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Simulation of polyethylene-moderated plutonium neutron multiplicity measurements - دانلود فایل



دانلود فایل Simulation of polyethylene-moderated plutonium neutron multiplicity measurements

دانلود فایل Simulation of polyethylene-moderated plutonium neutron multiplicity measurements Neutron multiplicity measurements are a useful technique for the characterization of special nuclear
material. This technique relies on the detection of correlated neutrons from fission events. As correlated
events are detected it is possible to determine the neutron multiplicity distribution for the sample. This
distribution is useful for identifying the material and estimating the mass. This work focuses on the
ability of the Monte Carlo code MCNP-PoliMi to simulate measured distributions. The experiment used
as the basis of comparison consisted of a 4.5 kg plutonium metal sphere surrounded by up to 6 in. of
polyethylene. A bank of 15 (3 He) detectors was used to detect the correlated neutron events. MCNP-
PoliMi was used to simulate the particle transport and a post-processing algorithm was developed to
apply detector deadtime effects and to determine the neutron multiplicity distributions. These
simulated distributions were then compared to the measured results. The simulation provided an
adequate estimation of the measured data. However, we observed a systematic over-prediction in both
the mean and the variance of the measured distribution.


Monte Carlo


MCNP-PoliMi


Neutron multiplicity


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Patent US8884212 - Neutron multiplicity counting - Google Patents

11 Nov 2014 ... For each multiplicity category, the number of trigger pulses assigned thereto is ...
the quantity of fissile material such as, e.g. uranium (U), plutonium (Pu), .... “
Measurement variances in thermal neutron coincidence counting,” ..... Due to the
random path of each neutron in the polyethylene moderator 12, the ...

See Document - NSSPI - Texas A&M University

measurements and analyzing their neutron multiplicity response. ... neutrons
through neutron capture via 42 3He tubes embedded in polyethylene (which is
used for moderating, or slowing down, neutrons to increase detection probability)
. ... through measurements of known standards, computer simulations, or singles,
...

design of a neutron spectrometer and simulations of neutron ... - K-REx

polyethylene moderator to identify sources based on energy spectrum. Sources
are iden- ... plutonium sphere with various reflector thicknesses were simulated.
.... 5 Simulations of Neutron Multiplicity Measurements with Perturbations to.

Development of a Neutron Coincidence Counter for the Advanced ...

The multiplicity and (α, n) neutron rate of each nuclear material were estimated
using the MCNPX, SOURCES, and ORIGEN-S codes. From the simulation results
, it is clear that nuclear material ... The measured ... nium and plutonium in spent
fuel, containers, or simi- .... 3He tubes in the high-density polyethylene moderator
,.

8-cm thick borated polyethylene neutron moderator and... - Figure ...

See figure: 'Figure 33: 8-cm thick borated polyethylene neutron moderator and ...
plutonium metal sphere : subcritical neutron and gamma measurements. ... was
also measured with the gross neutron counter and neutron multiplicity counter
removed ... The simulation of the plutonium sphere measurement used two 12.7-
cm ...

View Article

that could account for the overprediction in the simulation of the plutonium sphere
. ..... Dimensions of the neutron multiplicity counter polyethylene moderator.

MCNPX-PoliMi simulation capacity using thermal neutron cross ...

neutron multiplicity measurements are useful to determine plutonium mass which
may be used as a warhead ... Thermal neutron cross-sections for the moderating
material .... D. Sprevak and J.U. Koppel, Neutron Scattering by Polyethylene,.

Mobile High Efficiency Multiplicity Counter for Uranium Measurements

Hexagonal Neutron Multiplicity Counter (HNMC), shown in ... third ring, the holes
for the tubes were drilled into the polyethylene moderator blocks to facilitate
future ... actual plutonium or uranium samples. .... To simulate the proposed
operation of the system, 3 Am(Li) sources were selected from Canberra's
inventory. The.

Total Plutonium Content Determination with the Differential ... - INMM

Total Plutonium Content Determination in Pressurized-Water Reactor Spent Fuel
... means of high fidelity neutron transport simulations the ability of the DDSI ...
density polyethylene (density of 0.96 g/cm3). ... various length and multiplicity will
develop. ... where the neutrons have not been moderated to thermal energies.

Download PDF - eScholarship

26 Sep 2012 ... nondestructively quantify the plutonium content of spent nuclear fuel ... degree of
realism in simulation space than has been done before, ..... applied to neutron
multiplicity measurements of uranium fuel rods [12]. ... that have been moderated
and reflected toward the assembly, i.e. thermal neutron albedo.

