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84-578: The National Nuclear Security Administration ( NNSA ) is a United States federal agency responsible for safeguarding national security through the military application of nuclear science . NNSA maintains and enhances the safety, security, and effectiveness of the U.S. nuclear weapons stockpile; works to reduce the global danger from weapons of mass destruction ; provides the United States Navy with safe and effective nuclear propulsion ; and responds to nuclear and radiological emergencies in

168-526: A classical system , rather than a quantum-mechanical one. In the resulting liquid-drop model , the nucleus has an energy that arises partly from surface tension and partly from electrical repulsion of the protons. The liquid-drop model is able to reproduce many features of nuclei, including the general trend of binding energy with respect to mass number, as well as the phenomenon of nuclear fission . Superimposed on this classical picture, however, are quantum-mechanical effects, which can be described using

252-493: A phase transition from normal nuclear matter to a new state, the quark–gluon plasma , in which the quarks mingle with one another, rather than being segregated in triplets as they are in neutrons and protons. Eighty elements have at least one stable isotope which is never observed to decay, amounting to a total of about 251 stable nuclides. However, thousands of isotopes have been characterized as unstable. These "radioisotopes" decay over time scales ranging from fractions of

336-450: A Polish physicist whose maiden name was Sklodowska, Pierre Curie , Ernest Rutherford and others. By the turn of the century, physicists had also discovered three types of radiation emanating from atoms, which they named alpha , beta , and gamma radiation. Experiments by Otto Hahn in 1911 and by James Chadwick in 1914 discovered that the beta decay spectrum was continuous rather than discrete. That is, electrons were ejected from

420-605: A collective ceiling of $ 4 billion among the five selected contractors. DTRA awarded BV the first BTRIC in Ukraine in 2008, which "is a vital part" of the CTR, entitled Biological Threat Reduction (BTR). The Implementing (Executive) Agents were three in number: the Ukraine Ministry of Health , Ukraine Academy of Agrarian Sciences and Ukraine State Committee for Veterinary Medicine . In July 2008 President Medvedev signed

504-408: A different number of protons. In alpha decay , which typically occurs in the heaviest nuclei, the radioactive element decays by emitting a helium nucleus (2 protons and 2 neutrons), giving another element, plus helium-4 . In many cases this process continues through several steps of this kind, including other types of decays (usually beta decay) until a stable element is formed. In gamma decay ,

588-408: A nucleus decays from an excited state into a lower energy state, by emitting a gamma ray . The element is not changed to another element in the process (no nuclear transmutation is involved). Other more exotic decays are possible (see the first main article). For example, in internal conversion decay, the energy from an excited nucleus may eject one of the inner orbital electrons from the atom, in

672-557: A plan to further reduce U.S. and Russian nuclear arsenals , which would further reduce the number of nuclear weapons in the world today. This plan was the result of the impending expiration of the Strategic Arms Reduction Treaty ( START I ). START was set to expire in December 2009. In October 2012 the second Putin administration declared that Russia would not extend the CTR agreement without changes in

756-518: A process which produces high speed electrons but is not beta decay and (unlike beta decay) does not transmute one element to another. In nuclear fusion , two low-mass nuclei come into very close contact with each other so that the strong force fuses them. It requires a large amount of energy for the strong or nuclear forces to overcome the electrical repulsion between the nuclei in order to fuse them; therefore nuclear fusion can only take place at very high temperatures or high pressures. When nuclei fuse,

840-488: A second to trillions of years. Plotted on a chart as a function of atomic and neutron numbers, the binding energy of the nuclides forms what is known as the valley of stability . Stable nuclides lie along the bottom of this energy valley, while increasingly unstable nuclides lie up the valley walls, that is, have weaker binding energy. The most stable nuclei fall within certain ranges or balances of composition of neutrons and protons: too few or too many neutrons (in relation to

924-513: A spin of ± + 1 ⁄ 2 . In the Rutherford model of nitrogen-14, 20 of the total 21 nuclear particles should have paired up to cancel each other's spin, and the final odd particle should have left the nucleus with a net spin of 1 ⁄ 2 . Rasetti discovered, however, that nitrogen-14 had a spin of 1. In 1932 Chadwick realized that radiation that had been observed by Walther Bothe , Herbert Becker , Irène and Frédéric Joliot-Curie

