What follows is not an essay plan but somes notes with information and ideas that might be useful in working out an essay plan.
Introduction – this title concerns two separate but connected topics, nuclear armaments and the development of nuclear power for peaceful purposes. It is also related to the dangers posed by other Weapons of Mass Destruction (WMDs).
Nuclear arms – some information

https://www.armscontrol.org/factsheets/Nuclearweaponswhohaswhat
There are currently 9 nuclear powers – the US (since 1945), the Russian Federation (1949), the UK (1952), France (1960), China (1964), Israel (1967?) , which now also has a submarine with nuclear arms and thus a second strike capability (2003), India (1974), Pakistan (declared 1998, probably developed from the 1970s), North Korea (2003). Apartheid South Africa had them and then eliminated them (1982-94). Canada deploys US missiles but has no independent control of them. Germany, Italy, Holland and Belgium and Turkey have US nuclear bases and are part of NATO's nuclear sharing policy

https://en.wikipedia.org/wiki/Nuclear_sharing

https://eu.boell.org/en/2016/05/25/european-union-and-nuclear-disarmament-sensitive-question

which means they take common decisions with the US on nuclear weapons policy and maintain technical equipment required for the use of nuclear weapons. Belarus, Kazakhstan and Ukraine had them after the break-up of the Soviet Union but returned them to the Russians almost immediately.
The Nuclear Non-Proliferation Treaty (1968) came into force in 1970. There was also the Partial Nuclear Test Ban Treaty (1963) and the Comprehensive Nuclear Test Ban Treaty (1998)
There are treaties concerning other potential Weapons of Mass Destruction (WMDs). These include the banning of Chemical weapons (1992), Biological weapons (1971) and Weapons in Outer Space (1967).
The Vienna-based International Atomic Energy Agency (IAEA) is responsible for monitoring the development of nuclear power for peaceful purposes (the production of energy for domestic and industrial consumption) and ensuring that nuclear materials and equipment are safe and not diverted from legitimate peaceful purposes to military purposes. (There is a similar Agency in the Hague for chemical products and the potential for producing chemical weapons.) The dispute, sanctions and recent deal between the UN and Iran (and the continuing support for, doubts about and criticism of the deal) demonstrate the difficulty of this task.
https://en.wikipedia.org/wiki/Iran_nuclear_deal_framework
http://www.nytimes.com/2016/01/18/opinion/a-safer-world-thanks-to-the-iran-deal.html
http://www.nytimes.com/2016/01/17/world/middleeast/iran-sanctions-lifted-nuclear-deal.html
http://www.telegraph.co.uk/news/worldnews/middleeast/iran/
Nuclear weapons
They are clearly expensive to built, maintain and update. Are they dangerous? Are they weapons that are likely to be used? Probably not in terms of whether states really intend to use them one day, although recent tensions between the US and North Korea are cause for concern. There are also worries that various other countries may try to develop weapons. Moreover, there is always the danger of an accident due to a technological or human error, and the threat of a decision taken by a madman. There is, in the case of India and Pakistan (as in the similar but slightly different case of the US and USSR during the Cuban crisis), the danger of escalation from a conventional conflict to a nuclear war in the Kashmir region. In addition, poorer countries may spend too little on maintenance and security systems (e.g. the 2-key launch system or Russia's security failures during and after the collapse of the Warsaw Pact and Soviet Union, 1989-91). So there is a good argument for trying to abolish them completely.

https://en.wikipedia.org/wiki/International_Campaign_to_Abolish_Nuclear_Weapons

However, an attack by a nuclear power on another nuclear power, or the ally of a nuclear power, would be suicidal (the Mad Doctrine of the Cold War). For example, an attack by a future Iran hypothetically in possession of nuclear weapons could destroy Israel but Israel would retaliate and destroy Iran. An attack on a non-nuclear power would lead to international isolation, if not a coordinated counter-attack from the global community or other nuclear powers (e.g. North Korea on South Korea). So the real danger may be that nuclear weapons or materials could fall into the hands of terrorists or be targeted by terrorist attacks (in Pakistan, for instance).
http://www.nci.org/nci-nt.htm
There is also the question of what would happen to the nuclear weapons in the event of a civil war in a state which has nuclear arms. This is a real danger in Pakistan and was one of the major international concerns during the break-up of the Soviet Union. The development of nuclear weapons is also related to the development of nuclear delivery systems (planes, short-range, long-range and intercontinental ballistic missiles – ICBMs) and the international community is involved in monitoring this situation, particularly regarding developments in this sector in Iran and North Korea.