Joint U.S.-U.K. Report on Technical Cooperation for Arms Control

Joint Measurement Campaign . .... Table 2: Summary of Joint Measurement and
Data Analysis .......... ..... plutonium-based warhead) were as declared and that
they were be- ... nuclear device with actual fissile material and simulated high ...
gamma detection, autoradiography, neutron multiplicity .... 0.5” polyethylene
upper.

Alternative Method for Determining Plutonium-240 Content - Trace ...

algorithm was verified using NMIS simulated and measured data, and the ......
spontaneous fission in both the energy spectrum and the neutron multiplicity .....
steel container with a polyethylene moderator or neutron shield, designed for Pu
...

Development of a New Multiplying Assembly for Research ...

of the assembly, using either polyethylene or tungsten, are possible ... half-
century computer modeling and simulations have grown ... reflectors, changing
moderators, etc) produces a versatile ... plutonium.[9]). Most experimental
research campaigns dealing with neutron multiplicity and neutron multiplication
measurements.

A Very High Efficiency Neutron Counter for the Measurement of ...

Drum Monitor used for measuring plutonium in intermediate and low level waste (
LLW) .... polyethylene moderator assembly to slow down fast fission neutrons.

Polyethylene-reflected plutonium metal sphere : subcritical neutron ...

Neutron and photon emissions from the plutonium sphere were measured ..... 8.1
Neutron Multiplicity Counter Response versus Polyethylene Reflector
Temperature . ..... Figure 16: Schematic of the LANL NPOD-3 polyethylene
moderator block ...... The simulation of the plutonium sphere measurement used
two 12.7-cm ...

THE USE OF FAST NEUTRON DETECTION FOR MATERIALS ...

25 Feb 2014 ... moderating polyethylene or in the 3He where they are counted, and is ... ago
when plutonium accountability was first needed. ... being the multiplicity (number
of neutrons measured for a particular .... Pairs coincidence precision as a function
of neutron rate for (a) measured 252Cf sources and (b) simulated.

Monte Carlo Simulation of an Active Neutron Counter for Fissile ...

Monte Carlo Simulation of an Active Neutron Counter for Fissile Material
Accounting. Seong Kyu ... developed for the measurement of special nuclear
materials ... are based on spontaneous fission from plutonium or ... needs a
polyethylene moderator (refer to the 'source- ... Average fission multiplicity is 2.45
, which means.

Untitled - IITK - Indian Institute of Technology Kanpur

Computational Evaluation of Neutron Multiplicity. Measurements of Polyethylene-
Reflected Plutonium. Metal ... Multiobjective Simulated Annealing Employing.
Adaptively ..... moderate for comparatively lower flow rates.30 Any possible ...

Computation of Neutron Multiplicity Statistics Using Deterministic ...

16 Apr 2015 ... neutron multiplicity counting measurements without relying on the point ... Index
Terms—Coincidence techniques, neutron detectors, inverse problems,
simulation. ..... in a polyethylene moderator was used to accumulate the neutron
... The measured and calculated Feynman-Y for the plutonium source ...

Simulation of moderated plutonium neutron multiplicity measurements

Simulation of moderated plutonium neutron multiplicity measurements ... metal
plutonium sphere surrounded by up to 6 inches of polyethylene shells has ...

A Portable Neutron Counter for Field Surveys and Assay - the UNGM

A portable handheld neutron counter (PHNC) has been developed to ...
simulations. ... would facilitate large area surveys, identification of plutonium-
bearing ... Coincidence counting can provide verification measurement ...
junction box, high-density polyethylene moderator and reflector. .... Multiplicity
Counters,” Nucl.

Joint U.S.-U.K. Report on Technical Cooperation for Arms Control

Joint Measurement Campaign . .... Table 2: Summary of Joint Measurement and
Data Analysis .......... ..... plutonium-based warhead) were as declared and that
they were be- ... nuclear device with actual fissile material and simulated high ...
gamma detection, autoradiography, neutron multiplicity .... 0.5” polyethylene
upper.

Untitled - IITK - Indian Institute of Technology Kanpur

Computational Evaluation of Neutron Multiplicity. Measurements of Polyethylene-
Reflected Plutonium. Metal ... Multiobjective Simulated Annealing Employing.
Adaptively ..... moderate for comparatively lower flow rates.30 Any possible ...

Total Plutonium Content Determination with the Differential ... - INMM

Total Plutonium Content Determination in Pressurized-Water Reactor Spent Fuel
... means of high fidelity neutron transport simulations the ability of the DDSI ...
density polyethylene (density of 0.96 g/cm3). ... various length and multiplicity will
develop. ... where the neutrons have not been moderated to thermal energies.