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1008-487: A variety of programs. Briefly, these include: The CTR program is authorized by Title 22 of the United States Code , chapter 68a. The FY 2007 CTR Annual Report to Congress provides a status update on the program as a whole and individual initiatives. It also details future planned endeavors in each area. The Nunn-Lugar Act was a major contributor to de-escalation of nuclear weapon arsenals. This program

1092-497: A very large amount of energy is released and the combined nucleus assumes a lower energy level. The binding energy per nucleon increases with mass number up to nickel -62. Stars like the Sun are powered by the fusion of four protons into a helium nucleus, two positrons , and two neutrinos . The uncontrolled fusion of hydrogen into helium is known as thermonuclear runaway. A frontier in current research at various institutions, for example

1176-481: A whole, including its electrons . Discoveries in nuclear physics have led to applications in many fields. This includes nuclear power , nuclear weapons , nuclear medicine and magnetic resonance imaging , industrial and agricultural isotopes, ion implantation in materials engineering , and radiocarbon dating in geology and archaeology . Such applications are studied in the field of nuclear engineering . Particle physics evolved out of nuclear physics and

1260-412: Is held together by the strong nuclear force, unless it is too large. Unstable nuclei may undergo alpha decay, in which they emit an energetic helium nucleus, or beta decay, in which they eject an electron (or positron ). After one of these decays the resultant nucleus may be left in an excited state, and in this case it decays to its ground state by emitting high-energy photons (gamma decay). The study of

1344-478: Is responsible for providing efficient nuclear propulsion plants to the United States Navy. It is also known as Naval Reactors . It conducts the design, development and operational support required to power all the U.S. Navy's aircraft carriers and nuclear submarines . The program consists of both civilian and military personnel who maintain, design, build, and manage the reactors. The following are

1428-464: Is the source of energy for nuclear power plants and fission-type nuclear bombs, such as those detonated in Hiroshima and Nagasaki , Japan, at the end of World War II . Heavy nuclei such as uranium and thorium may also undergo spontaneous fission , but they are much more likely to undergo decay by alpha decay. For a neutron-initiated chain reaction to occur, there must be a critical mass of

1512-475: The Joint European Torus (JET) and ITER , is the development of an economically viable method of using energy from a controlled fusion reaction. Nuclear fusion is the origin of the energy (including in the form of light and other electromagnetic radiation) produced by the core of all stars including our own Sun. Nuclear fission is the reverse process to fusion. For nuclei heavier than nickel-62

1596-545: The National Academy of Sciences Committee on International Security and Arms Control to discuss the next ten years regarding the CTR program. The committee found that the Cooperative, or "C", in CTR was found to be central in reducing threats through transparency and action further strengthening world relations while mitigating dangers to the U.S. Sustainable partnerships between new and existing countries under

1680-667: The Top500 list. Another important asset used to test the stockpile is the National Ignition Facility (NIF) at LLNL , a laser-based inertial confinement fusion research device. NIF achieved the first scientific breakeven controlled fusion experiment on December 5, 2022, with an energy gain factor of 1.5. Since then four additional ignition shots followed the December experiment: July 30, 2023; October 8, 2023; October 30, 2023; and February 12, 2024. The most recent experiment produced an estimated 5.2 MJ—more than doubling

1764-736: The Ural Mountains , the site is expected to destroy some 5,500 tons of chemical agents, including Sarin and VX . About one-third of the funding to build the plant, roughly $ 1 billion, was provided by CTR. Although the budget for the CTR program has been cut every year since the Obama administration began, the US still faces many issues when it comes to agreements with Russia in nuclear arms reduction. President Obama had his own ideas for nuclear threat reduction. He and Hillary Clinton tried to reset nuclear relations with Russia . This plan included

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1848-424: The electron by J. J. Thomson a year later was an indication that the atom had internal structure. At the beginning of the 20th century the accepted model of the atom was J. J. Thomson's "plum pudding" model in which the atom was a positively charged ball with smaller negatively charged electrons embedded inside it. In the years that followed, radioactivity was extensively investigated, notably by Marie Curie ,

