Design evaluation on sodium piping system and ... - Springer Link

Journal of Mechanical Science and Technology 29 (3) (2015) 1019~1027 www.springerlink.com/content/1738-494x

DOI 10.1007/s12206-015-0216-9

Design evaluation on sodium piping system and comparison of the design codes† Dong-Won Lee, Ji-Young Jeong, Yong-Bum Lee and Hyeong-Yeon Lee* Korea Atomic Energy Research Institute, 989-111 Daedeok-Daero, Yuseong-gu, Daejeon, 305-353, Korea (Manuscript Received July 19, 2014; Revised November 5, 2014; Accepted November 20, 2014) ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

Abstract A large-scale sodium test loop of STELLA-1 (Sodium integral effect test loop for safety simulation and assessment) with two main piping systems has been installed at KAERI. In this study, design evaluations on the main sodium piping systems in STELLA-1 have been conducted according to the DBR (design by rule) codes of the ASME B31.1 and RCC-MRx RB-3600. In addition, design evaluations according to the DBA (design by analysis) code of the ASME Section III Subsection NB-3200 have been conducted. The evaluation results for the present piping systems showed that results from the DBR codes were more conservative than those from the DBA code, and among the DBR codes, the non-nuclear code of the ASME B31.1 was more conservative than the French nuclear DBR code of the RCC-MRx RB-3600. The conservatism on the DBR codes of the ASME B31.1 and RCC-MRx RB-3600 was quantified based on the present sodium piping analyses. Keywords: Design code; Design by rule; Design by analysis; Piping system; Design evaluation ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------

1. Introduction Because reliable decay heat removal after a reactor shutdown is very crucial in a generation IV (Gen IV) sodiumcooled fast reactor (SFR) design, the decay heat removal system (DHRS) is classified as a safety-grade system in an SFR. The Korea Atomic Energy Research Institute (KAERI) has constructed a sodium test loop of STELLA-1 (Sodium integral effect test loop for safety simulation and assessment) for the component performance tests of heat exchangers and a mechanical pump [1]. The large sodium test facility with a sodium inventory of 18 tons is intended for verification and validation (V&V) of computer codes for thermal hydraulic design on the decay heat removal behavior of the Korean prototype SFR [2] and performance tests of the heat exchangers and mechanical sodium pump. In this study, integrity evaluations of the main piping system in the STELLA-1 sodium test loop were conducted according to the design guidelines of the design by rule (DBR) codes and design by analysis (DBA) code. The design guidelines of the DBR applied in this study are the French code of the RCC-MRx RB-3600 [3] and ASME B31.1 [4], while the design guidelines of DBA applied in this study are ASME Section III Subsection NB-3200 [5]. Design evaluations according to DBR codes were conducted using pipe element modeling, while those according to the DBA code were con*

Corresponding author. Tel.: +82 42 868 2956, Fax.: +82 42 868 8739 E-mail address: [email protected] † Recommended by Editor Chongdu Cho © KSME & Springer 2015

ducted with 3D solid element modeling in a finite element analysis. It is generally known that the DBR code using a simple formula is more conservative than the DBA code using a detailed finite element analysis. In this study, the evaluation results from the DBR codes of ASME B31.1 and RCC-MRx3600 were compared to those from the DBA code of ASME NB-3200 to quantify the conservatism. In addition, the conservatism of the two DBR codes (ASME B31.1 and RCCMRx-3600) was quantified. The three design evaluation results showed that the integrity of the main piping system is maintained under the intended design basis load conditions. Design evaluations according to the DBA codes were conducted for the main components in STELLA-1. Design evaluations for a sodium-to-sodium heat exchanger (decay heat exchanger: DHX [6]), a helical tube type sodium-to-air heat exchanger (AHX [7, 8]) and a finned-tube sodium-to-air heat exchanger (FHX [8, 9]) were conducted according to the elevated temperature DBA codes of the ASME Section III Subsection NH [10] and RCC-MRx RB-3200 [3]. From the design evaluations, ASME Subsection NH was generally shown to be more conservative than RCC-MRx. Consequently, the integrity of the main components and piping systems of STELLA-1 was confirmed from those evaluations.

2. Piping systems in the STELLA-1 sodium test loop The reference reactor of the sodium test facility, STELLA-1 is a Korean prototype SFR [2]. The height and length scale of

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D.-W. Lee et al. / Journal of Mechanical Science and Technology 29 (3) (2015) 1019~1027

Fig. 3. Main piping system 2.

