# Thermomechanical and Thermofluid-Dynamic Coupled Analysis of the Top Cap Region of the Water-Cooled Lithium Lead Breeding Blanket for the EU DEMO Fusion Reactor

^{1}

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## Abstract

**:**

## 1. Introduction

## 2. The DEMO Water-Cooled Lithium Lead Breeding Blanket Concept

^{2}cross-section following a radial–toroidal–radial path. The channels are fed in countercurrent by means of a proper manifold system. It has to be added that the FW-SW is covered by a 2 mm-thick tungsten armor aimed at protecting the plasma from impurities.

^{2}section. The main reason behind the increased thickness with respect to the FW one is the withstanding of pressure arising in case of accident. In the end, it has to be recalled that the complex of FW-SW, BPs, Manifolds, Caps, and BSS is called Segment Box (SB). It is usual to refer to the SPs grid as a reinforcement component for the SB.

#### The Top Cap Region of the DEMO WCLL BB COB Segment

## 3. The 3D Geometric Model

## 4. The Thermofluid-Dynamic Analysis

#### 4.1. The Adopted Methodology

#### 4.2. The Preliminary Assessment of the Fluid Dynamics in the FW and BZ Cooling Circuits

#### 4.2.1. The Spatial Discretization

#### 4.2.2. Assumptions, Loads and Boundary Conditions

#### 4.2.3. The Obtained Results

#### 4.3. Thermofluid-Dynamic Analysis of the Top Cap Region

#### 4.3.1. The Spatial Discretization

#### 4.3.2. Assumptions, Loads, and Boundary Conditions

^{2}on the straight part of the FW, which was therefore applied to this zone, in agreement with the modelling strategy applied in [7]. However, as obvious, this heat flux progressively decreases down to zero on the curved surfaces of the FW, and a cosine law has been selected to describe this variation. Concerning the heat deposited by fusion neutrons, volumetric heat loads curves from [13] have been adopted, while regarding the interaction between the structures and the water a simple conservative heat transfer interface condition has been selected. Finally, the external surfaces of the TC region were assumed to be adiabatic, according to the hypothesis that, in steady-state operation of the reactor, these parts of the structure reach thermal equilibrium with the surrounding other blanket segments, while the BSS has been conservatively set as adiabatic. Regarding the structural and functional material properties, temperature-dependent values have been selected for Eurofer [14], tungsten [15], and PbLi [16]. Temperature and pressure-dependent properties have been used for water too [9].

#### 4.3.3. The Obtained Results

## 5. Comparison of the Thermal Analyses Results

## 6. The Thermomechanical Analysis

#### 6.1. The Adopted Methodology

#### 6.2. The Spatial Discretisation

#### 6.3. Loads and Boundary Conditions

#### 6.4. The Obtained Results

_{m}+ P

_{b}+ Q + F)/S

_{et}) is met with a very narrow margin along the paths SB2_A and SB9_A.

## 7. Comparison of the Thermomechanical Analyses Results

## 8. Conclusions

## Author Contributions

## Funding

## Data Availability Statement

## Conflicts of Interest

## References

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**Figure 17.**Statistical distributions of the temperature deviation and cumulative curves for FW-SW (

**a**), TC (

**b**) and SPs (

**c**).

**Figure 24.**Statistical distributions of the stress deviations and cumulative curves in the FW-SW for normal (

**a**) and shear (

**b**) components.

**Figure 25.**Statistical distributions of the stress deviations and cumulative curves in the SPs for normal (

**a**) and shear (

**b**) components.

**Figure 26.**Statistical distributions of the stress deviations and cumulative curves in the TC for normal (

**a**) and shear (

**b**) components.

Mass Flow Rate [kg/s] | |||
---|---|---|---|

FW1 | FW2 | BZ | |

Outlet entrance | 17.08 | 16.64 | 125.41 |

Outlet exit | 17.75 | 17.75 | 127.80 |

Path | P_{m}/S_{m} | (P_{m} + P_{b})/(K_{eff} * S_{m}) | (P_{m} + Q_{m})/S_{em} | (P_{m} + P_{b} + Q + F)/S_{et} |
---|---|---|---|---|

