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Design and performance analysis of structural components for a Korean He Cooled Ceramic Reflector TBM in ITER
Fusion Engineering and Design 88 (2013) 1866–1871
Contents lists available at ScienceDirect
Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes
Design and performance analysis of structural components for a Korean He Cooled Ceramic Reflector TBM in ITER Kyu In Shin a , Dong Won Lee a,∗ , Eo Hwak Lee a , Suk-Kwon Kim a , Jae Sung Yoon a , Seungyon Cho b a b
Korea Atomic Research Institute, Daejeon, Republic of Korea National Fusion Research Institute, Daejeon, Republic of Korea
a r t i c l e
i n f o
Article history: Received 14 November 2012 Received in revised form 30 April 2013 Accepted 13 May 2013 Available online 20 June 2013 Keywords: Allowable stress (Sm ) Helium Cooled Ceramic Reflector (HCCR) RCC-MR code Test Blanket Modules (TBM) Thermal-hydraulic analysis Thermo-mechanical analysis
a b s t r a c t Korea has developed a Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) testing in ITER, which was considered one of the fusion DEMO-relevant blankets in Korea. The design and performance analysis of the TBM body have been carried out considering the uniqueness of the KO TBM and design requirements by the IO and KO design concept: (1) KO TBM has 4 sub-modules considering a post irradiation test (PIE) and its delivery. (2) A first wall (FW) design was changed into a 15 × 11 rectangular shape and its performance was confirmed by thermal-hydraulic and thermo-mechanical analyses using commercial ANSYS code. The results showed that the revised design model satisfied 1.5Sm and 3Sm of the allowable stress (Sm ) in the RCC-MR code at the maximum stress region of the components for mechanical and thermo-mechanical analyses, respectively. (3) Considering the tritium breeding and cooling, a breeding zone (BZ) design was investigated. Three Li and Be layers, and one graphite layer, were proposed by the iteration, and the appropriate temperature distribution was obtained. The design for other components such as a side wall (SW) and back manifold (BM) is on-going considering 9 MPa of channel pressure and its functions of flow distribution as a manifold. © 2013 Elsevier B.V. All rights reserved.
1. Introduction One of the main engineering performance goals of ITER is to test and validate the design concepts of the tritium breeding blankets relevant to a power producing reactor. The tests will focus on modules including a demonstration of the breeding capability that will lead to a tritium self sufficiency and extraction of heat suitable for an electricity generation [1–3]. Korea has developed a Helium Cooled Molten Lithium (HCML) Test Blanket Module (TBM) and Helium Cooled Solid Breeder (HCSB) TBM for testing in the ITER. Recently, solid-type HCSB TBM was decided as a leading concept in the National Fusion Committee and the other is developing as the breeding blanket for DEMO. The name of the solid type TBM was changed to a Helium Cooled Ceramic Reflector (HCCR) considering the unique concept using a graphite reflector [4]. In this study, the overall design procedure of the main components of TBM such as a first wall (FW) and an array of breeding zone (BZ) including its performance analysis was introduced. Until the performance analysis results satisfied the design requirement,
∗ Corresponding author. Tel.: +82 42 868 4659. E-mail address: [email protected] (D.W. Lee). 0920-3796/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fusengdes.2013.05.046
the geometries and arrays of BZ were modified, and finally the optimized design was obtained. 2. Design concept and requirements From the proposed ITER Organization (IO) requirements in the PMG-18-06 meeting (the 6th meeting on Port-18 Management Group), the following were decided: (1) a 15 mm gap from the port frame to TBM, and a 120 mm recession should be considered. Since the port dimension is fixed, the TBM dimension is decided as follows: 1670 mm in height and 462 mm in width. (2) The surface heat flux from plasma side was reduced from 0.5 to 0.35 MW/m2 . Considering the design requirements such as (1) the KO DEMO relevancy, (2) compact size for a delivery for a Post Irradiation Examination (PIE), (3) adopting a graphite reflector, which is a unique concept to replace some of the Be multiplier with cheap and stable in high temperature graphite, and (4) TBR is higher than 1.4 under local assumptions, the conceptual design and basic dimension of the KO TBM was determined, as shown in Fig. 1. The RCC-MR code was used for the design criteria in this study, and classified as the primary and non primary stress in the total stress from the elastic analysis, as shown in Fig. 2 [5,6]. The total stress obtained by an elastic analysis must also be broken down into various stress categories, as shown in Fig. 3. The general primary
K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
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Fig. 3. Various stress categories from a breakdown of stress by elastic analysis according to the RCC-MR code.