1932-433: The nuclear shell model , developed in large part by Maria Goeppert Mayer and J. Hans D. Jensen . Nuclei with certain " magic " numbers of neutrons and protons are particularly stable, because their shells are filled. Other more complicated models for the nucleus have also been proposed, such as the interacting boson model , in which pairs of neutrons and protons interact as bosons . Ab initio methods try to solve

2016-465: The "heavier elements" (carbon, element number 6, and elements of greater atomic number ) that we see today, were created inside stars during a series of fusion stages, such as the proton–proton chain , the CNO cycle and the triple-alpha process . Progressively heavier elements are created during the evolution of a star. Energy is only released in fusion processes involving smaller atoms than iron because

2100-660: The 9/11 terrorist attacks, knowledge regarding Pakistani nuclear weaponry and nuclear scientists was unclear making it a strong candidate from American political leaders for Nunn-Lugar. Border crossing between Pakistan and Afghanistan militants made U.S. officials uneasy, this alongside the allegations of nuclear arms smuggling caused further talk of Nunn-Lugar program expansion in 2011. Senator Richard Lugar has expressed his concern regarding Pakistani nuclear weapons of mass destruction along with concerns over potential pathogenic and infectious disease security. Lugar also stated that if an outbreak occurs, if Pakistan accepts transparency with

2184-641: The CTR Program was originally "to secure and dismantle weapons of mass destruction and their associated infrastructure in former Soviet Union states." As the peace dividend grew old, an alternative 2009 explanation of the program was "to secure and dismantle weapons of mass destruction in states of the former Soviet Union and beyond". The CTR program funds have been disbursed since 1997 by the Defense Threat Reduction Agency (DTRA). CTR provided funding and expertise for states in

2268-603: The CTR does more good than harm which has led to funding expansion. This expansion of the program is displayed in the 1997 Defense Authorization Act whose purposed served in securing chemical and biological weapon materials. In contrast, opponents say that the US funding is going to other Russian programs. Going into the 21st century, efforts now have an expanded focus including a more generalized nuclear nonproliferation motive. In 2003 Libya decided upon giving up on their nuclear weapons program. Funding from Nunn-Lugar allowed for secure transportation of nuclear materials from Libya to

2352-669: The CTR initiative. Weapons deactivated and destroyed under this program include: Other milestone results include: One Nunn–Lugar site, Pavlograd , Ukraine, dedicated itself beginning in June 2004 to the decommissioning of nuclear missiles without burning their solid rocket fuel , thus preventing dioxins from threatening the local environment and human population. The Pavlograd missile factory PMZ has been converted to an advanced astronautics "Space Clipper" program. Other countries are finding ways to produce, test, and acquire weapons of mass destruction. In an attempt to regulate WMD globally,

2436-632: The CTR program, the U.S. will be able to provide aid and establish systems to combat an outbreak. Subsequent programs have built on the CTR, including the Proliferation Security Initiative , initially launched by President Bush in cooperation with Poland in 2003, and built on by multilateral efforts and then by President Obama. In 2008 the DTRA awarded Black & Veatch the first of its Biological Threat Reduction Integrating Contracts (BTRIC). The five-year IDIQ contract has

2520-726: The Nunn–Lugar Cooperative Threat Reduction has stepped outside of the former Soviet Union states. 2003 marked an important year for CTR expansion as the initiative was accepted by congress allowing the spread to countries not included within the prior Soviet Union. The Nunn-Lugar Expansion Act under the 108th congress granted up to $ 50 million to be used outside the former Soviet Union which focused primarily on Albania, North Korea, Iraq, and Libya. Over time Nunn-Lugar has received many supporters and also many critics. Continuation and expansion has been up for debate since its initial formation in 1991. Proponents argue that

2604-485: The Obama administration's second term." As far as reducing nuclear weapons in other countries, besides Ukraine, there is more of a chance of an agreement. This idea is explained in "countering nuclear weapons proliferation to states and to nonstate actors, the prospects are somewhat better, given mutual Russian and U.S. concerns in that area". There are still many agreements that have been proposed that can be passed between