Arguments in favour of keeping nuclear arms (the Devil’s advocate!)

(1) They, more than the UN, have prevented a Third World War for more than 65 years. There have been many conflicts, but none of them have been global. Without nuclear arms the US and USSR might have gone to war at some pointduring the Cold War . So their elimination might actually lead to more wars and make a general global conflict more likely. They have only been used once, by the US on Japan, to end a war, not to start one. This is a strong argument.

(2) No conventional war since 1945 has ever escalated into a nuclear war.

(3) Reductions in or the elimination of these weapons must be coordinated with reductions in other types of WMDs, or countries will invest in those alternative weapons and the real danger to the world may be increased, e.g. a race to develop and build biological weapons.

(4) If major powers reduce the number of nuclear weapons they have then they will probably massively increase their spending on conventional weapons to compensate for this. Some historians argue thar World War I demonstrated that a build-up of conventional weapons can lead to growing tensions and war.

(5) Nuclear weapons guarantee a country against invasion. So far this has been true.

(6) Nuclear weapons guarantee a country and a country’s allies against attack. This is not true. Argentina invaded the Falklands, confident that Britain would not respond with nuclear weapons. North Vietnam and the Viet Cong defeated the South Vietnamese government and US forces. Afghan rebels fought and defeated the Russians and the Russian-backed Afghan government. They were not intimidated by the strength of the US and USSR as nuclear powers.

(7) Nuclear weapons can be effectively used to threaten a non-nuclear country. This does not really seem to be true. Only North Korea has tried to use this tactic, against South Korea, and largely without success. The US, the USSR (Russia today), France, Britain, China, India, Pakistan – none of them has ever done this. Israel does not admit publicly that it has nuclear weapons and has fought a series of conventional wars with its neighbours. It has never threatened the use of nuclear weapons. It has threatened conventional bombing of Iranian nuclear research and development sites if the Iranians continued with their program.

(8) Prestige – This is a much-quoted but possibly mistaken idea. A country or government may, of course, believe that it will acquire status and prestige by developing nuclear weapons but this is probably an illusion as the following considerations suggest. Have North Korea and Pakistan really acquired international prestige or become regional leaders? Don’t Germany, Japan and Brazil have considerably more prestige because of their economic importance? Did China and India gain prestige internationally when they acquired nuclear weapons or when their economies expanded to their current levels? Does the prestige of the EU in international relations depend on French and British nuclear weapons ( or NATO forces and US weapons) or on its economic importance as a single developed market, democratic traditions and cultural influence? Do the Arabs respect Israel more because it has nuclear weapons?

(9) Nuclear technology is old, no longer complex (with the right fissile material you could built one at a US university physics department) and you cannot turn the clock backwards. You cannot get rid of knowledge. So should we try to eliminate them completely, or reduce their numbers and try to improve their safety, prevent their proliferation where this is possible, but accept that they are here to stay?

http://www.boell.de/intlpolitics/security/foreign-affairs-security-global-zero-nuclear-weapons-conference-8755.html
http://en.wikipedia.org/wiki/Nuclear_proliferation
http://en.wikipedia.org/wiki/Nuclear_weapon
http://en.wikipedia.org/wiki/List_of_states_with_nuclear_weapons
http://en.wikipedia.org/wiki/Nuclear_proliferation
http://www.globalissues.org/issue/67/nuclear-weapons
http://en.wikipedia.org/wiki/Nuclear_Non-Proliferation_Treaty
http://www.wagingpeace.org/articles/1997/00/00_babst_consequences.php

