Pure Polyethylene Neutron Shielding | JCS Nuclear Solutions

JCPEP is a pure, high molecular weight, polyethylene neutron shielding, frequently used as a moderator where it is desired to slow fast neutrons down to thermal energies for experimentation.

In these applications, it is highly desirable to maximise the hydrogen content and minimise any impurities, especially those that might absorb neutrons. We can supply high purity virgin polyethylene for this application in a variety of shapes and sizes.

JCPEP can be readily machined into complex shapes for applications involving neutron instrumentation, reactor physics, activation analysis or isotopic neutron sources. John Caunt Scientific can not only provide custom machining but can also pour JCPEP into custom-made moulds to provide application-specific shielding form.

Features at a glance

Used to thermalise fast neutrons
An excellent neutron moderator with very high hydrogen content
Available as slabs, bricks, pellets, rods and spheres
Other dimensions/shapes on request
Can be supplied machined to close tolerances

Uses

Linac Bunkers
Moderation
Medical Applications

The JCS borated neutron shielding assembly

Specifications

	Method	Units	Values
Properties
Colour	-	-	White, Black, colours
Density	ISO 1183-1	g/cm³	0.96
Thermal Properties
Melting temperature (DSC, 10°C (50°F) / min)	ISO 11357-1/-3	°C	135
Glass transition temperature (DSC, 20°C (68°F) / min)	ISO 11357-1/-2	°C	-
Thermal conductivity at 23°C (73°F)	-	W/(K.m)	0.4
Coefficient of linear thermal expansion (-40 to 150 °C) (-40 to 300°F)	ASTM E-831 (TMA)	µin./in./°F
Coefficient of linear thermal expansion (23 to 100°C) (73°F to 210°F)	-	µm/(m.K)	150
Heat Deflection Temperature: method A: 1.8 MPa (264 PSI)	ISO 75-1/-2	°C	44
Continuous allowable service temperature in air (20.000 hrs)	-	°C	80
Min. service temperature	-	°C	-100
Flammability: UL 94 (3 mm (1/8 in.))	-	-	HB
Flammability: Oxygen Index	ISO 4589-1/-2	%	<20
Mechanical Properties
Tensile strength	ISO 527-1/-2	MPa	28
Tensile strain (elongation) at yield	ISO 527-1/-2	%	10
Tensile strain (elongation) at break	ISO 527-1/-2	%	> 50
Tensile modulus of elasticity	ISO 527-1/-2	MPa	1300
Shear Strength	ASTM D732	MPa
Compressive stress at 1 / 2 / 5 % nominal strain	ISO 604	MPa	12 / 18.5 / 26.5
Compressive strength	ASTM D695	PSI	-
Charpy impact strength - unnotched	ISO 179-1/1eU	kJ/m²	no break
Charpy impact strength - notched	ISO 179-1/1eA	kJ/m²	105P
Charpy impact strength - double 14° notched	ISO 11542-2	kJ/m²	25
Izod Impact notched	ASTM D256	ft.lb./in
Flexural strength	ISO 178	MPa	27
Flexural modulus of elasticity	ISO 178	MPa	-
Relative volume loss during wear test "sand-slurry" : TIVAR® 1000=100	ISO 15527	-	350
Shore hardness D	ISO 868	-	62
Electric strength	IEC 60243-1	kV/mm	45
Electrical Properties
Volume resistivity	IEC 62631-3-1	Ohm.cm	10E13
Surface resistivity	ANSI/ESD STM 11.11	Ohm/sq.	10E12
Dielectric constant at 1 MHz	IEC 62631-2-1	-	-
Dissipation factor at 1 MHz	IEC 62631-2-1	-	-
Miscellaneous
Specific Gravity	ASTM D792	-	-
Water absorption after 24h immersion in water of 23°C (73°F)	ISO 62	%	< 0.1
Water absorption at saturation in water of 23 °C (73°F)	-	%	< 0.1
Wear rate	ISO 7148-2	µm/km	300
Dynamic Coefficient of Friction (-)	ISO 7148-2	-	0.15-0.30
Limiting PV at 100 FPM	QTM 55007	ft.lbs/in².min	-
Limiting PV at 0.1 / 1 m/s cylindrical sleeve bearings	-	Mpa.m/s	0.08 / 0.05
Note: 1 g/cm³ = 1,000 kg/m³ ; 1 MPa = 1 N/mm² ; 1 kV/mm = 1 MV/m

Features at a glance

Uses

Specifications

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