# Presentation: 745522

## FIRE Engineering Summary 

- Phil Heitzenroeder
- for the
- FIRE Engineering Team
- Presented to  the FIRE Physics Validation Review Committee  March 30, 2004

## Outline

- FIRE and its Status
- Engineering Evaluations of Coil Systems*
- R&D Plans for the Coil Systems*
- Costs
- Summary

****This talk concentrates on the coil systems  since the other key engineering systems *
*are covered in presentations by B. Nelson and M. Ulrickson.*

## Status

- The FIRE study began in late 1999.
- All major systems addressed.
- Preliminary cost estimates indicate a “green field” cost of $1.19B.
- Engineering Peer Reviews were held in  June‘01.  Included:
- TF and PF coils
- Vacuum Vessel and PFCs
- Fueling and Pumping
- Nuclear effects and Activation
- Cryoplant
- Facilities and Siting
- Focused set of parameters were adopted; R&D plans have been outlined.
- Participated in and received good feedback from SNOWMASS.
- Many of these inputs are now reflected in the design and the FIRE 2003-4 Engineering Report Update
- Work so far indicates  all major systems can be designed to meet or exceed requirements.

## FIRE Engineering Review Critical Issues (June 2001)

_**CRITICAL DESIGN ISSUES:**_
- 1. *FOCUS *in an expeditious manner on 2 Designs along the Q = 10 “zone,” (not the “Baseline” design) that indicate, at the Pre-Conceptual Design level, an Engineering Margin value in the range of 1.2 to 1.3. **(Done)**This level of margin should also apply to the insulation schemes. **(Agreed)**
- 2. Then *FOCUS*, in an expeditious manner on *one *device, either Wedged or Bucked/Wedged (to be selected by the design team.) **Done, Wedged 10T chosen**
- 3. Incorporated in the focusing effort should also be the *immediate *design attention to the details of leads, both TF and CS, associated cooling fittings and design of all other critical systems that are lacking detail at the Pre-Conceptual level - **(Not done, limited resources used to address more global issues - I.e.,rep rate)-** See the material below and the associated attached chits. **(about 1/3 of the chits have been addressed await resources for more detailed items.)**
_**CRITICAL R&D ISSUES:**_
- 1. The qualification of the properties, through R&D of the TF coil Materials (OFHC for the Bucked/Wedged and BeCu for the Wedged device) in sizes and thickness that are representative of those required for fabrication. **(Agreed, also Elbrudor for PF, will pursue if CD-0)**
- 2. For either device, the qualification, through R&D, of materials, that are available today, for the insulation systems. **(Agreed, 4 Small Business Innovative Research grants awarded by DOE for insulation development in support of FIRE/fusion needs.)**

## Key Components of FIRE

**Modular Tungsten Brush Divertors**

**Double ****Walled**** VV with Integral Shielding.**

**LN****2**** Cooled wedged Cu TF Coils**

**LN****2 ****Cooled Segmented Central Solenoid**

**Key Components of FIRE**

**LN2 Cooled Copper**
** ****PF Coils**

## Engineering Status of the TF Coil

- Stress and fatigue evaluations are performed in accordance with the  FIRE Structural Design Criteria.
**Structural stress allowable exceeds requirements:**
- Calculated max. membrane + bending stress:  611 MPa.
- M+B allowable for C17510 BeCu:  724 MPa.
**Shear allowable exceeds requirements:**
- Shear required :  50 MPa.
- Shear Developed: 60 MPa. (200 MPa compression; =0.3)
**Fatigue life exceeds requirements:**
- requirement: 3,000 full power shots (H-Mode) + 30,000 half power shots (L-Mode).
- Evaluation indicates 5,000 full power shots;  half  power shots far exceed requirements.
**Pulse Duration meets requirements:  **>20s flat-top  capability @10T

_**Structural model showing out of plane displacements **_

## Engineering Status of the Central Solenoid and PF Coils

**Structural stress allowable exceeds requirements:**
- 1.5 Sm Allowable for Elbrodur  at that temperature =541;
- Highest Max. VonMises stress is 414 MPa. at EOB for CS2 coils.
- Max. Temperature (at EOC) of  188 K.  Is well within temp. limit of 373 K.
- Fatigue: *more work required.*
- The  FIRE design criteria requires a  Factor of Safety  (FS) of 20 on the number of cycles
- The  CS-2 coil does not meet this requirement for H-mode operation;  its FS is 15.