Treaty on the Prohibition of Nuclear Weapons

http://www.un.org/apps/news/story.asp?NewsID=57588#.Wmt-XLynFdg

https://en.wikipedia.org/wiki/Treaty_on_the_Prohibition_of_Nuclear_Weapons

Nuclear technology for the peaceful production of energy

https://www.carbonbrief.org/mapped-the-worlds-nuclear-power-plants
Nuclear power is widely used as a source of energy. Some examples – France has 58 nuclear power stations (or plants), producing 40% of the country's total energy production, 76% of its electrical power, the highest percentage in the world.
http://nuclearinfo.net/Nuclearpower/TheScienceOfNuclearPower
http://en.wikipedia.org/wiki/Nuclear_power
http://en.wikipedia.org/wiki/Nuclear_power_in_France

http://www.world-nuclear.org/information-library/country-profiles/countries-a-f/france.aspx
Germany has 8, producing 14% of its electrical power (compared to 22.4% in 2010 and 17 nuclear plants) but plans to phase out nuclear power by 2022.
http://en.wikipedia.org/wiki/Nuclear_power_in_Germany

http://www.world-nuclear.org/information-library/country-profiles/countries-g-n/germany.aspx
USA has 99, producing 19.47% of its electrical power. As of 2017, there are 2 new reactors under construction.http://en.wikipedia.org/wiki/Nuclear_power_in_the_United_States
Japan has 5 nuclear power stations in operation. Prior to the earthquake and tsunami of March 2011 Japan had generated 30% of its electrical power from nuclear reactors and planned to increase that share to 40%. After the disaster, all its 50 reactors were closed. Currently 42 reactors are operable and potentially able to restart. Five reactors have restarted to date, with the first two back online in August and October 2015. A further 21 reactors are in the process of restart approval.

http://en.wikipedia.org/wiki/Nuclear_power_in_Japan

http://www.world-nuclear.org/information-library/country-profiles/countries-g-n/japan-nuclear-power.aspx

https://en.wikipedia.org/wiki/Nuclear_power_phase-out
The UK has 15, producing 21% of its electrical power.

http://www.world-nuclear.org/information-library/country-profiles/countries-t-z/united-kingdom.aspx

http://en.wikipedia.org/wiki/Nuclear_power_in_the_United_Kingdom
For the history and current situation in Italy see:

http://www.world-nuclear.org/information-library/country-profiles/countries-g-n/italy.aspx

http://en.wikipedia.org/wiki/Nuclear_power_in_Italy
The Russian Federation currently has 35, producing 17.78% of its energy, but plans to increase the number of reactors to 59 and increase production to 25% by 2030.
http://en.wikipedia.org/wiki/Nuclear_power_in_Russia

http://network.bellona.org/content/uploads/sites/3/2017/05/2017-Russian-nuclear-power-NO-ISBN.pdf