Fig. 1. Schematic of the STELLA-1 loop.

(a) Design basis condition

Fig. 2. Main piping system 1.

the STELLA-1 facility against the prototype reactor is 1/5, the working fluid is sodium, and the maximum simulated core power is 1% of the scaled nominal power. A schematic of the STEELA-1 loop is shown in Fig. 1. The 10-inch (10”SCH40S) main piping systems in Figs. 2 and 3 connecting the reservoir tank and mechanical sodium pump are the target piping systems to be evaluated in this study. The material of the main piping is austenitic stainless steel 316L. Unlike the heat exchangers of DHX and AHX in the STELLA-1 loop operating at the creep regime, the design temperature of the sodium piping has been limited under 370.2°C because DHX in the reference reactor is located in a cold pool. Therefore, creep was not taken into account in the design and evaluation of the present piping systems.

3. Design evaluations of the main sodium piping system 3.1 Finite element modeling Finite element analyses for the main piping systems were conducted with pipe elements and solid elements of ANSYS [11]. For the design by rule (DBR) analysis according to RCC-MRx RB-3600 and ASME B31.1, piping analyses using ANSYS pipe elements were conducted for the main piping system number 1

(b) Design extended condition Fig. 4. Thermal loading conditions of sodium test loop piping.

of Fig. 2, and piping system number 2 of Fig. 3. For the design by analysis (DBA) according to ASME NB3200, 3D finite element analyses for the two piping systems were conducted using solid elements. The design conditions on the thermal loading of the two piping analyses are shown in Fig. 4. Fig. 4(a) is the design transient in the design basis condition, while Fig. 4(b) is the transient in design extended conditions. The design extended condition for the present analysis was assumed to be the limiting thermal condition that the sodium temperature inside the main piping is the same with hot pool sodium temperature of 545°C. The two transients in Fig. 4 are composed of five loading steps: steady state at 370.2°C (or 545°C), cool-down to 200°C with a cool-down rate of 100°C/hr, heat-up to 370.2°C (or

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Table 1. Design by rule evaluation results as per RCC-MRx RB-3600.

Piping system 1

Piping system 2

Code equation

Calculated(1) (MPa)

Code allowable(2) (MPa)

Ratio (%) (1)/(2)

Eq. (9)

34.1

140.9

24.2%

Eq. (10)

61.5

183.2

33.6%

Eq. (11)

127.3

325.2

39.1%

Eq. (9)

37.7

140.9

26.8%

Eq. (10)

83.7

183.2

45.7%

Eq. (11)

165

325.2

50.7%

Fig. 5. Distribution of stress intensities in piping system 1 (unit : Pa).

stress range of the main piping systems in RB 3661.1 is given by Eq. (1) [3]. q ( j , j¢) = áC2 / Z , m( j , j¢)ñ + Eaq1 ( j , j¢ ) / 2(1 - n ) + C3 ( Eaa aq ma - Eba bq mb )( j , j¢ )


545°C), and finally reaching a steady steate at 370.2°C (or 545°C). The design pressure of 1.0 MPa and mechanical loads including deadweights of the piping, sodium, valve, and instruments were taken into account.

where C2 and C3 are stress factors for the piping element of concern, Z is the modulus of inertia, E is Young’s modulus, α is coefficient of thermal expansion, n is the Poisson ratio, q1 is the temperature characterizing the linear temperature gradient in the thickness of the wall, and q ma and q mb are the mean values of the mean temperature gradient in the thickness of the wall. To obtain the effective primary stress intensity, the two secondary ratios of SR1 and SR2 are calculated as in Eqs. (2) and (3). The two ratios were calculated at the critical location of the bottom anchor point in Fig. 5. SR1 =

Max q ( j , j¢)

SR2 =

(2)

Max pm

3.2 ‘Design by rule’ evaluation 3.2.1 Design basis condition Design by rule evaluations on the design basis condition of Fig. 4(a) were conducted according to the RCC-MRx Code (RB-3600) and ASME code (B31.1) for the main piping system number 1 (Fig. 2) and piping system number 2 (Fig. 3) using the ANSYS results. RCC-MRx [3] is a French elevated temperature design code for high-temperature nuclear systems and components, such as the French SFR prototype of the ASTRID and fusion reactor of the ITER. RCC-MRx RB-3600 is the class I ‘design by rule’ piping code. In the meantime, the ASME B31.1 code is a non-nuclear ‘design by rule’ pressure piping code. In this study, the conservatism in RB-3600 and ASME B31.1 has been quantified based on the DBR analysis for the present piping systems. Figs. 5 and 6 show the stress intensities of the main piping systems at the end of the heat-up in the design basis conditions of Fig. 4(a). It was shown that the stress intensities are larger in piping system number 2 compared to number 1. As for the analysis according to RCC-MRx RB-3600, the

(1)

Max q ( j , j¢) Max pm + pb

.

