mechanical design of astor bunker peirone vdenim2020

Mario A Peirone

Virtual DENIM 2020Mechanical Design of ASTOR Bunker

LABORATORIO ARGENTINODE HACES DE NEUTRONESLAHN

September 14-17, 2020 1San Carlos de Bariloche, Argentina

Contents1. Introduction to LAHN and ASTOR 2. Scope and Bunker´s function3. Design process first iteration4. Description of concepts:

a. Homogeneous material: Heavy Concrete b. Steel and Boron Polyethylene

5. Comparision of the two conceptsa. Estimated Materials and Costb. General Evaluation


ASTOR: Advanced System for TOmography and Radiography

It is the neutron imaging instrument under developmentfor the LAHN project.

1. Introduction to ASTOR


Its main function is to guarantee a dose of less than 3µSv/h in the reactor hall2. The Bunker’s function

Flux (n/cm2.s)for Min. collimation position• Cold 3.7 e8• Thermal 1.4 e8• Epithermal 4.3 e7• Fast 5.2 e6

SCOPEIntroduce, in the context of ASTOR's mechanical design, the approach being taken to make a comprehensive evaluation of possible shielding materials to be used for the ASTOR Bunker


1st Concept generation• Steel blocks filled with

shielding material• Wall thickness considered:

750mm• Roof thickness considered:

550mm

Radiologial shieldingdesign of ASTOR. Feedback: Estimationof required thicknessesfor different shieldingmaterials

Work in progress: exploring 2 differentsolutions. • Multilayered walls• Steel blocks filled with

homogeneous shieldingmaterials

3.Design process first iteration

• Two Rooms• Collimator and Secondary Shutter embedded• Beam stop embedded• Blocks: Metallic blocks filled with shielding material• Lateral opening doors

INTERNAL DIMENSIONS

• 3.6m wide• 17m long• Beam Conformation

room 2.5m high• Experimental room

3.7m high





550mm








550mm





• 20ton Polar Crane capacity• Polar crane reach• Building roof is 5.9m high• 20ton/m2 maximum load on

the floor• A Bunker that can be

assembled and disassembled at any time

• Length of Bunker

Some design constraints:


A) Description of the Heavy Concrete concept:

B) Description of Steel and Polyethylene concept

Aspects used for concepts evaluation :

• The least number of type of blocks• Estimated Cost. The bunker cost should not be greater than 55% of the

budget of the instrument.• Wall thickness required• Ease of construction• Ease of assembly • Achieved tolerances in the blocks dimensions


• The interior dimensions • 20tons/m2 maximum load

on the floor• A Bunker that can be


• Avoid any free path for neutrons and radiation in the gaps between blocks

• The shielding material is heavy concrete 3400kg/m3

• The thickness is 980mm

Design requirements:

4.a Description of the Heavy Concrete concept


• Divide the Bunker into an internal and an external part.

• The internal part is 573mm thick and the external part is 413mm thick

• Most of the blocks are rectangular.

Strategy:



• A frame of UPN profiles

Strategy:



• The block is finished with L profile beams and steel sheets.

• It is built in halves that are joined and then the concrete is poured.• 4 threaded bars are welded in the top, these are the lifting points.

Strategy:



• Most of the panels are rectangular but some of

the panels on the roof are not rectangular and some of the panels on the wall are angled

Strategy:



• Wall thickness achieved: 400+560+4x6.35=985,5mmStrategy:



• Panels can be joined by using a beam, also built with UPN profiles and

filled with heavy concrete.

Strategy:



• Assembly of the inner part of the Bunker

Strategy:



Strategy:• Assembly of the inner part of the Bunker



• Design criteria: Avoid free path

Strategy:



• The interior dimensions • 20tons/m2 maximum load

on the floor• A Bunker that can be


• Avoid any free path for neutrons and radiation in the gaps between blocks

• The shielding material is a mixture of 80% of steel and 20% of borated polyethylene

• The thickness is 580mm

Design criteria:

4.b Description of the Steel and Boron-Polyethylemeconcept


• Divide the Bunker into an internal and an external part with the same thickness.

• Most of the blocks are rectangular.

Strategy:



• The panels sandwiches are made of ¼’’ rectangular steel plates and

25mm thick boron-polyethylene plates.• 3 groups of 12 steel plates and 2 layers of polyethylene in one panel.

5. Description of the Steel and Boron-Polyethylemeconcept

Strategy:


• 2 sandwiches in the wall, the thickness achieved is

582mm with a 78.5% of steel


Strategy:


• Most of the panels are rectangular but some of the roof panels are not

rectangular and some of the wall panels have sheets of different dimensions.


Strategy:


• Assembly: The Bunker is divided

into 5 parts


Strategy:


• Assembly: The Bunker is

divided into 5 parts

Strategy:



• Design constrain: Avoid free path

Strategy:



• 355 UPN200 beams x6m

• 90 UPN160 beams x6m

• 200 L profile beams x6m

• 100 steel sheets 1.5m x3m x6.35mm

• 45m of round bars of 60mm and 80mm

• 320 screws DIN912 M30 x175mm

• 320 washers M30

• 180m3 of heavy concrete

• 3600 steel sheets 1.5m x3m x6.35mm

• 1100 boron-polyethylene plates

• 1000 threaded bars M30 x300mm

• 2000 nuts and washers M30

NOTE: An internal steel structure is needed to

support the roof, which is not included here.

Heavy concrete Steel and Ployethylene

5.Comparision of the two concepts-

Estimated Materials and Costs

• 180 m3 of heavy concrete @ 250 US$/m3

US$ 46,000

• 70 tons of steel @ 3 US$/kg

US$ 210,000

• Total estimated cost

US$ 256,000

• 800 tons of steel @ 3 US$/kg

US$ 2,400,000

• 25 tons of boron-polyethylene @ 20 US$/kg

US$ 500,000

• Total cost of material

US$ 2,900,000


Steel blocks filled withshielding material

Multilayered: Steel andBorated Polyethylen

Least number of types ofblocks

Wall Thickness required

Estimated cost. (Limit1.925MU$S)

Ease of construction

Ease of assembly

Achieved tolerances

Better WorseSimilar


• Both concepts are feasible in terms of manufacture

• Heavy Concrete concept seems to be much less expensive. • Although Steel and borated polyethylene would exceed the budget allocated

for the bunker, some hybrid solutions may still be considered. a) Using steel and borated polyethylene only in some placesb) Considering different thicknesses in some places

Conclusion


On behalf of the LAHN team

Thanks for your attention...


Questions ???


mechanical design of astor bunker peirone vdenim2020

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