Fig. 1. Concept of KO HCCR TBM and its sub-module dimensions.
membrane stress (Pm ) is the mean value of the primary stress within the thickness of the wall, and the primary bending stress (Pb ) is the stress distributed linearly within the thickness, which has the same moment as the primary stress obtained by applying the procedure given in the RCC-MR codes. The local primary membrane stress (PL ) is the stress equal to the sum of stress Pm and Lm : PL = Pm + Lm . Although it does not have all the properties of a primary stress, PL is classified in the primary stress category. And for the stress range evaluation, it should be noted that the sum of the stress intensity of PL (or Pm ) and Pb is PL (or Pm ) + Pb , not the sum of PL (or Pm ) + Pb in the RCC-MR codes. In this study, the equivalent stress according to the Tresca theory was calculated in the mechanical and thermo-mechanical analyses using ANSYS [7]. 3. TBM components design and analyses 3.1. FW design and its performance From the old HCML TBM design, which has a 20 × 10 rectangular U-shape FW, the mechanical analysis considering 9 MPa design pressure was performed. The result showed that the maximum stress in FW was 165 MPa, which was higher than the allowable stress of 123 MPa for RAFM (Reduced Activation Ferritic Martensitic) steel at 500 ◦ C, which is the reference structural material for a KO TBM. Therefore, the channel design needs to be changed to meet the RCC-MR code requirement.
Fig. 4. View of simplified straight FW for a structural analysis.
The simplified straight FW was considered to evaluate the stress, as shown in Fig. 4, where tm is a thickness between the channels, H1 is the width of the channel, H2 is the height of the channel, tp is the thickness from the surface which is directly faced with plasma to the channel, tb is the thickness from the bottom of the channel to a bottom surface in the FW, and R is the curvature in the channel. The mechanical analysis only considered the design pressure, and the thermal analyses were also carried out. The
Fig. 2. Classification of stresses obtained by an elastic analysis according to the RCC-MR code.
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K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
Table 1 Considering the simplified straight FW cases. Case
R
H1
H2
tp
tm
tb
te
max. (MPa)
Temp.max (◦ C)
00 01 02 03 04
2 2 2 4 3
10 10 10 10 11
20 20 20 20 15
3 3 4 3 3
5.5 5 5.5 2.5 6
17 17 16 17 16
3.5 5.5 3.5 3.5 3
157.1 156. 116.5 107.2 74.3
455.7 468.3 468.5 461.5 455.8
considered simplified straight FW cases and maximum Tresca stress and temperature results are summarized in Table 1. Case 00 is the original simplified straight FW case based on the old HCML TBM FW design. The maximum stress of Case 00 was 157.1 MPa and the stress difference between the Case 00 and old HCML TBM FW was only 4.9%. It was noted that the mechanical analysis using the simplified straight FW model can be an allowable method to estimate the stress and determine the revised FW design. Fig. 5 shows Tresca stress and temperature distribution in Case 04 of the simplified straight FW model, and the results give the lowest stress value and an appropriate temperature distribution. Based on the results, the revised FW full model was composed, and the mechanical analysis considering only channel pressure of 9 MPa was conducted to verify the design requirement. The breakdown of the stress result in the revised FW full model showed that Pm was 17.08 MPa and the sum of PL and Pb was 48.78 MPa.