Monte Carlo simulations of neutron coincidence counting systems in ...

is performed using neutron multiplicity decoders such as Canberra JSR12 or
AMSR. ... high-density polyethylene (HDPE), moderator and reflector material. ...
mode to measure the plutonium held in small dimension containers (typical HxØ
= ...

THE USE OF FAST NEUTRON DETECTION FOR MATERIALS ...

25 Feb 2014 ... moderating polyethylene or in the 3He where they are counted, and is ... ago
when plutonium accountability was first needed. ... being the multiplicity (number
of neutrons measured for a particular .... Pairs coincidence precision as a function
of neutron rate for (a) measured 252Cf sources and (b) simulated.

A Very High Efficiency Neutron Counter for the Measurement of ...

Drum Monitor used for measuring plutonium in intermediate and low level waste (
LLW) ... polyethylene moderator assembly to slow down fast fission neutrons.

MCNPX-PoliMi simulation capacity using thermal neutron cross ...

neutron multiplicity measurements are useful to determine plutonium mass which
may be used as a warhead ... Thermal neutron cross-sections for the moderating
material .... D. Sprevak and J.U. Koppel, Neutron Scattering by Polyethylene,.

Development of a New Multiplying Assembly for Research ...

of the assembly, using either polyethylene or tungsten, are possible ... half-
century computer modeling and simulations have grown ... reflectors, changing
moderators, etc) produces a versatile ... plutonium.[9]). Most experimental
research campaigns dealing with neutron multiplicity and neutron multiplication
measurements.

neutron coincidence counter: Topics by WorldWideScience.org

Evaluation of a fast neutron coincidence counter for the measurements of
uranium ... (HLNCC) implementation: assay of the plutonium content of mixed-
oxide fuel assemblies .... The traditional shift registers or multiplicity counters give
only multiplicity .... from fission by He-3 detectors embedded in a polyethylene
moderator.

Simulations of neutron multiplicity measurements o..|INIS - IAEA

Simulations of neutron multiplicity measurements of a weapons-grade plutonium
... plutonium that was moderated with various thicknesses of polyethylene.

Measurement Techniques for Warhead Authentication with ...

Passive and active neutron and gamma measurements assessing ..... Active
Neutron. Multiplicity. Counting. Not vulnerable to moderate external shielding .....
done with 200 g and 1 kg uranium sources shielded by 22 cm polyethylene,
which is .... MCNP simulations were performed for a 2 kg plutonium sample (solid
sphere ...

Multiplication and Presence of Shielding Material from Time ...

13 Jan 2017 ... Pulse-Height Measurements of Subcritical Plutonium Assemblies. Mateusz ...
tungsten, and 2.54 cm and 7.62 cm of polyethylene. A new ... tron capture based
multiplicity counters. ... Z moderators scattering neutrons slow down significantly
... highly enriched uranium [7] measurements and simulations. [8].

Methods for Attribute Measurement and Alternatives to Multiplicity ...

mass of the plutonium (to 10% of true mass 90% of the time) ... Neutron
multiplicity measurements utilize an array of moderated pressurized helium-3
detectors to determine ..... scintillator or helium-3 counter placed in the center of
polyethylene.

Securing special nuclear material: Recent advances in neutron ...

Neutron detection is an integral part of the global effort to prevent the .... All SNM,
including both highly enriched uranium (HEU) and plutonium (Pu), emits
neutrons. ..... Measuring this signature, commonly called multiplicity counting,
exploits the fact ..... neutrons incident on various thicknesses of a polyethylene
moderator.

MCNPX-PoliMi simulation capacity using thermal neutron cross ...

neutron multiplicity measurements are useful to determine plutonium mass which
may be used as a warhead ... Thermal neutron cross-sections for the moderating
material .... D. Sprevak and J.U. Koppel, Neutron Scattering by Polyethylene,.

design of a neutron spectrometer and simulations of neutron ... - K-REx

polyethylene moderator to identify sources based on energy spectrum. Sources
are iden- ... plutonium sphere with various reflector thicknesses were simulated.
.... 5 Simulations of Neutron Multiplicity Measurements with Perturbations to.

Simulation of polyethylene-moderated plutonium neutron multiplicity ...

Simulation of polyethylene-moderated plutonium neutron multiplicity
measurements Neutron multiplicity measurements are a useful technique for the
...

Computation of Neutron Multiplicity Statistics Using Deterministic ...