National Nuclear Security Administration - Misplaced Pages Continue

2688-558: The Office of Materials Management and Minimization is divided into three subprograms: Conversion, Nuclear Materials Removal, and Material Disposition. Through this office and its predecessors, NNSA has successfully led the recovery efforts of nuclear materials from dozens of countries. Since 1996, the Department of Energy/NNSA has disposed of enough material to produce more than 325 nuclear weapons. For example, in 2017, it removed all

2772-772: The Super Bowl. NNSA provides expertise, tools and technically informed policy recommendations to advance U.S. nuclear counterterrorism and counterproliferation objectives. It is responsible for understanding nuclear threat devices and foreign activities that cause proliferation concerns. To do this, members of the counterproliferation office confer with international counterparts on nuclear security and counterterrorism; conduct scientific research to characterize, detect and defeat nuclear threat devices; develop and conduct WMD counterterrorism exercises; and promote nuclear information security policy and practices. NNSA's Nuclear Propulsion Program – working with Naval Nuclear Laboratories –

2856-651: The US and Russia as far as nuclear weapons and the control and elimination of them are concerned. As time progresses, the threat of nuclear weapons and the money needed to spend on the elimination of them diminishes. The CTR program has faced many budget cuts since its beginning in 1986 because the program was, as opined by one observer, "created to deal with yesterday's strategic weapons and yesterday's threats have largely diminished". In January 2015 Russian Federation representatives told their US counterparts that Russia would no longer accept US assistance in securing stored weapons-grade nuclear material but said they would continue

2940-705: The United States and abroad. Established by the United States Congress in 2000, NNSA is a semiautonomous agency within the United States Department of Energy . The current Administrator is Jill Hruby . The National Nuclear Security Administration was created by Congressional action in 1999, in the wake of the Wen Ho Lee spy scandal and other allegations that lax administration by the Department of Energy had resulted in

3024-900: The United States of America and the Russian Federation Concerning the Safe and Secure Transportation, Storage and Destruction of Weapons and the Prevention of Weapons Proliferation , commonly known as the Nunn-Lugar Cooperative Threat Reduction Umbrella Agreement that expires today. This new bilateral framework authorizes the United States and the Russian Federation to work in several areas of nonproliferation collaboration, including protecting, controlling, and accounting for nuclear materials." Under

3108-576: The United States. Albania had possession of 16 tons of chemical weapons which were disclosed and disposed of through the Nunn-Lugar program. Nunn-Lugar funds in the year 2004, under the Bush presidency, were provided to eliminate all chemical weapons held within Albania which amounted to roughly $ 38.5 million. After just 3 years Albania no longer possessed chemical weapons of mass destruction. After

3192-425: The aid of the elimination of nuclear weapons in this country. The Nunn-Lugar Act played a major role in a huge decrease in the quantity of nuclear weapons that had been stockpiled during the nuclear escalation period. Another important contribution was seen when the US sent storage containers to Russia to store fissionable material under Russian control. The US provided "10,000 fissile material storage containers by

3276-499: The atom with a continuous range of energies, rather than the discrete amounts of energy that were observed in gamma and alpha decays. This was a problem for nuclear physics at the time, because it seemed to indicate that energy was not conserved in these decays. The 1903 Nobel Prize in Physics was awarded jointly to Becquerel, for his discovery and to Marie and Pierre Curie for their subsequent research into radioactivity. Rutherford

3360-403: The atom, in which the atom had a very small, very dense nucleus containing most of its mass, and consisting of heavy positively charged particles with embedded electrons in order to balance out the charge (since the neutron was unknown). As an example, in this model (which is not the modern one) nitrogen-14 consisted of a nucleus with 14 protons and 7 electrons (21 total particles) and the nucleus

3444-538: The binding energy per nucleon peaks around iron (56 nucleons). Since the creation of heavier nuclei by fusion requires energy, nature resorts to the process of neutron capture. Neutrons (due to their lack of charge) are readily absorbed by a nucleus. The heavy elements are created by either a slow neutron capture process (the so-called s -process ) or the rapid , or r -process . The s process occurs in thermally pulsing stars (called AGB, or asymptotic giant branch stars) and takes hundreds to thousands of years to reach