By using the 1.5Sm criterion, the allowable stress (Sm ) of the average temperature (500 ◦ C) is 132 MPa, and the mechanical analysis results considering the channel pressure satisfied the RCC-MR code requirement. According to a change in the FW channel shape, a thermal analysis was conducted and the flow scheme was determined, as shown in Fig. 6. The maximum temperature of the revised FW full model does not exceed 550 ◦ C of the design requirement. In this condition, the flow velocity in a single FW channel is about 50 m/s, and the total mass flow rate is about 1.14 kg/s. For the thermal-structural analysis, two kinds of thermal distribution groups, Group A and B, were considered, as shown in Fig. 6. The results were also evaluated by using the 3Sm criterion. Fig. 7 shows Tresca stress distribution considering the channel pressure and thermal stress in Group A of the revised FW model as the result of a thermal-structural analysis. The maximum stress occurs in the
Fig. 5. Tresca stress and temperature distribution in Case 04 of the simplified straight FW model.
K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
Fig. 6. Flow scheme and temperature distribution of the revised TBM FW.
Fig. 7. Tresca stress distribution considering the channel pressure and thermal stress in Group A of the revised FW model.
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Table 2 Iteration for the optimized KO HCCR TBM design. v0 Case02
v0 Case03
v0 Case04
v0 Case05
v0 Case06
v0 Case07
v1 case06
Remarks
Initial design TLi (2) = 1808 ◦ C 900 ◦ C
Increasing no. of coolant holes (34 → 54) TLi (2): no change
Insert cooling pins in Li zone TLi(2) = 1222 ◦ C 900 ◦ C
Add Li(3) for preserving TBR, Li(1) ∼25mm TLi (2) = 1052 ◦ C 900 ◦ C
Reducing Li(1) ∼20mm TLi (2) = 846 ◦ C < 900 ◦ C
Combined FW with Li(1) ∼20 mm TLi (2) = 846 ◦ C < 900 ◦ C
Combined FW with Be(1) ∼45 mm TLi (2) = 846 ◦ C < 900 ◦ C
Same array case02
Same array case02
Modeling
Analysis results
Same array case02
K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
Iteration Cases
K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
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Fig. 8. Flow scheme and coolant temperature in BZ.
upper channel section in Group A in the revised FW; on the other hand, it occurred in the lower channel section in Group B. The highest stress value is 284.9 MPa in Group A. The primary and secondary stress evaluations at the maximum stress point were assessed along the supporting line segment, which is the thickness of FW channel wall. The allowable stress (Sm ) at the maximum temperature (493 ◦ C) is 139 MPa, and 3Sm is 417 MPa. The sum of the primary and secondary stresses (PL + Pb + Q ) by a thermal-structural analysis is 290.2 MPa, which is lower than 3Sm . In the same way, the highest stress in Group B was 281.8 MPa, and the sum of primary and secondary stresses also satisfied the 3Sm criterion. 3.2. BZ design and its performance Fig. 8 shows the flow scheme and coolant temperature in BZ. The BZ comprises a total of seven layers, i.e., three breeder layers, three multiplier layers, and one reflector layer. A thick graphite reflector is located at the last BZ to maximize its nuclear efficiency. Between the layers, the breeding zone cooling plates with the inside cooling passage are located to cool down each layer in the BZ within the temperature limit. For the design, the ANSYS-CFX analysis was performed and it was checked that the results meet the design requirement. If not, the design was changed. The iteration results are summarized in Table 2, in which the following requirements were considered: (1) the local TBR is higher than 1.4, as evaluated by MCNP, (2) the structure temperature of RAFM steel is below 550 ◦ C evaluated by ANSYS-CFX, and (3) the Li pebble temperature is below 920 ◦ C. In remarks, the results compared with the design requirements were summarized. To obtain the optimized design, seven cases were analyzed. The final design, such as v0-case 06 was determined and the temperature distribution was investigated with the BZ design combined with FW as in the v0-case 07. Finally, the temperature distribution was confirmed using the nuclear heating data with the changed geometry as in v1-case 06.