16 Apr 2015 ... neutron multiplicity counting measurements without relying on the point ... Index
Terms—Coincidence techniques, neutron detectors, inverse problems,
simulation. ..... in a polyethylene moderator was used to accumulate the neutron
... The measured and calculated Feynman-Y for the plutonium source ...

Computation of Neutron Multiplicity Statistics using Deterministic ...

Consequently, neutron multiplicity counting measures the distribution of neutron
... weapons-grade plutonium metal, reflected by a 76.2-mm-thick spherical shell
of polyethylene. ... attempt to accurately simulate the distribution of the neutrons
over position .... in a polyethylene moderator was used to accumulate the neutron
...

Technology R&D for Arms Control - International Panel on Fissile ...

Attribute Measurement System with Information Barrier Technology . ...
Measuring Plutonium Mass by Neutron Multiplicity Counting . ...... By using a
simulated Soviet SS-20, instru- mentation is developed ...... Polyethylene
moderator. Tungsten ...

Multiplication and Presence of Shielding Material from Time ...

13 Jan 2017 ... Pulse-Height Measurements of Subcritical Plutonium Assemblies. Mateusz ...
tungsten, and 2.54 cm and 7.62 cm of polyethylene. A new ... tron capture based
multiplicity counters. ... Z moderators scattering neutrons slow down significantly
... highly enriched uranium [7] measurements and simulations. [8].

ABSTRACT

detector responses in subcritical experiments and simulations. ... the sensitivity of
neutron multiplicity counting moments of arbitrarily high order. Each moment is ...
multiplicity counting measurements of a subcritical plutonium metal sphere. .....
Figure 3.13 Ratio of mean adjoint scalar fluxes: 1.5in polyethylene:bare, over the.

Sub-barrier photofission measurements in <sup>238</sup>U and ...

151B.2 Prompt Photossion Neutron Multiplicity Data . ...... polyethylene moderator
of the INVS in the geant4 simulation has the e ect of increasing the detector ...

Joint U.S.-U.K. Report on Technical Cooperation for Arms Control

Joint Measurement Campaign . .... Table 2: Summary of Joint Measurement and
Data Analysis .......... ..... plutonium-based warhead) were as declared and that
they were be- ... nuclear device with actual fissile material and simulated high ...
gamma detection, autoradiography, neutron multiplicity .... 0.5” polyethylene
upper.

Characterizing the detector response and testing the ... - Scintacor

COINCIDENCE MEASUREMENTS OF PLUTONIUM IN RESIDUES ... tubes arid
polyethylene-moderator typically have die-away times of 22-50 ps and
efficiencies of .... Neutron Multiplicity Counter (TNMC) [5] is a counter based on 4-
atmosphere 3He tubes and has a z ... A 252Cf source simulated the total neutron.

Measured and Theoretical Errors for Multiplicity Counting Neutron ...

3 Nov 2014 ... simulation using MCNP we found that MCNP had overestimated the results by ...
ity counting to determine the fissile mass of the plutonium or uranium being ...
Polyethylene is a well known neutron moderator and used in.

Joint U.S.-U.K. Report on Technical Cooperation for Arms Control

Joint Measurement Campaign . .... Table 2: Summary of Joint Measurement and
Data Analysis .......... ..... plutonium-based warhead) were as declared and that
they were be- ... nuclear device with actual fissile material and simulated high ...
gamma detection, autoradiography, neutron multiplicity .... 0.5” polyethylene
upper.

Measurement Techniques for Warhead Authentication with ...

Passive and active neutron and gamma measurements assessing ..... Active
Neutron. Multiplicity. Counting. Not vulnerable to moderate external shielding .....
done with 200 g and 1 kg uranium sources shielded by 22 cm polyethylene,
which is .... MCNP simulations were performed for a 2 kg plutonium sample (solid
sphere ...

Application of Active and Passive Neutron Non Destructive ... - CEA

The application of passive and active neutron measurements on low density
waste ... It can be deduced from calibration experiments and/or numerical
simulation. ... in the graphite and polyethylene walls of the assay system; -
thermal neutrons ... active neutron coincidence counting, and active neutron
multiplicity counting.

Präsentation

Case Study: Neutron Multiplicity Counting .... Plutonium Scrap Multiplicity
Counter (PSMC), ... Simulation and measurements should yield Pu mass! Geant4
PSMC. Detector Model. 5 SF in Detector cavity. Polyethylene Block. (Moderator).
He3- ...