## Meeting FIRE’s Operating Pulse Requirements 

- As noted in the previous slide, the CS-2 coil  falls short of the 20 X life “ASME-Like” fatigue, based on currently available fatigue information on Elbrodur .
- Possible remedies:
- Work with the copper suppliers to develop Elbrodur with improved fatigue properties and more extensive testing of existing materials.
- Use a strip-wound copper design for all CS and PF coils.
-  It is expected that metallurgical flaws will be smaller.
- inspection for flaws will be easier with strip compared to plate.
- Use a fracture based fatigue analysis rather than traditional fatigue analysis.
- This requires quantification of flaw size, but requirements for multiples of life are reduced to 4.
- Requires investigation to see if, with expected flaw size, this is a net win.
- Other possibilities:
- Carefully review the required operating pulse spectrum required for FIREs mission.  We may find that the current fatigue life  is acceptable.
- Another option might be to use the “aircraft approach” – i.e., design the engine (central solenoid)  to be readily replaced while still within its safe operating lifetime.

## Coil R&D Highlights

**FIRE’s magnet systems  have relatively modest R&D needs**:
- Cryo cooled copper design.
- Much data to draw upon from CIT/BPX; IGNITOR; ALCATOR C-Mod.
**R&D Focus:**
***Filling gaps*** in data bases of materials (Elbrodur; insulators)
- R&D which may permit ***higher performance*** (refined design criteria; optimized materials; improved inspection techniques)
***Cost reduction*** (manufacturing process development; materials selection)
***Risk mitigation*** (component testing; prototypes).

## TF Copper:  BeCu Plate Developed for BPX Should Meet FIRE’s Needs.   

- The C17510 BeCu plate shown was produced for BPX by Brush-Wellman.
***Properties and  size  are  very similar to those required for FIRE.***
- Brush-Wellman requires  modest R&D to establish production details.

## Copper Joining R&D 

-         C17510 BeCu
-         C10200 OFHC
- R&D is planned to develop friction stir or e-beam welding for joining the TF copper segments.
- R&D is also planned for electroform welding for possible use in the PF coils.

## PF Coil Conductor R&D  

- The CS and ring coils all use “Elbrodur” CuCrZr copper.
- R&D will focus on:
- Processing to optimize fatigue properties.
- Inspection techniques to reliably measure flaw sizes.
- Characterization of physical properties for the Elbrodur conductor in the sizes and forms  FIRE plans to use.

## Radiation Resistant Insulating Materials R&D    

- Requirements:
- FIRE plans 3,000 full power D-T shots producing  5 TJ of neutrons  + 30,000 half power D-D shots producing  0.5 TJ of neutrons.
-  End of life peak insulation dose:  1.05 x 1010 rads.
**BPX insulation would meet this requirement**
- This is a high leverage area since it has the potential of permitting a greater number of D-T shots .  It  has a strong bearing on reliability and risk mitigation.
- Plans:
- Collaborate with several existing SBIR’s which are underway to develop high radiation resistant insulating materials with good processing characteristics.
- Characterize and life test the friction characteristics of insulating materials required  between the CS coils and in the TF coils.

## Costs 

**Costs **

## Summary

- The FIRE study has addressed all  major systems.
- Results have been encouraging – no “show stoppers” in technical or cost areas.
- An Engineering Peer Review was held in 2001.
- FIRE adopted a focused set of parameters in FY 01, as recommended.
- The other detailed recommendations have been addressed.
- Favorable comments about depth of analysis, considering we are in Pre-Conceptual design phase.
- R&D plans have been developed.
- FIRE’s Cryo cooled Cu design has modest R&D requirements;  lots of data to draw upon.
- R&D will focus on areas which will reduce uncertainties and costs and can improve performance.
- FIRE participated in and received much feedback from SNOWMASS in ’02.  Much of this has been factored into FIRE’s design and plans.
- Preliminary cost estimate is $1.19 B.  If a site with modest credits is  identified, the $1B cost goal can most likely be achieved.