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3528-486: The binding energy per nucleon decreases with the mass number. It is therefore possible for energy to be released if a heavy nucleus breaks apart into two lighter ones. The process of alpha decay is in essence a special type of spontaneous nuclear fission . It is a highly asymmetrical fission because the four particles which make up the alpha particle are especially tightly bound to each other, making production of this nucleus in fission particularly likely. From several of

3612-785: The collapse of the Soviet Union appeared imminent, the United States and their NATO allies grew concerned of the risk of nuclear weapons held in the Soviet republics falling into enemy hands. The Cooperative Threat Reduction ( CTR ) program was initiated by the Nunn–Lugar Act (really the Soviet Nuclear Threat Reduction Act of 1991 ), which was authored and cosponsored by Sens . Sam Nunn ( D - GA ) and Richard Lugar ( R - IN ). The purpose of

3696-553: The content of Proca's equations for developing a theory of the atomic nuclei in Nuclear Physics. In 1935 Hideki Yukawa proposed the first significant theory of the strong force to explain how the nucleus holds together. In the Yukawa interaction a virtual particle , later called a meson , mediated a force between all nucleons, including protons and neutrons. This force explained why nuclei did not disintegrate under

3780-750: The disarmament of nuclear warheads in many counties. The Nunn-Lugar program eliminated former strategic weapons outside of Russia. This was most evident in the removal of these weapons in Ukraine, after the Budapest Memorandum on Security Assurances . There were many countries that had Soviet nuclear weapons. Two others included Belarus and Kazakhstan. Nunn-Lugar helped Russia to move the nuclear arsenals in these countries to Russia or to dismember these weapons in these countries. The US sent "nearly 700 emergency response items to help guarantee safe and secure transportation of nuclear weapons" to Belarus for

3864-466: The discovery that the nucleus itself was composed of smaller constituents, the nucleons . In 1906, Ernest Rutherford published "Retardation of the α Particle from Radium in passing through matter." Hans Geiger expanded on this work in a communication to the Royal Society with experiments he and Rutherford had done, passing alpha particles through air, aluminum foil and gold leaf. More work

3948-660: The effectiveness of the American nuclear weapons stockpile include the Dual-Axis Radiographic Hydrodynamic Test Facility (DARHT) at Los Alamos National Laboratory, the Contained Firing Facility at Lawrence Livermore National Laboratory and the Z Machine at Sandia National Laboratories. NNSA also uses powerful supercomputers to run simulations and validate experimental data; these computers often appear on

4032-399: The elements of the program: NNSA has several offices that support its primary missions. Among them are: NNSA's Office of Emergency Operations has the obligation of responding to emergencies on behalf of the entire Department of Energy. Its high level of alertness allows the United States to respond to incidents in a rapid manner. NNSA's Office of Defense Nuclear Security is responsible for

4116-455: The end of 1995 and a total of nearly 33,000 containers by early 1997". These containers aided in Russia's ability to store nuclear material from dismantled warheads. Another contribution from the US to Russia was "75 million dollars to help Russia build a new fissile material storage facility at Chelyabinsk for plutonium "pits" from dismantled warheads". The Nuclear Threat Reduction program

4200-426: The equivalence of mass and energy to within 1% as of 1934. Alexandru Proca was the first to develop and report the massive vector boson field equations and a theory of the mesonic field of nuclear forces . Proca's equations were known to Wolfgang Pauli who mentioned the equations in his Nobel address, and they were also known to Yukawa, Wentzel, Taketani, Sakata, Kemmer, Heitler, and Fröhlich who appreciated

4284-404: The existing nuclear deterrent through the use of science experiments, engineering audits and high-tech simulations at its three national laboratories : Los Alamos National Laboratory , Lawrence Livermore National Laboratory , and Sandia National Laboratories . It also creates new weapons programs as required by the United States Department of Defense . NNSA assets used to maintain and ensure

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4368-412: The foil with their trajectories being at most slightly bent. But Rutherford instructed his team to look for something that shocked him to observe: a few particles were scattered through large angles, even completely backwards in some cases. He likened it to firing a bullet at tissue paper and having it bounce off. The discovery, with Rutherford's analysis of the data in 1911, led to the Rutherford model of

