Quality control of neutron-absorber materials for the nuclear fuel cycle, Principle of the JEN-3 neutron Backscattering gauge

Transcription

1 Quality control of neutron-absorber materials for the nuclear fuel cycle, Principle of the JEN-3 neutron Backscattering gauge Hamid MAKIL (CEADRT/LIST/LCAE) Patrick BRISSET (IAEA) ICARST 2017, April 2017, Vienna, Austria

2 Quality control of neutron-absorber materials SOMMARY : OVERVIEW OF CEA/LCAE Laboratory GENERALITY NEUTRON SOURCES INTRODUCTION Radioisotopic sealed sources Accelerators Neutron beams delivred by reactors SOME INDUSTRIAL APPLICATIONS OF NEUTRON SOURCES Moisture content gauges Gauges designed for Gas remaining in gas bottle Nondestructive detection of explosives and drug contraband QUALITY CONTROL OF NEUTRON-ABSORBER MARERIELS FOR THE NUCLEAR FUEL CYCLE

3 OVERVIEW OF LCAE LABORATORY (LABORATORY OF SENSORS AND ELECTRONIC ARCHITECTURES) It conducts research and development around the nuclear instrumentation. It works on innovative technologies and projects such as the security of critical infrastructure and future nuclear reactors Radiation detectors capable to work and to have a sufficient lifetime under extreme conditions Three key topics : Defense, Security and Industry It contributes to the development of the sensors and associated electronics

4 GENERALITY NEUTRON SOURCES INTRODUCTION RADIOISOTOPIC SEALED SOURCES These are mainly: 252 Cf, spontaneous fission sources, which emits neutrons with an average energy of 2.5 MeV, 241 Am-Be (α,n) source with a higher average energy (about 4.5 MeV). 252 Cf is preferred when emphasis is on the neutron fluence : for the same activity and for a smaller size (due to its higher specific activity) the Californium source will emit 2000 times more of neutrons than the Americium-Beryllium one. However, the period of the 252 Cf (2.64 years) is unfavorable compared to 241 Am-Be (433 years).

5 GENERALITY NEUTRON SOURCES INTRODUCTION ACCELERATORS In this category, neutrons are generally produced by following main reactions: The large positive Q-values and the low atomic numbers make it possible to produce high yields of fast neutrons even at low-incident energies. Moreover, the use of pulsed neutrons allows to increase the areas of applications since the neutrons flux can reach n.s -1.st -1.

6 GENERALITY NEUTRON SOURCES INTRODUCTION NEUTRON BEAMS DELIVRED BY A RESEARCH REACTORS Generally used to obtain thermal neutrons for solid physics research or radiography purposes, the main advantage of this type of beam consists of very high flux of usable neutrons. For such applications ORPHEE, the CENTER OF RESEARCH OF SACLAY REACTOR, delivers a thermal flux of about 10 9 η.cm -2.s -1 on surface of 25x150 mm 2 with nearly no gamma background.

7 GENERALITY SOME INDUSTRIAL APPLICATIONS OF NEUTRON SOURCES MOISTURE CONTENT GAUGES The CEA has developed a device specifically designed to measure the humidity of sands used in the industrial production of concrete. Advantages of neutron systems for moisture measurements are simplicity, ruggedness and the ability to average over a large volume of material. Accuracy : 1% 1. Counter tube helium 3 2. Source 241 Am-Be (average activity of 10 GBq) 3. Tube sleeve 4. Fitting connection 5. Biological shielding 6. Transport container 7. Electronic 8. Remote control of gauge

8 GENERALITY SOME INDUSTRIAL APPLICATIONS OF NEUTRON SOURCES Gauges designed for Gas remaining in gas bottle A gauge designed to determine the quantity of gas remaining in a gas bottle just before refilling has also been developed by our laboratory. Two sources of 241 Am-Be are used with a total activity of 20 GBq. The interaction of neutrons with hydrogen (from butane or propane) gives a proportional signal of the quantity of gas. So, it allows an industrial on line control. Accuracy : 10g for 100g remaining

9 GENERALITY SOME INDUSTRIAL APPLICATIONS OF NEUTRON SOURCES NONDESTRUCTIVE DETECTION OF EXPLOSIVES AND DRUG CONTRABAND Explosives contain a high level of O and N and a low level of C and H, whereas narcotic materials contain a high level of C, H, Cl and a low level of O and N. So, by determining these elements, with high accuracy, in addition with the ratios C/O and (O+N)/C one can detect such hidden materials. The applied method, commonly named Pulsed Fast Neutron Analysis (PFNA), is a non-intrusive technique based on neutron time-of-flight measurements. So, it requires neutron generator tubes or accelerators. There is a large program on this subject and many papers have been published.

