Startup neutron source

Neutron sources

Startup neutron source is a neutron source used for stable and reliable initiation of nuclear chain reaction in nuclear reactors, when they are loaded with fresh nuclear fuel, whose neutron flux from spontaneous fission is insufficient for a reliable startup, or after prolonged shutdown periods. Neutron sources ensure a constant minimal population of neutrons in the reactor core, sufficient for a smooth startup. Without them, the reactor could suffer fast power excursions during startup from state with too few self-generated neutrons (new core or after extended shutdown). The startup sources are typically inserted in regularly spaced positions inside the reactor core, in place of some of the fuel rods. The sources are important for safe reactor startup. The spontaneous fission and cosmic rays serve as weak neutron sources, but these are too weak for the reactor instrumentation to detect; relying on them could lead to a "blind" start, which is a potentially unsafe condition. The sources are therefore positioned so the neutron flux they produce is always detectable by the reactor monitoring instruments. When the reactor is in shutdown state, the neutron sources serve to provide signals for neutron detectors monitoring the reactor, to ensure they are operable. The equilibrium level of neutron flux in a subcritical reactor is dependent on the neutron source strength; a certain minimum level of source activity therefore has to be ensured in order to maintain control over the reactor when in strongly subcritical state, namely during startups. The sources can be of two types: * Primary sources, used for startup of a fresh reactor core; conventional neutron sources are used. The primary sources are removed from the reactor after the first fuel campaign, usually after few months, as neutron capture resulting from the thermal neutron flux in an operating reactor changes the composition of the isotopes used, and thus reduces their useful lifetime as neutron sources. * Californium-252 (spontaneous fission) * Plutonium-238 & beryllium, (α,n) reaction * americium-241 & beryllium, (α,n) reaction * polonium-210 & beryllium, (α,n) reaction * radium-226 & beryllium, (α,n) reaction When plutonium-238/beryllium primary sources are utilized, they can be either affixed to control rods which are removed from the reactor when it is powered, or clad in a cadmium alloy, which is opaque to thermal neutrons (reducing transmutation of the plutonium-238 by neutron capture) but transparent to fast neutrons produced by the source. * Secondary sources, originally inert, become radioactive and neutron-producing only after neutron activation in the reactor. Due to this, they tend to be less expensive. Exposure to thermal neutrons also serves to maintain the source activity (the radioactive isotopes are both burned and generated in neutron flux). * Sb-Be photoneutron source; antimony becomes radioactive in the reactor and its strong gamma emissions (1.7 MeV for 124Sb) interact with beryllium-9 by an (γ,n) reaction and provide photoneutrons. In a PWR reactor one neutron source rod contains 160 grams of antimony, and stays in the reactor for 5–7 years. The sources are often constructed as an antimony rod surrounded by beryllium layer and clad in stainless steel. Antimony-beryllium alloy can be also used. The chain reaction in the first critical reactor, CP-1, was initiated by a radium-beryllium neutron source. Similarly, in modern reactors (after startup), delayed neutron emission from fission products suffices to sustain the amplification reaction while yielding controllable growth times. In comparison, a bomb is based on immediate neutrons and grows exponentially in nanoseconds. (Wikipedia).

Fission Reactor

Watch more videos on http://www.brightstorm.com/science/physics SUBSCRIBE FOR All OUR VIDEOS! https://www.youtube.com/subscription_center?add_user=brightstorm2 VISIT BRIGHTSTORM.com FOR TONS OF VIDEO TUTORIALS AND OTHER FEATURES! http://www.brightstorm.com/ LET'S CONNECT! Facebook ► htt

From playlist Physics

First Ever Neutron Star Collision Progenitor Found in the Milky Way

Get a Wonderful Person Tee: https://teespring.com/stores/whatdamath More cool designs are on Amazon: https://amzn.to/3wDGy2i Alternatively, PayPal donations can be sent here: http://paypal.me/whatdamath Hello and welcome! My name is Anton and in this video, we will talk about Links: http

From playlist Neutron Stars

What is light?

Subscribe to our YouTube Channel for all the latest from World Science U. Visit our Website: http://www.worldscienceu.com/ Like us on Facebook: https://www.facebook.com/worldscienceu Follow us on Twitter: https://twitter.com/worldscienceu

From playlist Science Unplugged: Physics

Astronomy - Ch. 22: Neutron Star (1 of 17) What is a Neutron Star?

Visit http://ilectureonline.com for more math and science lectures! To donate: http://www.ilectureonline.com/donate https://www.patreon.com/user?u=3236071 We will learn a neutron star is the remnant of the collapse of he core of a super massive star (greater than 8 times the of our Sun).

From playlist THE "WHAT IS" PLAYLIST

Teach Astronomy - Fission as an Energy Source

http://www.teachastronomy.com/ Fission is such an efficient energy source that humans have long tried to harness it. A massive atomic nucleus can be split by a neutron. Since the decay of a massive nucleus can also release a neutron, this raises the possibility of a chain reaction where

From playlist 13. Particle Physics and the Sun

How are neutrinos produced?