4452-563: The former Soviet Union (including Russia , Ukraine , Georgia , Azerbaijan , Belarus , Uzbekistan , and Kazakhstan ) to decommission nuclear , biological , and chemical weapon stockpiles, as agreed by the Soviet Union under disarmament treaties such as SALT I . This funding totaled $ 400 million a year for a total of four years. This $ 400 million was given to CTR-related defense programs. The Departments of Defense (DOD), Energy (DOE), state, and commerce were subject to distribute

4536-458: The funding. After the nuclear warheads were removed from their delivery vehicles by the post-Soviet successor militaries, Nunn-Lugar assistance provided equipment and supplies to destroy the missiles on which the warheads had been mounted, as well as the silos which had contained the missiles. The warheads themselves were then shipped to and destroyed in Russia, with the highly enriched uranium contained within made into commercial reactor fuel, which

4620-766: The heat emanating from the Earth's core results from radioactive decay. However, it is not known if any of this results from fission chain reactions. According to the theory, as the Universe cooled after the Big Bang it eventually became possible for common subatomic particles as we know them (neutrons, protons and electrons) to exist. The most common particles created in the Big Bang which are still easily observable to us today were protons and electrons (in equal numbers). The protons would eventually form hydrogen atoms. Almost all

4704-525: The heaviest elements of lead and bismuth. The r -process is thought to occur in supernova explosions , which provide the necessary conditions of high temperature, high neutron flux and ejected matter. These stellar conditions make the successive neutron captures very fast, involving very neutron-rich species which then beta-decay to heavier elements, especially at the so-called waiting points that correspond to more stable nuclides with closed neutron shells (magic numbers). Cooperative Threat Reduction As

4788-439: The heaviest nuclei whose fission produces free neutrons, and which also easily absorb neutrons to initiate fission, a self-igniting type of neutron-initiated fission can be obtained, in a chain reaction . Chain reactions were known in chemistry before physics, and in fact many familiar processes like fires and chemical explosions are chemical chain reactions. The fission or "nuclear" chain-reaction , using fission-produced neutrons,

4872-618: The highly enriched uranium from Ghana and repatriated it to China. The Ghanaian reactor now uses low-enriched uranium. NNSA's Office of Counterterrorism and Counterproliferation focuses on: The office oversees the capabilities of the Nuclear Emergency Support Team . NNSA deploys response teams dozens of times each year, usually to check for radioactive materials. Missions assuage safety concerns, support other agencies, and bolster law enforcement capabilities at large public events such as presidential inaugurations and

4956-417: The influence of proton repulsion, and it also gave an explanation of why the attractive strong force had a more limited range than the electromagnetic repulsion between protons. Later, the discovery of the pi meson showed it to have the properties of Yukawa's particle. With Yukawa's papers, the modern model of the atom was complete. The center of the atom contains a tight ball of neutrons and protons, which

5040-485: The input energy of 2.2 MJ. The Office of Secure Transportation provides safe and secure transportation of nuclear weapons and components and special nuclear materials, and conducts other missions supporting national security. OST shipments are moved in specially designed equipment and escorted by armed and specially trained federal agents . NNSA's Office of Defense Nuclear Nonproliferation works with international partners, federal agencies, U.S. national laboratories, and

5124-467: The loss of U.S. nuclear secrets to China. Originally proposed to be an independent agency, it was instead chartered as a semiautonomous agency within the Department of Energy to be headed by an administrator reporting to the Secretary of Energy. The first Under Secretary for Nuclear Security and NNSA administrator appointed was Air Force General (and CIA Deputy Director) John A. Gordon . In 2006, it

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5208-418: The neutrons created in the Big Bang were absorbed into helium-4 in the first three minutes after the Big Bang, and this helium accounts for most of the helium in the universe today (see Big Bang nucleosynthesis ). Some relatively small quantities of elements beyond helium (lithium, beryllium, and perhaps some boron) were created in the Big Bang, as the protons and neutrons collided with each other, but all of