He-4 Fast Neutron Detectors in Nuclear Security ... - ETH E-Collection

The first one is a novel method to measure the plutonium mass in a container ......
process does not absorb neutrons neither in the moderator nor in the capture
reaction, the ..... denote states with the same multiplicity as the ground state,
lower case letters a, b, c denote ...... This was confirmed by Arktis internal
simulations.

Neutron Coincidence Counting Studies - Pacific Northwest National ...

the project Coincidence Counting With Boron-Based Alternative Neutron
Detection Technology ... The efficiency comparison for measured and simulated
responses of a ... Pacific Northwest National Laboratory. Plutonium. Pressurized
water reactor ...... stack of 3He tubes that were removed from the polyethylene
moderator ...

The Graduate School The College of Engineering

accuracy. I present this method and benchmark it against both measured data
and a theoretical model. I also use the model to simulate a Feynman Beta curve
and ... 2.6.2 The Neutron Coincidence Counting Method of Multiplicity. Analysis .
..... dissertation is a ball of nuclear metal surrounded by a polyethylene well-
counter.

Plenary I - IRIS UniPA

A liquid scintillator fast neutron multiplicity counter - Steven Sheets (USA) .....
Monte Carlo simulations and benchmark measurements on the response of TE(
TE) .... Fast radiometric method for plutonium monitoring in environmental
matrices ...... neutrons from a 252Cf neutron source located in a polyethylene
moderator with.

Simulation of polyethylene-moderated plutonium neutron multiplicity ...

2 Feb 2011 ... Neutron multiplicity measurements are a useful technique for the characterization
of special nuclear material. This technique relies on the ...

THE USE OF FAST NEUTRON DETECTION FOR MATERIALS ...

25 Feb 2014 ... moderating polyethylene or in the 3He where they are counted, and is ... ago
when plutonium accountability was first needed. ... being the multiplicity (number
of neutrons measured for a particular .... Pairs coincidence precision as a function
of neutron rate for (a) measured 252Cf sources and (b) simulated.

Minutes of the Ninth Neutron Users' Club Meeting : Collaboration ...

24 May 2010 ... V E Lewis, D J Thomas, Section Heads, Neutron Measurement Group ... Thermal
neutron fields are produced by moderating fast neutrons produced by ... section
of the polyethylene used in its construction has been investigated. ..... that the
240Pu effective mass for plutonium bearing material is given by:.

panwas: a passive/active neutron waste assay system for the ...

2 Mar 2006 ... Nucleco required a waste assay system for the measurement of a wide ... thorium
and plutonium. ... located in cadmium shielded polyethylene moderator
assemblies in .... well as corrections (using the neutron multiplicity data) for the
effects ... size (200 liter and 400 liter) and inactive simulated waste matrix.

Measurement Techniques for Warhead Authentication with ...

Passive and active neutron and gamma measurements assessing ..... Active
Neutron. Multiplicity. Counting. Not vulnerable to moderate external shielding .....
done with 200 g and 1 kg uranium sources shielded by 22 cm polyethylene,
which is .... MCNP simulations were performed for a 2 kg plutonium sample (solid
sphere ...

Nuclear Measurements, Evaluations and Applications (NEMEA-7 ...

8 Nov 2013 ... and facilitate improved simulations of a wide range of nuclear integral
measurements. ...... One or more polyethylene samples of similar geometry are
...... Large fluctuations of the neutron multiplicity were measured in the resonance
range. ...... (2012), “CEA-2012: New Uranium and Plutonium Evaluations,.

A Very High Efficiency Neutron Counter for the Measurement of ...

Drum Monitor used for measuring plutonium in intermediate and low level waste (
LLW) ... polyethylene moderator assembly to slow down fast fission neutrons.

panwas: a passive/active neutron waste assay system for the ...

2 Mar 2006 ... Nucleco required a waste assay system for the measurement of a wide ... thorium
and plutonium. ... located in cadmium shielded polyethylene moderator
assemblies in .... well as corrections (using the neutron multiplicity data) for the
effects ... size (200 liter and 400 liter) and inactive simulated waste matrix.

ASTM Nuclear Portal » New Standards

C833-17 Standard Specification for Sintered (Uranium-Plutonium) Dioxide
Pellets ... for Nondestructive Assay of Plutonium by Passive Neutron Multiplicity
Counting ... Carbon Steel and Alloy Steel for Moderate and High Temperature
Service ... E523-16 Standard Test Method for Measuring Fast-Neutron Reaction
Rates by ...

Simulations of Neutron Multiplicity Measurements of a Weapons ...

Simulations of Neutron Multiplicity Measurements of a Weapons-Grade
Plutonium ... plutonium that was moderated with various thicknesses of
polyethylene.

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