From playlist Science Unplugged: Neutrinos

What are Quarks?

From playlist Science Unplugged: Particle Physics

We Finally Detected a Collision Between a Black Hole and a Neutron Star

You can buy Universe Sandbox 2 game here: http://amzn.to/2yJqwU6 Hello and welcome! My name is Anton and in this video, we will talk about a new discovery of a collision between a neutron star and a black hole. Grace DB: https://gracedb.ligo.org/superevents/S190814bv/ Support this channe

From playlist Blackholes

Technology and Cosmic Frontiers by Kip Thorne and Rana Adhikari

Public Lectures Technology & Cosmic Frontiers Speaker: Kip S. Thorne (Richard P. Feynman Professor of Theoretical Physics (Emeritus), Caltech Nobel Laureate in Physics, 2017) and Rana Adhikari (Professor of Physics, Caltech) Date: 19 August 2021, 19:00 to 20:00 Venue: Online A lectu

From playlist Public Lectures

Californium (new) - Periodic Table of Videos

An extensive video about Californium, which reportedly costs up to $27m per gram. We go to where it's made in Oak Ridge, Tennessee. More links and info in full description ↓↓↓ This video features Professor Martyn Poliakoff at the University of Nottingham. And Julie Ezold and Rose Boll at

From playlist All Chemical Elements in Order - Periodic Videos

7. Q-Equation Continued and Examples

MIT 22.01 Introduction to Nuclear Engineering and Ionizing Radiation, Fall 2016 Instructor: Michael Short View the complete course: https://ocw.mit.edu/22-01F16 YouTube Playlist: https://www.youtube.com/playlist?list=PLUl4u3cNGP61FVzAxBP09w2FMQgknTOqu One simplified Q-equation is given in

From playlist MIT 22.01 Introduction to Nuclear Engineering and Ionizing Radiation, Fall 2016

Forget Small ... What About Micro Nuclear Energy?

Revisiting Small Modular Reactors - The Future of Nuclear Energy? Get Surfshark VPN at https://surfshark.deals/undecided and enter promo code UNDECIDED for 83% off and 3 extra months for free! Although nuclear energy is reliable and a sustainable energy source, the nuclear energy debate ra

From playlist Revisiting

OpenStack On Ales 2013 - Software-Defined Networking with OpenFlow

By Tim Miller OpenStack networking supports several pluggable backends. Perhaps the most flexible and intriguing of these is the OpenVSwitch plugin, which is built atop the OpenFlow protocol. This talk describes the low-level details of the OpenFlow protocol, how it is implemented in both

From playlist OpenStack On Ales 2013

O'Reilly Webcast: Nuclear Energy - Future Directions

In the United Stated nuclear energy currently provides 75% of all non-fossil electricity generation. Greatly improved performance of nuclear power plants over the last 20 years has resulted in very high operating reliability, leading to plans for construction of new reactors in the United

From playlist O'Reilly Webcasts

Physics 50 E&M Radiation (3 of 33) What are sources of E&M Radiation

Visit http://ilectureonline.com for more math and science lectures! In this video I will give examples of sources of E&M radiation (satellite dishes, radio towers, light-bulbs...). Next video in series: http://youtu.be/SIQMcKD-hhg

From playlist PHYSICS 50 ELECTROMAGNETIC RADIATION

NOVA Now Universe Revealed Podcast Episode I Can We Recreate the Power of Stars Down on Earth?

Subscribe for free to get all episodes of NOVA Now on Apple Podcasts at https://apple.co/2U5GyYp The process that powers our sun was still a mystery about 100 years ago. Bit by bit, scientists have worked out that the fusion of hydrogen at a star’s core can generate enough power to keep i

From playlist NOVA Now Podcast

The Whole of AQA GCSE Physics Paper 1 | 25th May 2023

Covers in detail all the content needed for Combined and Separate science exams and both higher and foundation level. 2023 Predicted Exam Papers for GCSE and A-Level Biology, Chemistry, Physics, and Maths Revision Essential! https://www.primrosekitten.com/collections/predicted-papers FREE

From playlist Ultimate AQA GCSE Revision Playlist. For combined and separate science (Biology, Chemistry and Physics)

Putting the sun in a bottle: the path to delivering sustainable fusion power | The Royal Society

The imperative to address climate change is only escalating. Nuclear fusion – the process that powers the Sun – offers the potential for carbon-free, effectively limitless, continuous electricity, if only it can be harnessed here on Earth. The Royal Society Kavli Medal and Lecture 2019 gi

From playlist Popular talks and lectures

Discrete and Continuous Growth

We create simple models for discrete and continuous growth, and discuss the relationships between them.

From playlist Mathematical Physics I Uploads

31. Frontiers in Nuclear Medicine, Where One Finds Ionizing Radiation (Background and Other Sources)

From playlist MIT 22.01 Introduction to Nuclear Engineering and Ionizing Radiation, Fall 2016

Startup neutron source

Related pages