4. Conclusions To develop the fusion reactor, we have participated in the TBM program in the ITER. According to the recent national decision to
lead the solid-type HCCR TBM, the design and performance analysis for TBM body have been carried out considering the uniqueness of the KO TBM and design requirements by the IO and KO design concept: (1) KO TBM has 4 sub-modules considering PIE and its delivery. (2) The FW design was changed into a 15 × 11 rectangular shape. Through a thermo-mechanical analysis using the commercial ANSYS code, the revised design model satisfied 1.5Sm and 3Sm of the allowable stress (Sm ) in the RCC-MR code at the maximum stress region of the components. (3) For the BZ design, three Li and Be layers, and one graphite layer were proposed by the iteration, and the appropriate temperature distribution was obtained. Considering the functions of SW and BW, such as the flow manifold and assembling part, the flow scheme and mechanical analysis are on-going. Acknowledgment This work was supported by R&D Program through National Fusion Research Institute (NFRI) funded by the Ministry of Education, Science and Technology of the Republic of Korea (NFRIIN1203) References [1] D.W. Lee, B.G. Hong, S.K. Kim, Y. Kim, Design and preliminary safety analysis of a helium cooled molten lithium test blanket module for the ITER in Korea, Fusion Engineering and Design 83 (2008) 1217–1221. [2] D.W. Lee, B.G. Hong, Y. Kim, W.K. In, K.H. Yoon, Preliminary design of a helium cooled molten lithium test blanket module for the ITER test in Korea, Fusion Engineering and Design 82 (2007) 338–381. [3] D.W. Lee, B.G. Hong, Y. Kim, W.K. In, K.H. Yoon, Helium cooled molten lithium TBM for the ITER in Korea, Fusion Science and Technology 52 (2007) 844–848. [4] J.S. Yoon, S.K. Kim, E.H. Lee, S. Cho, D.W. Lee, Fabrication of a 1/6 scale mock-up for the Korea TBM first wall in ITER, Fusion Science and Technology 62 (2012) 29–33. [5] F. Cismondi, S. Kecskes, G. Aiello, HCPB TBM thermo mechanical design: assessment with respect codes and standards and DEMO relevancy, Fusion Engineering and Design 86 (2011) 2228–2232. [6] RCC-MR code, Section 1-Subsection B: Class 1 components, AFCEN, French, 2007. [7] ANSYS, User Manual, ANSYS-Mechanical and CFX, 2012.
Contents lists available at ScienceDirect
Fusion Engineering and Design journal homepage: www.elsevier.com/locate/fusengdes
Design and performance analysis of structural components for a Korean He Cooled Ceramic Reflector TBM in ITER Kyu In Shin a , Dong Won Lee a,∗ , Eo Hwak Lee a , Suk-Kwon Kim a , Jae Sung Yoon a , Seungyon Cho b a b
Korea Atomic Research Institute, Daejeon, Republic of Korea National Fusion Research Institute, Daejeon, Republic of Korea
a r t i c l e
i n f o
Article history: Received 14 November 2012 Received in revised form 30 April 2013 Accepted 13 May 2013 Available online 20 June 2013 Keywords: Allowable stress (Sm ) Helium Cooled Ceramic Reflector (HCCR) RCC-MR code Test Blanket Modules (TBM) Thermal-hydraulic analysis Thermo-mechanical analysis
a b s t r a c t Korea has developed a Helium Cooled Ceramic Reflector (HCCR) Test Blanket Module (TBM) testing in ITER, which was considered one of the fusion DEMO-relevant blankets in Korea. The design and performance analysis of the TBM body have been carried out considering the uniqueness of the KO TBM and design requirements by the IO and KO design concept: (1) KO TBM has 4 sub-modules considering a post irradiation test (PIE) and its delivery. (2) A first wall (FW) design was changed into a 15 × 11 rectangular shape and its performance was confirmed by thermal-hydraulic and thermo-mechanical analyses using commercial ANSYS code. The results showed that the revised design model satisfied 1.5Sm and 3Sm of the allowable stress (Sm ) in the RCC-MR code at the maximum stress region of the components for mechanical and thermo-mechanical analyses, respectively. (3) Considering the tritium breeding and cooling, a breeding zone (BZ) design was investigated. Three Li and Be layers, and one graphite layer, were proposed by the iteration, and the appropriate temperature distribution was obtained. The design for other components such as a side wall (SW) and back manifold (BM) is on-going considering 9 MPa of channel pressure and its functions of flow distribution as a manifold. © 2013 Elsevier B.V. All rights reserved.