10 INDUSTRIAL APPLICATION Quality control of neutron-absorber materials QUALITY CONTROL OF NEUTRON-ABSORBER MATERIALS FOR THE NUCLEAR FUEL CYCLE These materials play a leading role in the nuclear fuel reprocessing industry to obviate the risk of criticality in the storage, the transport and the reprocessing of irradiated nuclear fuels. 2 MAIN FUNCTIONS : - Biological shielding - Separation to prevent the critical mass

11 INDUSTRIAL APPLICATION Quality control of neutron-absorber materials The CEA has designed several gauges to provide proof through non-destructive inspection that the finished products fully satisfy their intended objectives. The main geometries have been considered: Backscattering geometry Transmission geometry

12 INDUSTRIAL APPLICATION Quality control of neutron-absorber materials The CEA has developed various neutron gauges for inspection and control of neutron-absorber materials

13 INDUSTRIAL APPLICATIONS PRINCIPLE OF THE JEN-3 NEUTRON BACKSCATTERING GAUGE NEUTRONIC INSPECTION METHOD ON BORATED STEEL PLATES USING JEN3 JEN3 gauge is calibrated for a given thickness of steel plate by plotting the neutronic measurement versus boron content using plates with known boron content. Sensitivity : ±0,5 mg/cm 2 for a boron content of 10 mg/cm2 (t=40s) ±0,5 mg/cm2 for a boron content of 100 mg/cm2 (t=100s)

14 INDUSTRIAL APPLICATIONS PRINCIPLE OF THE JEN-3 NEUTRON BACKSCATTERING GAUGE PROCEDURE TO VERIFY UNIFORMITY OF THE BORON DISTRIBUTION IN THE SURFACE OF PLATE Rectangular meshing 200X200 mm 100% of surface 4400 mm mm

15 INDUSTRIAL APPLICATIONS PRINCIPLE OF THE JEN-3 NEUTRON BACKSCATTERING GAUGE ACCEPTABILITY CRITERIA The neutron measurement is affected by a randomness of the emission of the neutrons and their interactions with the matter so, the uniform distribution of the boron will be checked by an acceptability criteria : Every points N(i,j) shall be included in the following range : = N average ± a. N average = N(i,j) m.n = N average a = calibration parameter = 3 (under ideal conditions )

16 INDUSTRIAL APPLICATIONS PRINCIPLE OF THE JEN-3 NEUTRON BACKSCATTERING GAUGE NEUTRON SOURCE TYPE 252 Cf A = Bq (0, η/s/4π 0, η/s/4π ) T 1/2 (half-life) = 2,64 years The radioactivity decreases by about 2% per month 241 AmBe A = 5, , Bq (0, η/s/4π 0, η/s/4π ) T1/2 (half-life) = 433 years For the same neutron flux, the source of 252 Cf has a lower activity than the 241 AmBe. User must comply with national regulations concerning the possession and use of radioisotopes

17 INDUSTRIAL APPLICATIONS PRINCIPLE OF THE JEN-3 NEUTRON BACKSCATTERING GAUGE SAFETY AND RADIATION PROTECTION The source contains ( Bq) of the 252 Cf radioactive material It s certified material under special form It s double-sealed with two stailess steel capsules. Metric dimensions : diameter < 8 mm, length < 15 mm Activity (MBq) Dose equivalent µsv/h In contact Dose equivalent µsv/h 60 cm Dose equivalent µsv/h 100 cm Dose equivalent µsv/h 200 cm Dose equivalent µsv/h 300 cm ,5 4 2 < 0, < 0,5

18 INDUSTRIAL APPLICATIONS PRINCIPLE OF THE JEN-3 NEUTRON BACKSCATTERING GAUGE The first manual device JEN3 installed at BÖHLER (AUSTRIA. It is still the main tool for inspection and testing for borated steel plates. The JEN3 automatic device in the assembly and test phase. It was developed and installed since 2013 for the industrial CARPENTER in the USA,

19 INDUSTRIAL APPLICATIONS PRINCIPLE OF THE JEN-3 NEUTRON BACKSCATTERING GAUGE Automatic device JEN3 has become the essential inspection tool and a commercial reference for the industrial CARPENTER

20 Thank you for your attention Commissariat à l énergie atomique et aux énergies alternativ es Institut Carnot CEA LIST Centre de Saclay Gif-sur-Yv ette Cedex T. +33 (0) F. +33 (0) Direction Département Laboratoire : DRT : DM2I : LCAE Etablissement public à caractère industriel et commercial RCS Paris B