http://www.world-nuclear.org/information-library/country-profiles/countries-o-s/russia-nuclear-power.aspx
The Chernobyl disaster was a nuclear accident that occurred in April 1986 at the Chernobyl Nuclear Power Plant in Ukraine, which was under the direct jurisdiction of the central authorities in Moscow. An explosion and fire released large quantities of radioactive material into the atmosphere. It is widely considered to have been the worst nuclear power plant accident in history. Highly radioactive fallout entered and contaminated the atmosphere and drifted over large parts of the western Soviet Union and Europe (large parts of Germany were covered with radioactive contamination). From 1986 to 2000, 350,400 people were evacuated and resettled from the most severely contaminated areas of Belarus, Russia, and Ukraine. According to official post-Soviet data about 60% of the fallout landed in Belarus. The accident raised concerns about the safety of Russian nuclear technology, as well as the dangers of nuclear power plant engineering in general and human error. Russia, Ukraine, and Belarus have been burdened with the continuing and substantial decontamination and health care costs of the Chernobyl accident. According to a report by the International Atomic Energy Agency estimates of the number of deaths potentially resulting from the accident vary enormously: Thirty one deaths are directly attributed to the accident, all among the reactor staff and emergency workers. An UNSCEAR report places the total confirmed deaths from radiation at 64 as of 2008. The World Health Organization (WHO) estimates that the death toll could reach 4,000 civilian deaths, a figure which does not include military clean-up worker casualties. The Union of Concerned Scientists estimate that for the broader population there will be 50,000 excess cancer cases resulting in 25,000 excess cancer deaths. The 2006 TORCH report predicted 30,000 to 60,000 cancer deaths as a result of Chernobyl fallout. A Greenpeace report puts this figure at 200,000 or more. A Russian publication, Chernobyl, concludes that 985,000 premature cancer deaths occurred worldwide between 1986 and 2004 as a result of radioactive contamination from Chernobyl. http://en.wikipedia.org/wiki/Chernobyl_disaster
The events following the failure of cooling systems at the Fukushima Daiichi I Nuclear Power Plant in Japan on March 11, 2011demonstrate that even with great advances in the safety of nuclear technology, exceptional events (in this case an earthquake and a tsunami) make 100% safety impossible and raise questions about the industry’s confident claims to operate within acceptable margins of safety.
http://en.wikipedia.org/wiki/Fukushima_Daiichi_Nuclear_Power_Plant
http://abcnews.go.com/topics/news/fukushima-nuclear-power-plant.htm
http://fukushimaupdate.com/
Many countries had already decided not to use or to phase out nuclear power:http://en.wikipedia.org/wiki/Nuclear_power_phase-out
after the Fukushima disaster other countries now plan to reduce or eliminate nuclear power:http://en.wikipedia.org/wiki/Nuclear_power_in_Germany
http://www.guardian.co.uk/world/2012/sep/14/japan-end-nuclear-power
http://www.thedailybeast.com/newsweek/2011/11/27/post-fukushima-nuclear-power-changes-latitudes.html
http://nuclearstreet.com/nuclear_power_industry_news/b/nuclear_power_news/archive/2011/11/04/mexico_1920_s-energy-plans-swap-nuclear-for-natural-gas-110401.aspx
The production of nuclear energy produces radioactive waste materials that need to be stored on a long-term basis (for centuries). The French nuclear power industry’s claims that a very high percentage of this material can be recycled is widely disputed. Moreover, this is not what is happening in most countries at the moment. So this material also represents a threat to life. For example, experts argue that in the US alone, 70 years after the Manhattan project began, there are now 99 nuclear reactors and 177 tanks containing 71,862 tons of nuclear waste (the product of both the commercial and defence nuclear reactors) in temporary(!) storage facilities with no permanent storage arrangements. (see: http://www.huffingtonpost.com/2011/03/23/us-nuclear-waste-radioactive-storage_n_839438.html
Moreover, those who argue that nuclear energy is cheap often ignore the fact that any eventual solution that is found for the disposal of this waste is liable to be expensive and needs to included in calculating the real cost of producing such energy.

http://www.world-nuclear.org/information-library/nuclear-fuel-cycle/fuel-recycling/processing-of-used-nuclear-fuel.aspx