1. Introduction One of the main engineering performance goals of ITER is to test and validate the design concepts of the tritium breeding blankets relevant to a power producing reactor. The tests will focus on modules including a demonstration of the breeding capability that will lead to a tritium self sufficiency and extraction of heat suitable for an electricity generation [1–3]. Korea has developed a Helium Cooled Molten Lithium (HCML) Test Blanket Module (TBM) and Helium Cooled Solid Breeder (HCSB) TBM for testing in the ITER. Recently, solid-type HCSB TBM was decided as a leading concept in the National Fusion Committee and the other is developing as the breeding blanket for DEMO. The name of the solid type TBM was changed to a Helium Cooled Ceramic Reflector (HCCR) considering the unique concept using a graphite reflector [4]. In this study, the overall design procedure of the main components of TBM such as a first wall (FW) and an array of breeding zone (BZ) including its performance analysis was introduced. Until the performance analysis results satisfied the design requirement,
∗ Corresponding author. Tel.: +82 42 868 4659. E-mail address: [email protected] (D.W. Lee). 0920-3796/$ – see front matter © 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.fusengdes.2013.05.046
the geometries and arrays of BZ were modified, and finally the optimized design was obtained. 2. Design concept and requirements From the proposed ITER Organization (IO) requirements in the PMG-18-06 meeting (the 6th meeting on Port-18 Management Group), the following were decided: (1) a 15 mm gap from the port frame to TBM, and a 120 mm recession should be considered. Since the port dimension is fixed, the TBM dimension is decided as follows: 1670 mm in height and 462 mm in width. (2) The surface heat flux from plasma side was reduced from 0.5 to 0.35 MW/m2 . Considering the design requirements such as (1) the KO DEMO relevancy, (2) compact size for a delivery for a Post Irradiation Examination (PIE), (3) adopting a graphite reflector, which is a unique concept to replace some of the Be multiplier with cheap and stable in high temperature graphite, and (4) TBR is higher than 1.4 under local assumptions, the conceptual design and basic dimension of the KO TBM was determined, as shown in Fig. 1. The RCC-MR code was used for the design criteria in this study, and classified as the primary and non primary stress in the total stress from the elastic analysis, as shown in Fig. 2 [5,6]. The total stress obtained by an elastic analysis must also be broken down into various stress categories, as shown in Fig. 3. The general primary
K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
1867
Fig. 3. Various stress categories from a breakdown of stress by elastic analysis according to the RCC-MR code.
Fig. 1. Concept of KO HCCR TBM and its sub-module dimensions.
membrane stress (Pm ) is the mean value of the primary stress within the thickness of the wall, and the primary bending stress (Pb ) is the stress distributed linearly within the thickness, which has the same moment as the primary stress obtained by applying the procedure given in the RCC-MR codes. The local primary membrane stress (PL ) is the stress equal to the sum of stress Pm and Lm : PL = Pm + Lm . Although it does not have all the properties of a primary stress, PL is classified in the primary stress category. And for the stress range evaluation, it should be noted that the sum of the stress intensity of PL (or Pm ) and Pb is PL (or Pm ) + Pb , not the sum of PL (or Pm ) + Pb in the RCC-MR codes. In this study, the equivalent stress according to the Tresca theory was calculated in the mechanical and thermo-mechanical analyses using ANSYS [7]. 3. TBM components design and analyses 3.1. FW design and its performance From the old HCML TBM design, which has a 20 × 10 rectangular U-shape FW, the mechanical analysis considering 9 MPa design pressure was performed. The result showed that the maximum stress in FW was 165 MPa, which was higher than the allowable stress of 123 MPa for RAFM (Reduced Activation Ferritic Martensitic) steel at 500 ◦ C, which is the reference structural material for a KO TBM. Therefore, the channel design needs to be changed to meet the RCC-MR code requirement.
Fig. 4. View of simplified straight FW for a structural analysis.
