reactor neutrino detection for non proliferation with the ... · amanda porta – cea saclay taup...

Amanda Porta – CEA Saclay TAUP 2009

Reactor Neutrino Detection for Non Proliferation with the NUCIFER Experiment

A. Porta for the NUCIFER collaboration

NUCIFER Collaboration: CEA-DSM, Saclay, France; CEA-DAM, Bruyères-le-Chatel, France; IN2P3-Subatech, CNRS/IN2P3, EMN, Université, Nantes, France;

APC, Paris, France

Index:● Reactor neutrinos

● Remote control of nuclear reactors ● The NUCIFER project

Amanda Porta – CEA Saclay TAUP 2009 2

Reactor neutrino emission and detection

e

Emission: -decay of fission products

● ~ 6 / fission ● ~1021 /s for a 1 GW

el reactor

e

-decaysfission

ν e + p → e+ + n

Prompt e+ signalEprompt = Eν -(Mn-Mp)+me

Delayed n captureafter thermalization ~ 30 s

Detection:

Threshold: Mn - Mp + Me = 1.8 MeV

1ton target @ 25m of 1GWel reactor gives ~4600 int./day ➞ 1% stat within 2 days

Miniature detector and high statistical precision

Detection reaction cross section ~10-43 cm2

→ typical detector masses: many 10 tons - some ktons

n rich stable


2.84 MeV2.94 MeV< Eν >

(Eν >1.8 MeV)

≈ 2.76 10-43 cm2

≈ 3.2 10-43 cm2

< σ ν int >

1.451.92ν / fission

(Eν >1.8 MeV)

198.9 MeV193.5 MeVE / fission *

239Pu235U

* E=Edep

-E

N νU

N νPu= fission×

U

fission× Pu

E fission Pu

E fission U~1.6

Pth = cst

Dependence of neutrino flux on fuel composition.


Non-proliferation: IAEA interest

IAEA specifications for neutrino detectors:● Safe and robust● Compact● Easy to be used● Remote controlled

In October, the IAEA Novel Technologies group has host a meeting in Vienna to chart a path towards a safeguards deployment based on neutrino detection.Outcomes → R&D recommendation and possibility of becoming officially part of AIEA development program

What neutrinos can say:● flux directly related to the fission process in the core, i.e. to the core composition● Real-time information on isotopic fission rates● flux cannot be controlled or shielded ● Non-intrusive, continuous and remotely operated method


SONGS1 measurement

Reactor Power (%)

-20

0

20

40

60

80

100

Date

06/2005 10/2005 02/2006 06/2006 10/2006

Detected Antineutrinos per day

0

100

200

300

400

500

Predicted rate

Reported power

Observed rate, 30 day average

Cycle 14Cycle 13outage

Cycle 13

Removal of 250 kg 239Pu, replacementwith 1.5 tons of fresh 235U fuel

LLNL/Sandia Antineutrino Detector,Bowden @ AAP 2007

LLNL/SANDIA detector results:

● 1.1 GWel ➞ ~1021 ν /s● Target: 0.64 t of Gd doped liq. scint. ● Detection efficiency ~11%

Det

ecte

d ne

utri

no c

andi

date

s per

day

Rea

cto

r P

ow

er

(%)

Nν=γ [1kt ]P th

Fuel composition (time dependent)

Detector (constant)

Neutrino rate:


The NUCIFER detector

● 16 PMTs of 8 inch

● 25 cm acrylic buffer

● Target: 0.85 m3 Gd doped liquid scintillator

1.2 m

1.8

m


Simulated detector response

Number of photoelectrons generated by e+ of 1 MeV with selected initial positions on z axis:

z scan

PM

Ts

Target center

PM

Ts

Target center

Detection efficiency of neutrons of 20 KeV generated in selected positions on z axis (energy threshold = 4MeV)

Energy resolution @ 4 MeV : 6 %

detection efficiency: ~ 50%


● 2009: detector construction● 2010: commissioning at OSIRIS research reactor (CEA-Saclay)● End 2011: calibration at ILL (Grenoble) research reactor (pure 235U spectrum)● Late 2012: NUCIFER at a Nuclear Power Station

NUCIFER road-map

OSIRIS: Pth=70 MW

the core

-11m P.Durande-Ayme @ TRTR-IGORR joint meeting 2005

7 m


with plastic scintillator

n with NE213

Nev

Background measurement at the research reactors

SB=

R

Racc

SB=

R

Rcor

Accidental background (+n capture): Correlated background (p recoil+n capture):

To be improved with PSD

at Osiris: attenuation respect to surface ~2.7

Ni

FeAl

Co K

Radiative capturesRadioactive elements with Ge

= 0.56 = 0.25


Background reductionShielding:● Active -veto● 14 cm of Polyethylene → n shielding● 10 cm Pb → shielding

PSD in organic liquid scintillators: due to long-lived decay of scintillator light caused by high dE/dx particles

Q tot

Q t

ail

n

Very preliminary


2 fixed fuel compositions (in fraction of fissions per isotope):End of the cycle: 235U=0.5 239Pu=0.5Beginning of the cycle: 235U=0.7 239Pu=0.3

~7 days of data taking (for NUCIFER @ 25 m from 1GW

el reactor)

Null Hypothesis of 2 statistical test: the two compositions induce identical phe spectra:

➢ Rate change: Hp rejected with 99.99 % C.L. ➢ Shape change: Hp rejected with 25% C.L.