https://en.wikipedia.org/wiki/High-level_radioactive_waste_management

http://www.nytimes.com/cwire/2009/05/18/18climatewire-is-the-solution-to-the-us-nuclear-waste-prob-12208.html?pagewanted=all
http://www.prnewswire.com/news-releases/ieer-french-style-nuclear-reprocessing-will-not-solve-us-nuclear-waste-problems-90233522.html
http://spectrum.ieee.org/energy/nuclear/nuclear-wasteland
http://www.guardian.co.uk/science/blog/2011/apr/04/fear-nuclear-power-fukushima-risks
http://en.wikipedia.org/wiki/Dual-use_technology
http://en.wikipedia.org/wiki/Thorium_fuel_cycle
The argument for maintaining the existing power plants, at least in the short term, is that fossil fuel alternatives are limited (but with flow prices in 2016-17 and additional shale gas and oil reserves this argument now seems weak) and polluting, and alternative clean renewable energy sources are only in their infancy and cannot offer adequate supplies at the moment. Opponents argue that renewables are becoming competitive and that, anyway, this argument only underlines the need for greater investment in renewables in order to produce a technological revolution and lower costs dramatically. Supporters of nuclear power also argue that the two major accidents which happened were in Soviet Russia, using poor technology and under a government system that was well-known for its inefficiency, and in Japan, in an area where a nuclear power plant should never have been built because of seismic risks. Moreover, advocates of nuclear energy claim that more people die, directly or indirectly, in the coal-mining industry and oil industry than die in the nuclear industry and statistics from the International Energy Agency seem to confirm this:
http://www.newscientist.com/article/mg20928053.600-fossil-fuels-are-far-deadlier-than-nuclear-power.html#.UvlL-fvrVbg
However, there are several arguments for closing these power stations. First, there is the danger of an accident like the ones described above. Moreover, in Europe the EU clearly needs to adopt a common policy since the effects of an accident in France could easily spread to Italy, Spain, the UK, Belgium, Switzerland and Germany. Secondly, closing them will force countries to invest heavily and rapidly in alternative renewable energy sources. Thirdly, they are potentially vulnerable targets for terrorists , e.g. an attack on a nuclear facility could lead to a nuclear disaster (e.g. by using a plane), or a raid to acquire nuclear materials or waste (or simply the purchase of these materials from corrupt officials) for the construction of a ‘dirty’(or ‘suitcase’) bomb for a terrorist attack (using conventional explosives to release radioactive material into the atmosphere). The fewer the nuclear plants the less nuclear material there is to protect.
http://www.nci.org/nci-nt.htm
The International Atomic Energy Agency (IAEA) is the international organization which is responsible for promoting the peaceful use of nuclear energy, and trying to prevent its development and use for any military purpose, including nuclear weapons. The IAEA was established as an autonomous organization in 1957 but reports to both the UN General Assembly and Security Council . As the IAEA points out there is no simple clear line between nuclear energy for peaceful purposes and nuclear energy for military purposes. So preventing the proliferation of nuclear weapons in a world in which nuclear energy is widely used for energy production is becoming an extremely difficult, if not impossible, task.
Nuclear weapons today
The US and the Russian Federation have made large reductions in their nuclear arsenals through a negotiation process which began with the START 1 treaty in 1991 (also START 2, START 3, SORT) and say they are committed to continuing this process (the New START treaty was ratified in January 2011). From a high of 65,000 active weapons in 1985, there are now estimated to be some 4,120 active nuclear warheads and some 14,930 total nuclear warheads in the world in 2015.The US has reduced from 32,000 (active and stockpiled) at the highest point in 1966 to 1,800 (active warheads) and 6,800 (total inventory including reserves and stockpiles)
The USSR/Russian Federation has reduced from 45,000 (active and stockpiled) at the highest point in 1988 to 1,950 (active) and 7,000 (total inventory)
The following estimates from the Federation of American Scientists, September 2017.
See this text for an explanation of the figures. http://fas.org/issues/nuclear-weapons/status-world-nuclear-forces/

Status of World Nuclear Forces 2017*
Country	Deployed Strategic	Deployed Nonstrategic	Reserve/ Nondeployed	Military Stockpilea	Total Inventoryb
Russia	1,950	0	2,350	4,300	7000
United States	1,650	150	2,200	4000	6800
France	280	n.a.	10	300	300
China	0	?	270	270	270
United Kingdom	120	n.a.	95	215	215
Israel	0	n.a.	80	80	80
Pakistan	0	n.a.	120-130	120-130	120-130
India	0	n.a.	110-120	110-120	110-120
North Korea	0	n.a.	?	?	?
Total:s	~4,150	~150	~5,300	~9,400	~14,930

http://en.wikipedia.org/wiki/Nuclear_disarmament
http://en.wikipedia.org/wiki/Nuclear_weapon
http://newsoffice.mit.edu/2014/rose-gottenmoeller-america-russia-nuclear-security-1024

http://www.icanw.org/the-facts/nuclear-arsenals/
“Since 1991, the United States [claims that it] has destroyed about 90 percent of its non-strategic nuclear weapons and devalued them in its military posture. Recently, however, the Obama administration has reaffirmed the importance of retaining some non-strategic nuclear weapons to extend a nuclear deterrent to allies. And the U.S. Congress has made further reductions in U.S. nuclear weapons conditioned on reducing the “disparity” in Russian non-strategic nuclear forces.