5292-600: The new framework, Russia assumed the costs and the completion without further US assistance of two areas of bilateral CTR cooperation previously covered by the CTR framework: ballistic missile elimination and chemical weapons destruction. In Obama's second term , work on nuclear threat reduction was said to be more bleak because of the Annexation of Crimea by the Russian Federation . Arms Control Today opined that "the crisis in Ukraine probably has ruined prospects for another formal Russian-U.S. arms control agreement during

5376-660: The nuclear many-body problem from the ground up, starting from the nucleons and their interactions. Much of current research in nuclear physics relates to the study of nuclei under extreme conditions such as high spin and excitation energy. Nuclei may also have extreme shapes (similar to that of Rugby balls or even pears ) or extreme neutron-to-proton ratios. Experimenters can create such nuclei using artificially induced fusion or nucleon transfer reactions, employing ion beams from an accelerator . Beams with even higher energies can be used to create nuclei at very high temperatures, and there are signs that these experiments have produced

5460-409: The number of protons) will cause it to decay. For example, in beta decay , a nitrogen -16 atom (7 protons, 9 neutrons) is converted to an oxygen -16 atom (8 protons, 8 neutrons) within a few seconds of being created. In this decay a neutron in the nitrogen nucleus is converted by the weak interaction into a proton, an electron and an antineutrino . The element is transmuted to another element, with

5544-404: The overall security of facilities housing nuclear weapons as well as the components and materials required to develop them -- this includes oversight of Federal Protective Forces at NNSA's labs, plants, and sites. The office also safeguards personnel and produces threat assessments. Nuclear physics Nuclear physics should not be confused with atomic physics , which studies the atom as

5628-662: The private sector to discover, protect, and or dispose of radiological and nuclear materials. The office strives to: The agency created the Global Threat Reduction Initiative in 2004 to expand efforts similar to the Cooperative Threat Reduction program beyond the former Soviet Union. In 2016, GTRI was renamed the Office of Materials Management and Minimization, and continues the efforts of supporting reactor conversions, fuel returns, and LEU fuel development. The work of

5712-574: The problem of the spin of nitrogen-14, as the one unpaired proton and one unpaired neutron in this model each contributed a spin of 1 ⁄ 2 in the same direction, giving a final total spin of 1. With the discovery of the neutron, scientists could at last calculate what fraction of binding energy each nucleus had, by comparing the nuclear mass with that of the protons and neutrons which composed it. Differences between nuclear masses were calculated in this way. When nuclear reactions were measured, these were found to agree with Einstein's calculation of

5796-496: The program on their own. Joint security work at numerous Russian sites and facilities was halted on 1 January 2015. In December 2014, the program awarded a $ 4 million contract to MRIGlobal to "configure, equip, deploy and staff two quick response mobile laboratory systems (MLS) to support the ongoing Ebola outbreak in West Africa ." The labs were deployed to Sierra Leone . In 2018, David Franz and Libby Turpen co-chaired

5880-538: The ratification law to cooperate in "the elimination of reduced strategic offensive weapons, improving the safety of storing and transporting nuclear weapons, improving the physical protection of nuclear materials and the destruction of chemical weapons," retroactive to the signature of the protocol on 16 June 2006 for a term of seven years. In May 2009, Russia announced the opening of a major facility to decommission its chemical weapons reserves. Built near vast reserves of ex-Soviet weaponry at Shchuchye, Kurgan Oblast , in

5964-498: The relevant isotope present in a certain space under certain conditions. The conditions for the smallest critical mass require the conservation of the emitted neutrons and also their slowing or moderation so that there is a greater cross-section or probability of them initiating another fission. In two regions of Oklo , Gabon, Africa, natural nuclear fission reactors were active over 1.5 billion years ago. Measurements of natural neutrino emission have demonstrated that around half of

6048-486: The strong and weak nuclear forces (the latter explained by Enrico Fermi via Fermi's interaction in 1934) led physicists to collide nuclei and electrons at ever higher energies. This research became the science of particle physics , the crown jewel of which is the standard model of particle physics , which describes the strong, weak, and electromagnetic forces . A heavy nucleus can contain hundreds of nucleons . This means that with some approximation it can be treated as

6132-488: The text. On 14 June 2013 the US and Russia signed a new bilateral framework on cooperative threat reduction intended to supersede the first CTR. The new agreement was intended to reinforce the longstanding partnership on nonproliferation between these two nations and their activities in Russia and the Former Soviet Republics (FSR). "This new framework builds upon the success of the 1992 Agreement between