(3)

Efficiency indices of V1 and V2 are obtained using the efficiency diagram in RB 3661.12. SR £ 0.46 0.46 < SR < 4

V =1

SR ³ 4

V = 1 / SR .

V = 1.093 - 0.926 SR 2 / (1 + SR ) 2 (4)

Then, the effective primary stress intensities are determined as follows.

p1 =

Max pm V1

(5)

p2 =

Max pm + pb V2

(6)

Pm = p ( De - 2 yh) / 2h

(7)

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Table 2. Design by rule evaluation results as per ASME B31.1.

Piping system 1

Piping system 2

Code equation

Calculated(1) (MPa)


Ratio (%) (1)/(2)

Eq. (12)

23.5

110.3

21.3%

Eq. (13)

23.5

132.4

17.7%

Eq. (14)

100.9

258.3

39.1%

Eq. (12)

56.1

110.3

50.9%

Eq. (13)

56.1

132.4

42.4%

Eq. (14)

156

225.7

69.1% Fig. 7. Distribution of stress intensities in piping system 1 (unit : Pa).

Pm + Pb = B1 * P

De + B2 / Z , M . 2hc

(8)

The effective primary stress intensities of p1 and p2 should not exceed 1.3Sm and 1.69Sm, respectively, as shown in Eqs. (9) and (10), and the calculation results show that the requirements were satisfied, as shown in Table 1. P1 £ 1.3Sm P2 £ 1.69 Sm .

(9) (10)

In addition, RB-3600 requires that the shakedown rule shown in Eq. (11) should be satisfied. The evaluation results show that Eq. (11) is satisfied, as shown in Table 1. Max( Pm + Pb ) + Maxq ( j , j¢) £ 3Sm .

(11)

The analysis results as per RCC-MRx RB-3600 for both piping systems show that all design limits were satisfied, as shown in Table 1. As for the design evaluation as per the ASME pressure piping code B31.1 [4], ASME B31.1 requires three equations to be satisfied. The first one is that Eq. (12) from sustained loads under pressure, weight, and other sustained mechanical loads shall be satisfied. SL =

PDO 0.75iM A + £ 1.0 Sh , (1000)4tn Z

(12)

where i is the stress intensification factor, and MA is the resultant moment loading on the cross section due to the weight and other sustained loads. The second one requires that Eq. (13) from occasional loads under pressure, weight, other sustained loads, and occasional loads including earthquakes should be met. PDO 0.75iM A 0.75iM B + + £ kSh . (1000)4tn Z Z

(13)

The third one requires that stress from displacement load ranges under thermal expansion and other cyclic loads should meet the requirements of Eq. (14).


SE =

1000(iM C ) £ SA , Z

(14)

where Mc is resultant moment loading range on the cross section owing to the reference displacement load range. The design evaluation results as per the ASME B31.1 code are shown in Table 2, which shows that the stresses calculated according to the above three equations were well within the allowable code limits. In the case of an elevated temperature design evaluation on a piping system, creep damage and creep-fatigue damage are not explicitly considered in the ASME B31.1 code, while they are explicitly considered in the RCC-MRx RB 3600. In Eq. 12B of ASME B31.1 [4], occasional loads of no more than eight hours are taken into account. From the above design evaluations in the design basis condition according to the RB-3600 and ASME B31.1, it was shown that the present piping systems maintain integrity with sufficient margins, as shown in Table 2 under the intended mechanical and thermal load conditions. 3.2.2 Design extended condition Design by rule evaluations under design extended condition were also conducted according to RB-3600 and ASME B31.1 for the main piping system number 1 (Fig. 7) and piping system number 2 (Fig. 8) to compare the conservatism of the RB3600 and ASME B31.1.