The simplified straight FW was considered to evaluate the stress, as shown in Fig. 4, where tm is a thickness between the channels, H1 is the width of the channel, H2 is the height of the channel, tp is the thickness from the surface which is directly faced with plasma to the channel, tb is the thickness from the bottom of the channel to a bottom surface in the FW, and R is the curvature in the channel. The mechanical analysis only considered the design pressure, and the thermal analyses were also carried out. The
Fig. 2. Classification of stresses obtained by an elastic analysis according to the RCC-MR code.
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K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
Table 1 Considering the simplified straight FW cases. Case
R
H1
H2
tp
tm
tb
te
max. (MPa)
Temp.max (◦ C)
00 01 02 03 04
2 2 2 4 3
10 10 10 10 11
20 20 20 20 15
3 3 4 3 3
5.5 5 5.5 2.5 6
17 17 16 17 16
3.5 5.5 3.5 3.5 3
157.1 156. 116.5 107.2 74.3
455.7 468.3 468.5 461.5 455.8
considered simplified straight FW cases and maximum Tresca stress and temperature results are summarized in Table 1. Case 00 is the original simplified straight FW case based on the old HCML TBM FW design. The maximum stress of Case 00 was 157.1 MPa and the stress difference between the Case 00 and old HCML TBM FW was only 4.9%. It was noted that the mechanical analysis using the simplified straight FW model can be an allowable method to estimate the stress and determine the revised FW design. Fig. 5 shows Tresca stress and temperature distribution in Case 04 of the simplified straight FW model, and the results give the lowest stress value and an appropriate temperature distribution. Based on the results, the revised FW full model was composed, and the mechanical analysis considering only channel pressure of 9 MPa was conducted to verify the design requirement. The breakdown of the stress result in the revised FW full model showed that Pm was 17.08 MPa and the sum of PL and Pb was 48.78 MPa.
By using the 1.5Sm criterion, the allowable stress (Sm ) of the average temperature (500 ◦ C) is 132 MPa, and the mechanical analysis results considering the channel pressure satisfied the RCC-MR code requirement. According to a change in the FW channel shape, a thermal analysis was conducted and the flow scheme was determined, as shown in Fig. 6. The maximum temperature of the revised FW full model does not exceed 550 ◦ C of the design requirement. In this condition, the flow velocity in a single FW channel is about 50 m/s, and the total mass flow rate is about 1.14 kg/s. For the thermal-structural analysis, two kinds of thermal distribution groups, Group A and B, were considered, as shown in Fig. 6. The results were also evaluated by using the 3Sm criterion. Fig. 7 shows Tresca stress distribution considering the channel pressure and thermal stress in Group A of the revised FW model as the result of a thermal-structural analysis. The maximum stress occurs in the
Fig. 5. Tresca stress and temperature distribution in Case 04 of the simplified straight FW model.
K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
Fig. 6. Flow scheme and temperature distribution of the revised TBM FW.
Fig. 7. Tresca stress distribution considering the channel pressure and thermal stress in Group A of the revised FW model.
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Table 2 Iteration for the optimized KO HCCR TBM design. v0 Case02
v0 Case03
v0 Case04
v0 Case05
v0 Case06
v0 Case07
v1 case06
Remarks
Initial design TLi (2) = 1808 ◦ C 900 ◦ C
Increasing no. of coolant holes (34 → 54) TLi (2): no change
Insert cooling pins in Li zone TLi(2) = 1222 ◦ C 900 ◦ C
Add Li(3) for preserving TBR, Li(1) ∼25mm TLi (2) = 1052 ◦ C 900 ◦ C
Reducing Li(1) ∼20mm TLi (2) = 846 ◦ C < 900 ◦ C
Combined FW with Li(1) ∼20 mm TLi (2) = 846 ◦ C < 900 ◦ C
Combined FW with Be(1) ∼45 mm TLi (2) = 846 ◦ C < 900 ◦ C
Same array case02
Same array case02
Modeling
Analysis results
Same array case02
K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
Iteration Cases
K.I. Shin et al. / Fusion Engineering and Design 88 (2013) 1866–1871
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Fig. 8. Flow scheme and coolant temperature in BZ.