Russia says it has destroyed 75 percent of its Cold War stockpile of non-strategic nuclear weapons, but is insisting that at least some of the remaining weapons are needed to counter NATO’s conventional superiority and to defend its border with China. Following a meeting of the NATO-Russia Council on April 19, 2012, Russian Foreign Minister Sergey Lavrov stated: “Unlike Russian non-strategic nuclear weapons, U.S. weapons are deployed outside the country,” and added that “before talks on the matter could begin, the positions of both sides should be considered on an equal basis.”

from: http://www.fas.org/_docs/Non_Strategic_Nuclear_Weapons.pdf

The US withdrew from the ABM Treaty (1972) in 2002 (which banned the development of a missile defence system).

http://www.nytimes.com/2001/12/13/international/bush-pulls-out-of-abm-treaty-putin-calls-move-a-mistake.html

At the November 2010 NATO Summit in Lisbon, NATO’s leaders decided to develop a ballistic missile defence (BMD) capability to pursue its core task of collective defence and specifically against an attack with missiles. Despite NATO’s initial attempts to reach agreement with the Russian Federation, Russia has made its opposition to the plan clear. (Moreover, many technical experts doubt that such a system will ever be 100% effective, which is the only level of safety worth having if the missiles have nuclear warheads.) This and the situation in Ukraine have raised tensions with Russia and could put at risks the prospects for further cooperation between the US and Russia on nuclear arms reductions.

http://www.nationaldefensemagazine.org/articles/2017/7/31/nato-missile-defense-systems-strive-for-interoperability

Worsening relations between the US, NATO and the Russian Federation (due to events in Ukraine and the NATO missile defense system) have put future negotiations and progress on further reductions at risk. Here is the latest news as of September 2017:

https://www.armscontrol.org/act/2017-09/news/disputes-cloud-us-russian-arms-talks

Both sides now seem to be set on a new nuclear arms race.

https://www.youtube.com/watch?v=ZOxhsrQH7Yw

https://www.theguardian.com/world/2018/mar/01/vladimir-putin-threatens-arms-race-with-new-missiles-announcement

In October 2018 President Donald Trump said the US will withdraw from the 1987 Intermediate-Range Nuclear Forces (INF) treaty claiming that Russia had violated it. The deal banned ground-launched medium-range missiles, with a range of between 500 and 5,500km (310-3,400 miles. e.g. Moscow to Paris). There are concerns that without a new understanding between the US and Russia we could now see the unravelling of all the progress made in the last 25 years and a new nuclear arms race.

In contrast, former US President Obama had talked about the need for an international commitment to eliminate nuclear arms completely. Realistically, this is unlikely to happen in the near future, without the prospect of some kind of world government. Some experts even doubt the advisability of such a development.

http://en.wikipedia.org/wiki/Nuclear_weapon
http://en.wikipedia.org/wiki/Zero_Option
http://en.wikipedia.org/wiki/Nuclear_power

However, there is general consensus in the global community that the number and types of nuclear weapons needs to be reduced and further proliferation avoided if possible. There is less consensus on the use of nuclear energy, but general agreement on the need for:

1) More integrated strategies for monitoring and responding to the recruitment of trained nuclear scientists and engineers by suspicious parties, and against the purchase or acquisition of fissile materials, nuclear waste materials, nuclear know-how and technical expertise (Pakistani scientists in North Korea and Iran), non- nuclear components of a nuclear bomb or advanced delivery systems by such parties on the black market.

http://www.nci.org/nci-nt.htm

2) increased secret service surveillance and international cooperation in this field.

3) improvements in the security provided to and at nuclear plants.

4) better and more regular tests on the safety of nuclear facilities.

5) better and permanent arrangements for the recycling and/or storage of nuclear waste.

For source material about the dispute between the UN, US and Iran see:

https://en.wikipedia.org/wiki/United_States_withdrawal_from_the_Joint_Comprehensive_Plan_of_Action

https://www.aljazeera.com/news/2018/05/world-leaders-react-withdrawal-iranian-nuclear-deal-180508184130931.html

http://time.com/5270821/iran-nuclear-deal-trump-ayatollah-khameini-hassan-rouhani/

https://www.theguardian.com/world/2018/nov/05/why-europe-wants-to-sidestep-us-sanctions-over-iran-nuclear-might

https://www.armscontrol.org/blog/2018-12-05/europeans-advance-alternative-payment-system-iran-p41-iran-nuclear-deal-alert