water bodies can be used for open system groud heat pumps?

Answer 13

Ponds (can heat source) or aquifers

Question 14

How does closed loop ground source heat pump work?

Answer 14

Uses boreholes (vertical systems) or shallow
trenches (horizontal systems) within unconsolidated ground (drift deposits, e.g. soils, tills, boulder clays, etc.) cycling same water in pipes. Water in closed system so not released into environment

Question 15

What is cheaper installing a gas boiler or ground source heat pump?

Answer 15

Boiler ~3000 compared to 21000

Question 16

What are tailings?

Answer 16

waste from uranum mining

Question 17

What is the typical ore deposits % for urananium?

Answer 17

0.1-2%
1000-20000 ppm

Question 18

Who are the biggest extractors of uranium?

Answer 18

Was russia until USSR dissolved then khazakstan

Question 19

WHat are some events that have affected uranium price?

Answer 19

Financial crash increase as might have been important resource
Fukishima fall in price
Increase recently due to energy resource speculation

Question 20

What are isotopes?

Answer 20

Same element & protons, different number of neutrons

Question 21

What is the abundance of Uranium problem?

Answer 21

Want U235 but 238 most abundant so expensive processing to split

Question 22

How are pellets used to make fuel rods?

Answer 22

U gas compressed to form pellets which are baked then placed in rods for power stations

Question 23

What process produecs energy from nuclear?

Answer 23

Fission so atom spilt creating a self perpetuating cycle heating water creating stewam and driving a turbine

Question 24

proc

What are the types of radioactive emission from nuclear?

Answer 24

Alpha (stop by paper)
Beta (stopped by aluminium)
Gamma (stopped by lead)

Question 25

What is used to slow/ stop nuclear reactors?

Answer 25

Control rods

Question 26

What probkem does the UK have with nuclear energy?

Answer 26

Has a backlog of waste which has not be stored or dealt with

Question 27

What storage is required for Low Level Waste?

Answer 27

actions for the protection of people
but not so much that it requires shielding in handling or storage
Shallow burial

Question 28

What proportion of waste is LLW?

Answer 28

Bulk of waste– 90% by volume, 1% by activity

Question 29

What problemw ith LLW vaults is there? (uk example)

Answer 29

Produced on human timescale but what about beyond this
Uk - drigg - runout to sea in emergencies instead of land

Question 30

What is the UK LLW site called?

Answer 30

Drigg - ~850000m3 LLW
110 hectares

Question 31

What is Intermediate level waste ILW?

Answer 31

Higher levels of radioactivity
Includes resins, chemical sludge, metal fuel cladding and contaminated materials from reactor decommissioning

Question 32

What storage has to be done for ILW?

Answer 32

Requires shielding
May be solidified in concrete or bitumen for disposal

Question 33

Where is all high level waste stored?

Answer 33

In nuclear power stations

Question 34

What % of radioactivty come from HLW?

Answer 34

95

Question 35

What is the planned storage of HLW with a poor example?

Answer 35

Underground storage
poor example is russia leaving nuclear subs in a dry dock

Question 36

What is vitrification for HLW storage?

Answer 36

encapsulated into molten glass and poured into stainless steel
canisters

Question 37

How has the cost of storage for nuclear waste chnaged from 2015 to 2023?

Answer 37

Estimated cost in 2015: £85 billion
Estimated cost in 2023: £260 billion
UK spends c. £ 4.2 billion per year (2.96 from gov, 1.17 from revenue)

Question 38

What are the characteristics of deep geological disposal of HLW?

Answer 38

250 – 1,000m underground
* Passive system
* No retrieval
* Multi-barrier system – engineered & natural barriers

Question 39

What are the problems with deep geological storage of HLW?

Answer 39

safety, cost, public attitude, stability over
long timescales

Question 40

What are the geological considerations for storage of HLW underground?

Answer 40

Stability – no erosion or tectonic movement
Integrity – relatively few faults, fractures, fissures
Hydrogeology – little groundwater flow
Geochemistry – sorbing minerals & reducing conditions