upper channel section in Group A in the revised FW; on the other hand, it occurred in the lower channel section in Group B. The highest stress value is 284.9 MPa in Group A. The primary and secondary stress evaluations at the maximum stress point were assessed along the supporting line segment, which is the thickness of FW channel wall. The allowable stress (Sm ) at the maximum temperature (493 ◦ C) is 139 MPa, and 3Sm is 417 MPa. The sum of the primary and secondary stresses (PL + Pb + Q ) by a thermal-structural analysis is 290.2 MPa, which is lower than 3Sm . In the same way, the highest stress in Group B was 281.8 MPa, and the sum of primary and secondary stresses also satisfied the 3Sm criterion. 3.2. BZ design and its performance Fig. 8 shows the flow scheme and coolant temperature in BZ. The BZ comprises a total of seven layers, i.e., three breeder layers, three multiplier layers, and one reflector layer. A thick graphite reflector is located at the last BZ to maximize its nuclear efficiency. Between the layers, the breeding zone cooling plates with the inside cooling passage are located to cool down each layer in the BZ within the temperature limit. For the design, the ANSYS-CFX analysis was performed and it was checked that the results meet the design requirement. If not, the design was changed. The iteration results are summarized in Table 2, in which the following requirements were considered: (1) the local TBR is higher than 1.4, as evaluated by MCNP, (2) the structure temperature of RAFM steel is below 550 ◦ C evaluated by ANSYS-CFX, and (3) the Li pebble temperature is below 920 ◦ C. In remarks, the results compared with the design requirements were summarized. To obtain the optimized design, seven cases were analyzed. The final design, such as v0-case 06 was determined and the temperature distribution was investigated with the BZ design combined with FW as in the v0-case 07. Finally, the temperature distribution was confirmed using the nuclear heating data with the changed geometry as in v1-case 06.
4. Conclusions To develop the fusion reactor, we have participated in the TBM program in the ITER. According to the recent national decision to
lead the solid-type HCCR TBM, the design and performance analysis for TBM body have been carried out considering the uniqueness of the KO TBM and design requirements by the IO and KO design concept: (1) KO TBM has 4 sub-modules considering PIE and its delivery. (2) The FW design was changed into a 15 × 11 rectangular shape. Through a thermo-mechanical analysis using the commercial ANSYS code, the revised design model satisfied 1.5Sm and 3Sm of the allowable stress (Sm ) in the RCC-MR code at the maximum stress region of the components. (3) For the BZ design, three Li and Be layers, and one graphite layer were proposed by the iteration, and the appropriate temperature distribution was obtained. Considering the functions of SW and BW, such as the flow manifold and assembling part, the flow scheme and mechanical analysis are on-going. Acknowledgment This work was supported by R&D Program through National Fusion Research Institute (NFRI) funded by the Ministry of Education, Science and Technology of the Republic of Korea (NFRIIN1203) References [1] D.W. Lee, B.G. Hong, S.K. Kim, Y. Kim, Design and preliminary safety analysis of a helium cooled molten lithium test blanket module for the ITER in Korea, Fusion Engineering and Design 83 (2008) 1217–1221. [2] D.W. Lee, B.G. Hong, Y. Kim, W.K. In, K.H. Yoon, Preliminary design of a helium cooled molten lithium test blanket module for the ITER test in Korea, Fusion Engineering and Design 82 (2007) 338–381. [3] D.W. Lee, B.G. Hong, Y. Kim, W.K. In, K.H. Yoon, Helium cooled molten lithium TBM for the ITER in Korea, Fusion Science and Technology 52 (2007) 844–848. [4] J.S. Yoon, S.K. Kim, E.H. Lee, S. Cho, D.W. Lee, Fabrication of a 1/6 scale mock-up for the Korea TBM first wall in ITER, Fusion Science and Technology 62 (2012) 29–33. [5] F. Cismondi, S. Kecskes, G. Aiello, HCPB TBM thermo mechanical design: assessment with respect codes and standards and DEMO relevancy, Fusion Engineering and Design 86 (2011) 2228–2232. [6] RCC-MR code, Section 1-Subsection B: Class 1 components, AFCEN, French, 2007. [7] ANSYS, User Manual, ANSYS-Mechanical and CFX, 2012.