TC3_A | 0.0698 | 0.0786 | 0.6203 | 0.1958 |

TC3_B | 0.1419 | 0.1000 | 0.4063 | 0.1344 |

TC3_C | 0.0713 | 0.1003 | 0.2858 | 0.2174 |

TC8_A | 0.1592 | 0.1691 | 0.2540 | 0.1116 |

TC8_B | 0.1891 | 0.1735 | 0.4298 | 0.1307 |

TC8_C | 0.0994 | 0.0892 | 0.2427 | 0.0830 |

SB2_A | 0.1550 | 0.1236 | 0.5000 | 0.9661 |

SB2_B | 0.1720 | 0.1698 | 0.6187 | 0.2010 |

SB2_C | 0.0810 | 0.1300 | 0.3385 | 0.7831 |

SB9_A | 0.0863 | 0.0667 | 0.4730 | 0.9805 |

SB9_B | 0.0574 | 0.0599 | 0.4429 | 0.1144 |

SB9_C | 0.0656 | 0.0555 | 0.3060 | 0.7491 |

Path | P_{m}/S_{m} | (P_{m} + P_{b})/(K_{eff} * S_{m}) | (P_{m} + Q_{m})/S_{em} | (P_{m} + P_{b} + Q + F)/S_{et} |
---|---|---|---|---|

TC3_A | 0.0680 | 0.0771 | 0.4823 | 0.1619 |

TC3_B | 0.1378 | 0.0971 | 0.5171 | 0.2053 |

TC3_C | 0.0694 | 0.0969 | 0.4343 | 0.1735 |

TC8_A | 0.1576 | 0.1673 | 0.2314 | 0.1219 |

TC8_B | 0.1872 | 0.1718 | 0.4316 | 0.1416 |

TC8_C | 0.0983 | 0.0882 | 0.2385 | 0.0890 |

SB2_A | 0.1538 | 0.1227 | 0.5237 | 0.9956 |

SB2_B | 0.1722 | 0.1697 | 0.5259 | 0.1928 |

SB2_C | 0.0809 | 0.1299 | 0.2847 | 0.8002 |

SB9_A | 0.0865 | 0.0667 | 0.5606 | 1.0798 |

SB9_B | 0.0570 | 0.0601 | 0.4540 | 0.1523 |

SB9_C | 0.0644 | 0.0544 | 0.2485 | 0.7643 |

Path | P_{m}/S_{m} | (P_{m} + P_{b})/(K_{eff} * S_{m}) | (P_{m} + Q_{m})/S_{em} | (P_{m} + P_{b} + Q + F)/S_{et} |
---|---|---|---|---|

TC3_A | +2.6% | +2.0% | +28.6% | +20.9% |

TC3_B | +2.9% | +3.0% | −21.4% | −34.5% |

TC3_C | +2.7% | +3.6% | −34.2% | +25.3% |

TC8_A | +1.0% | +1.1% | +9.7% | −8.5% |

TC8_B | +1.0% | +1.0% | −0.4% | −7.7% |

TC8_C | +1.0% | +1.1% | +1.8% | −6.8% |

SB2_A | +0.8% | +0.7% | −4.5% | −3.0% |

SB2_B | −0.1% | +0.1% | +17.6% | +4.2% |

SB2_C | +0.2% | +0.0% | +18.9% | −2.1% |

SB9_A | −0.2% | +0.0% | −15.6% | −9.2% |

SB9_B | +0.8% | −0.4% | −2.4% | −24.8% |

SB9_C | +1.9% | +2.0% | +23.1% | −2.0% |

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**MDPI and ACS Style**

Gioè, A.; Bongiovì, G.; Catanzaro, I.; Chiovaro, P.; Di Maio, P.A.; Giambrone, S.; Quartararo, A.; Vallone, E.; Arena, P.; Basile, S.
Thermomechanical and Thermofluid-Dynamic Coupled Analysis of the Top Cap Region of the Water-Cooled Lithium Lead Breeding Blanket for the EU DEMO Fusion Reactor. *Energies* **2023**, *16*, 3249.
https://doi.org/10.3390/en16073249

**AMA Style**

Gioè A, Bongiovì G, Catanzaro I, Chiovaro P, Di Maio PA, Giambrone S, Quartararo A, Vallone E, Arena P, Basile S.
Thermomechanical and Thermofluid-Dynamic Coupled Analysis of the Top Cap Region of the Water-Cooled Lithium Lead Breeding Blanket for the EU DEMO Fusion Reactor. *Energies*. 2023; 16(7):3249.
https://doi.org/10.3390/en16073249

**Chicago/Turabian Style**

Gioè, Alberto, Gaetano Bongiovì, Ilenia Catanzaro, Pierluigi Chiovaro, Pietro Alessandro Di Maio, Salvatore Giambrone, Andrea Quartararo, Eugenio Vallone, Pietro Arena, and Salvatore Basile.
2023. "Thermomechanical and Thermofluid-Dynamic Coupled Analysis of the Top Cap Region of the Water-Cooled Lithium Lead Breeding Blanket for the EU DEMO Fusion Reactor" *Energies* 16, no. 7: 3249.
https://doi.org/10.3390/en16073249