# Presentation: 630103

## Status of 3-D Analysis, Neutron Streaming through Penetrations, and LOCA/LOFA Analysis

-  L. El-Guebaly,
- M. Sawan, P. Wilson, D. Henderson, A. Ibrahim,
-  G. Sviatoslavsky, B. Kiedrowski, T. Tautges, C. Martin
- Fusion Technology Institute
- UW - Madison
**Contributors:**
- X. Wang, S. Malang (UCSD)
**ARIES-CS Project Meeting**
- October 4 - 5,  2006
- PPPL

## Final Radial Build(http://fti.neep.wisc.edu/aries-cs/builds/build.html)(5.3 MW/m2 Peak NWL)

## Status of 3-D TBR Analysis

**Purpose**: compute overall TBR and Mn
- CAD model received from UCSD on 9/19/06 including:
- FW/Blanket/BW
- Shield
- Manifolds
- VV
- Magnet
- Divertor
- No penetrations!
- Essential components for TBR and Mn will be included in 3-D model:
- FW/Blanket/BW
- Shield
- Manifolds (continuous)
- Divertor
- ECH ducts (to be added by UW).

## Status of 3-D TBR Analysis (Cont.)

- Complex 3-D problem, requiring many time-consuming iterations.
- UW had difficult time transferring UCSD model into ACIS.
- UW manipulated UCSD geometry to merge properly even though Xueren tried improving accuracy settings in Pro/E.
- Clean model shows no sign of overlapping. **3-D analysis in progress**.
- Future ARIES modeling work should be produced in ACIS*.

- ___________
- * Commercial solid modeling engine underlying CGM and CUBIT, analogous to what's under Pro/E.

## Neutron Streaming through Penetrations

**Neutron streaming through penetrations compromises shielding performance.**
**ARIES-CS 7 types of penetrations**:
- 198 He tubes for blanket (32 cm ID)
- 24 Divertor He access pipes (~30 cm ID)
- 30 Divertor pumping ducts (42 x 120 cm each)
- 12 Large pumping ducts (1 x 1.25 m each)
- 3 ECH ducts (24 x 54 cm each).
- 6 main He pipes - HX to/from blanket  (72 cm ID each)
- 6 main He pipes - HX to/from divertor (70 cm ID each)
**Potential solutions**:
- Local shield behind penetrations
- He tube axis oriented toward lower neutron source
- Penetration shield surrounding ducts
- Replaceable shield close to penetrations
- Rewelding of VV and manifolds avoided close to penetrations
- Bends included in some penetrations.

- √

- √

## Streaming through Blanket He Tubes(9/15/05 Presentation)

- 198 He tubes (30 cm ID) connect manifolds to blanket modules.
**2-D results:**
- High damage at tube wall
- High damage at VV and magnet behind tubes.
**Solutions**:
- Orient tube toward lower n source
- Avoid welding near tube wall
- Replaceable shield close to tube
- Local shield behind tube to protect VV and magnet.

## Streaming through Divertor System

- Streaming through Divertor System

**24 He access pipes**
- (~30 cm ID)

**30 pumping ducts**
- (42 x 120 cm each)

## Streaming through Divertor Pumping Ducts

- Thickness
- (cm)

**20 cm Divertor System**

**Local shield behind ducts needed to protect VV & magnet**

## Effect of Streaming through Divertor He Access Pipes

**NWL** near pipes= 0.5 - 1 MW/m2.
**2-D model** of pipe estimated:
- dpa at shield
- He production at manifolds
- He production at VV
- Fast neutron fluence at WP
- Flux behind pipe
- dpa & He production along pipe wall.
**3-D streaming analysis** is underway using Attila code.

## Part of Shield Surrounding Pipe Should be Replaceable

- 2.2

## Part of Manifolds Surrounding Pipe Cannot be Rewelded

- 48

## Part of VV Surrounding Pipe Cannot be Rewelded

- 43

## 30-40 cm Inter-coil Structure around Pipe Protects Sides of WP

- 230

## High Flux Behind Pipe Calls for Local Shield to Protect Externals

- 104

## Pipe Wall

- Front part of pipe wall
- should be replaceable

- Pipe wall is not reweldable
-  Replace pipe with divertor

- Divertor
- Surface

- Divertor
- Surface

## Recommendations

**Replaceable Shield**

**Not Reweldable**

**Local Shield**

## Ongoing 3-D Streaming Analysis Using Attila Code

**Purpose**: Determine dimensions of replaceable shield,
-                 non-reweldable manifolds and VV, and local shield.

## Alternate Pipe Design(S. Malang)

## Comments on Alternate Pipe Design

- Shielding ring and block do not solved streaming problem entirely:
- 10 cm thick WC **shielding ring** is insufficient to protect pipe wall, bulk shield, and manifolds
-  			    Parts around pipe should be replaceable and cannot be rewelded.
**Shielding block** will not attenuate flux behind pipes by 4 orders of magnitude
-                 	     Local shield behind pipe is still needed.
- Sizable WC shield added:
- 		**Mass / pipe (ton)****	****Alternate Design****	****Baseline Design**
- 			Shielding Ring	~1.6	---
- 			Shielding Block	~1	---
- 			2.5 cm FS Pipe Wall	0.6	0.4
- 		Total mass - 24 pipes 	~77 ton	~10 ton

## LOCA / LOFA Analysis(2.6 MW/m2 Ave. NWL; 0.5 MW/m2 Surface Heat Load)

**Initial temperatures at onset of LOCA/LOFA:**
- 	FW	500 oC 	Shield & Manifolds 	450 oC
- 	SiC	550 oC 	VV	100 oC
- 	Back wall	450 oC 	LiPb average temp 	625 oC
**Assumptions: **Plasma on for 3 s; Instantaneous loss of coolant.

## Uniform Blanket and Shield (He & LiPb LOCA in all Modules; H2O LOFA in VV)

- = 0.3 all surfaces

**Max temp = 753 ****o****C**

**Max temp = 700 ****o****C**

- = 0.5 for SiC

## Non-uniform Blanket and Shield (He & LiPb LOCA in all Modules; H2O LOFA in VV)

- = 0.3 all surfaces

**Max temp = 762 ****o****C**

**Max temp = 720 ****o****C**

- = 0.5 for SiC

## Summary and Conclusions

- 3-D TBR and streaming analyses are underway.
- No shielding ring or block should be included in divertor He access pipes.
- Ongoing 3-D streaming analysis will determine size of replaceable shield and non-reweldble manifolds/VV around pipes.
- More realistic LOCA/LOFA assumptions help reduce temperature during accident.