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Table 3. Design by rule evaluation for design extended condition. Code equation

Calculated(1) (MPa)


Ratio (%) (1)¸(2)

Piping system 1

Eq. (11)

189.5

299.3

63.3%

Eq. (14)

228

244.9

93.1%

Piping system 2

Eq. (11)

205.5

299.3

68.7%

Eq. (14)

274.9

212.3

129.5%

Figs. 7 and 8 show the stress intensities of the main piping systems under the design extended conditions of Fig. 4(b). The loading conditions of the design basis condition are different from the design extended condition only for thermal transient conditions, as shown in Figs. 4(a) and (b). Therefore, the loading conditions for the two conditions under primary load are the same, and the design evaluation upon primary loading is not necessary. From the above evaluations for the design extended condition as per the RCC-MRx RB-3600 and ASME B31.1, piping system 1 maintains integrity as shown in Table 3 for this design extended condition based on the design evaluation according to RB-3600 of Eq. (11) and ASME B31.1 of Eq. (14). However, piping system 2 maintains integrity only for the case of RB-3600, but not for the case of the ASME B31.1 as shown in Table 3. This means that B31.1 is more conservative than RB-3600 when comparing the two DBR codes.

Fig. 9. Boundary conditions for solid model in piping system 1.

Fig. 10. Boundary conditions for solid model in piping system 2.

3.3 ‘Design by analysis’ evaluation 3.3.1 Design basis condition The design by analysis (DBA) code of the ASME Section III Subsection NB-3200 (ASME NB-3200) has been employed for the design evaluation of the piping systems based on a 3D finite element analysis. The evaluation results according to the DBA code were compared to those according to the DBR code evaluations to compare the conservatism of the codes. In this DBA procedure, a heat transfer analysis and thermal stress analysis for the piping system with 3D finite element model were conducted. The ANSYS [11] finite element model for the 1 piping system is composed of 229,948 3D linear solid elements and 78,170 nodes, while that for the 2 piping system is composed of 368,044 3D linear solid elements and 124,041 nodes. The boundary conditions for piping system 1 and 2 are shown in Figs. 9 and 10, respectively. The ends of the piping systems were assumed to be fixed, while thermal expansions in the radial direction were allowed. In addition, the supporting points in the support structure were completely fixed, while the supporting points were set free in the radial direction. A heat transfer analysis has been conducted for the design basis condition of Fig. 4(a). The temperature distributions at the end of the heat-up are shown in Figs. 11 and 12 for the two piping systems. The maximum temperature occurred at the

Fig. 11. Temperature distribution of piping 1 at the end of heat-up.

inner surface of the piping system. The components of the valve and flange in the piping system showed low temperature distributions. A stress analysis on the piping systems for a design basis condition has been performed considering the thermal load, dead load, and internal pressure. Stress analyses under mechanical loads, and a stress analysis under primary and secondary loads, were conducted. The end points of the two piping systems were connected to the mechanical pump and reservoir tank. The primary stress and secondary stress results are shown from Figs. 13-16. The maximum von Mises stress intensity for the 1 piping system was calculated as 15.703 (MPa) under the primary load only, and 110.46 (MPa) under the secondary load only. The maximum Mises stress of the 2 piping system was calculated as 58.737 (MPa) under the primary load only and 131.87 (MPa) under the secondary load only. The results from solid element analyses were slightly different from those from piping ele-

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Table 4. Design by analysis evaluation results as per ASME NB-3200 for piping system 1. Evaluation items

Calculated(1) (MPa)


Pm

16.2

110.3

14.7%

PL + Pb

17.5

165.5

10.6%

Ratio (%), (1)/(2)

Primary stress limits

Secondary stress limit PL + Pb + Pe + Q Fig. 12. Temperature distribution of piping 2 at the end of heat-up.

124.3

330.9

37.6%

Table 5. Design by analysis evaluation results as per ASME NB-3200 for piping system 2. Evaluation items

Calculated(1) (MPa)


Pm

12.9

110.3

11.7%

PL + Pb

61.7

165.5

37.3%

PL + Pb + Pe + Q

134.2

Ratio (%), (1)/(2)

Primary stress limits

Secondary stress limit 330.9

40.6%

Fig. 13. Distribution of primary stress in piping system 1.

Fig. 16. Distribution of secondary stress in piping system 1(unit : Pa).

Fig. 14. Distribution of secondary stress in piping system 1.