Simulation of response to core evolution

Following the burn-up:

Reactor emitted spectrum from MURE + BESTIOLE simulation package


NUCIFER @ 25 m from 1GWel PWR:

with 2 relative measurements of 15 days of data before and after the reactor stop the retrieval of 80 kg of Pu can be seen with 75% C.L. and 4% probability of false alarm.

Sensitivity to Pu content

+

+

time

Det

ecte

d

rate

Reactor stop


Conclusions

Neutrino detection is a promising method for reactor survey: ● The challenge is a small detector close to the earth surface

● Accurate simulations of reactor neutrino spectra and detector response

➔ If we go at some 10 m from reactor core with a 1 ton detector we can have a good statistic within few days

➔ Accurate measurements to optimize the background shielding and background rejection method

First event expected for beginning 2010!!!!


Back-up slides


SONGS detector deployed at the San Onofre Nuclear Generating Station

• 3.4 GWth ➞ ~1021 ν /s• 3800 int. expected per day in 1m3 liq. scint. target • Dimensions: 2.5x3 m2, 0.64t of Gd doped liquid scintillator,

8 PMTs, water shielding, plastic muon veto• Detection efficiency: 11%• Low cost and robust detector• Automated, non intrusive measurement

Back up slide: the LLNL/Sandia detector

NIM A 572 (2007) 985, J. Appl. Phys. 103, 074905 (2008)


Back up slide: Power measurement

35% constant E resolution

Pth = cst !

Normalized to T=1day

1+k(t) parameter: simulation of 1 year cycle of a PWR reactor @ Pe = 0.9 GW: 10% decrease

Yu.V.Klimov et. al., Atomic Energy, vol. 76, n. 2 (1994)

Reactor power in % of 1375 MW

Rat

e p

er 1

05 sec

nν /(1+k) = γ Wth

γ =0.733 ± 0.005 evt./MWth

Proportionality to Pth after burn-up correction

Rovno experiment results:

Integral flux measurement over 1 cycle is a cross check of fuel composition and thermal power declared in the books by the Power Station

Nν=γ [1kt ]P th

Fuel composition (time dependent)

Detector (constant)

Neutrino rate:


Back up slide: the Rovno experiment (1986)

PWR Rovno reactor (Russia)1.3 GWth

~1m3 of mineral oil + 0.5 g/l Gdd= 0.78 g/cm3 84 PMT, ε det – ~50%

Shielded by: 15 cm of steel, 50 cm of bored polyethylene liquid scintillator active shielding on the top


Back up slide: neutrino energy spectrum from 235U and 239Pu


OngoingHP-GeTawainTexono

On site R&DLSAngra, BrazilANGRA

In preparationLS @ 120 mweRovno, RussiaROVNO new

In preparationLS @ 120 mweChooz, FranceDouble Chooz

Funded1.2t LSFranceNUCIFER

Ongoing1t LS @ surfaceJoyo - JapanKASKA

OngoingHP-GeSan Onofre, USSONGS

OngoingGd-H20San Onofre, USSONGS

OngoingPS @ 20 mweSan Onofre, USSONGS

Done - Pth & Burnup0.5t LS @ 20mweSan Onofre, USSONGS

Done - Pth & Burnup1t LSRovno, RussiaROVNO old

StatusSetupSiteExperiment

Back up slide: worldwide effort


Back up slide:Liquid scintillator: Eljen Technology EJ335-0.1/0.5%

COMPONENT % WT.1,2,4Tlimethylbenzene < 40%USPWhite Oil >60%Organic f1uors <0.2%

Physical propertiesBOILING POINT > 200°C (390°F)MELTING POINT Not applicableSPECIFIC GRAVITY (H20=1) 0.87 at 20°C.VAPOR PRESSURE (mm Hg) < 1 mm @ 20°C (68°F)VAPOR DENSITY (air =1) approx.4PERCENT VOLATILE BY VOLUME (%) <40%EVAPORATION RATE (butyl acetate=1) very slowSOLUBILITY IN WATER Nil


Back up slide: testing the PSD of NUCIFER scintillatorFacility set-up

Method:

neutrons

gammas

Results:


Back up slide: Reactor neutrino simulation

deployed by Double Chooz Collaboration

Inputs: • n flux • initial composition • core geometry

Monte-Carlo Simulation:Evolution Code MURE

Inputs: nuclear database exp. spectrum models

-branch database: BESTIOLE

Relative rate of fissions of each isotope at time t.

ν spectrum for β decays of each isotope

Nν (Eν ,t) = Σ i ( t) . Si (Eν )

Advantage: full error propagation under control


● Good agreement with reference spectrum● Improvement of construction method from to spectrum

The energy spectrum of neutrinos from pure 235U fission is well simulated from cumulative fission yields:

Th. Mueller, PhD Thesis

Full error and bin correlation treatment

Back up slide: Simulation results


Simulation of detection of neutrinos for different core compositions:0.70 235U + 0.30 239Pu0.65 235U + 0.35 239Pu..................................0.50 235U + 0.50 239Pu

N 1±N 1

N 2±N 2

2=N 1−N 2

2

N 1N 2

● The red curve in case of an unchanged reactor (no change in rate)● The green curve in the case of change of 10% in core composition → extraction of 105 kg of Pu

NUCIFER at 25 m from 1GWel PWR:

with 2 relative measurements of 15 days of data before and after the reactor stop the retrieval of 80 kg of Pu can be seen with 75% C.L. and 4% probability of false alarm

Back up slide: Sensitivity to Pu content

reactor neutrino detection for non proliferation with the ... · amanda porta – cea saclay taup...

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