6216-471: The two fields are typically taught in close association. Nuclear astrophysics , the application of nuclear physics to astrophysics , is crucial in explaining the inner workings of stars and the origin of the chemical elements . The history of nuclear physics as a discipline distinct from atomic physics , starts with the discovery of radioactivity by Henri Becquerel in 1896, made while investigating phosphorescence in uranium salts. The discovery of

6300-489: Was a particularly remarkable development since at that time fusion and thermonuclear energy, and even that stars are largely composed of hydrogen (see metallicity ), had not yet been discovered. The Rutherford model worked quite well until studies of nuclear spin were carried out by Franco Rasetti at the California Institute of Technology in 1929. By 1925 it was known that protons and electrons each had

6384-439: Was actually due to a neutral particle of about the same mass as the proton, that he called the neutron (following a suggestion from Rutherford about the need for such a particle). In the same year Dmitri Ivanenko suggested that there were no electrons in the nucleus — only protons and neutrons — and that neutrons were spin 1 ⁄ 2 particles, which explained the mass not due to protons. The neutron spin immediately solved

6468-517: Was awarded the Nobel Prize in Chemistry in 1908 for his "investigations into the disintegration of the elements and the chemistry of radioactive substances". In 1905, Albert Einstein formulated the idea of mass–energy equivalence . While the work on radioactivity by Becquerel and Marie Curie predates this, an explanation of the source of the energy of radioactivity would have to wait for

6552-491: Was confirmed that NNSA employee information had been hacked. A report criticized the response. NNSA's Administrator took responsibility. NNSA has the following missions with regard to national security: One of NNSA's primary missions is to maintain the safety, security and effectiveness of the United States' nuclear weapons stockpile. After the Cold War , the U.S. voluntarily ended underground nuclear testing . NNSA maintains

6636-569: Was not just used to remove everything fissionable from Russia; it also included ideas for safe storage and transportation of fissionable material in Russia built up during the Cold War. Ukraine and Kazakhstan are nuclear weapons free because of this program. Under CTR, the U.S. and recipient states have made considerable advancements in global security against the threat of WMD. By 1997 all strategic Soviet nuclear weapons were removed from Belarus, Kazakhstan, and Ukraine marking an important landmark in

6720-466: Was performed during 1909, at the University of Manchester . Ernest Rutherford's assistant, Professor Johannes "Hans" Geiger, and an undergraduate, Marsden, performed an experiment in which Geiger and Marsden under Rutherford's supervision fired alpha particles ( helium 4 nuclei ) at a thin film of gold foil. The plum pudding model had predicted that the alpha particles should come out of

6804-470: Was published in 1909 by Geiger and Ernest Marsden , and further greatly expanded work was published in 1910 by Geiger . In 1911–1912 Rutherford went before the Royal Society to explain the experiments and propound the new theory of the atomic nucleus as we now understand it. Published in 1909, with the eventual classical analysis by Rutherford published May 1911, the key preemptive experiment

6888-480: Was purchased by the United States under a separate program. In recent years, the CTR program has expanded its mission from securing WMDs at the root source to protecting against WMD "on the move", by enhancing land and maritime border security in the former Soviet Union. According to the CTR website in 2007, CTR had four key objectives: These objectives were compartmentalized into three program areas which include: These areas were then pursued and achieved through

6972-499: Was surrounded by 7 more orbiting electrons. Around 1920, Arthur Eddington anticipated the discovery and mechanism of nuclear fusion processes in stars , in his paper The Internal Constitution of the Stars . At that time, the source of stellar energy was a complete mystery; Eddington correctly speculated that the source was fusion of hydrogen into helium, liberating enormous energy according to Einstein's equation E = mc . This

7056-461: Was used for "the transportation, storage, safeguarding and destruction of nuclear and other weapons in the Soviet Union… and to assist in the prevention of weapons proliferation". One contribution by the Nunn-Lugar program has been the "delivery of equipment to accelerate the dismantlement of strategic nuclear delivery vehicles" to the Soviet Union. This program made important contributions in

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