Fig. 15. Distribution of primary stress in piping system 2 (unit : Pa).

ment analyses, while the maximum stress intensity occurred at nearly the same location. The analysis results according to the ASME NB-3200 are shown in Tables 4 and 5. For the analysis according to ASME NB-3200, the calculated membrane stress intensity of Pm under the primary load should not exceed Sm. In addition, the calculated membrane plus local bending stress intensity of PL+Pb under primary loads should not exceed 1.5Sm, and finally, the calculated primary membrane plus bending plus thermal expansion stress of PL+Pb+Pe+Q under primary and secondary loads should not exceed 3Sm. From the above design evaluations according to the ASME NB-3200, the present main piping systems maintain the structural integrity in terms of load-controlled stress limits under the intended design basis condition of Fig. 4(a). 3.3.2 Design extended condition Design by analysis evaluations for design extended condi-

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Table 6. Design by analysis evaluation results in design extended condition as per ASME NB-3200. Calculated(1) (MPa)


Ratio (%) (1)/(2)

Piping PL + Pb + Pe + system 1 Q

186.8

298.7

62.5%

Piping PL + Pb + Pe + system 2 Q

199.3

298.7

66.7%

Evaluation items


Fig. 19. Distribution of secondary stress in piping system 1(unit : Pa).


tion of Fig. 4(b) were conducted according to the ASME Section III Subsection NB-3200 (ASME NB-3200) for the main piping systems 1 and 2. A heat transfer analysis for the design extended condition of Fig. 4(b) was conducted. The temperature distributions at the end of the heat-up for the two piping systems are shown in Figs. 17 and 18. A stress analysis of the piping systems for the design extended conditions has been performed as in the design basis event. Since there is only a change in thermal load, the results of the primary stress in the design extended conditions are the same with those of the design basis event. Secondary stress results are shown in Figs. 19 and 20. A maximum von Mises stress intensity for the 1 piping system was calculated as 165.92 (MPa) under the secondary load only. A maximum von Mises stress of the 2 piping system was calculated as 183.72 (MPa) under the secondary load only. The analysis results according to the ASME NB-3200 are shown in Table 6. From the above design evaluations according to the ASME NB-3200, the main piping systems under design extended loading conditions maintain the structural integrity in terms of load-controlled stress limits.

Fig. 20. Distribution of secondary stress in piping system 2 (unit : Pa).

4. Code comparison of the design codes 4.1 Design basis condition When comparing DBR (RB-3600 and ASME B31.1) evaluation results with those from DBA (ASME NB-3200) for piping systems 1 and 2 under the design basis conditions of Fig. 4(a), DBR (RB-3600 and ASME B31.1) results have shown that the range of calculated value was higher than those of DBA (ASME NB-3200). The results from ASME NB-3200 have shown that the range of calculated values was the lowest of the three codes, as shown in Table 7. The results from design by analysis (ASME NB-3200) evaluations have shown lower stress intensities than those from the design by rules (RB-3600 and ASME B31.1), which means that the design by rules (RB-3600 and ASME B31.1) are more conservative as expected. This means that the DBA

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Tabel 7. Code comparisons in design evaluations for piping system Nos. 1 and 2. Calculated-allowable ratio Design code

Piping system 1

Piping system 2

Design by rule

Primary stress 1

Primary stress 2

Secondary stress

RCC-MRx RB-3600

24.2%

33.6%

39.1%

ASME B31.1

21.3%

17.7%

39.1%

ASME NB-3200

14.7%

10.6%

37.6%

RCC-MRx RB-3600

26.8%

45.7%

50.7%

ASME B31.1

50.9%

42.4%

69.1%

ASME NB-3200

11.7%

37.3%

40.6%

Design by analysis Design by rule Design by analysis

Tabel 8. Code comparisons for piping systems 1 and 2 under design extended conditions. Design code

Piping system 1

Design by rule

RCC-MRx RB3600

63.3%

ASME B31.1

93.1%

ASME NB-3200

62.5%

RCC-MRx RB3600

68.7%

ASME B31.1

129.5%

ASME NB-3200

66.7%

Design by analysis

Piping system 2

Design by rule

Calculated-allowable ratio

Design by analysis

of ASME NB-3200 is the least conservative of the three design codes. The results of the code comparisons in the design evaluations for piping systems 1 and 2 are shown in Table 7. In addition, Table 7 shows that ASME B31.1 is more conservative than RB-3600 when comparing the two DBR codes. 4.2 Design extended condition When comparing the DBR (RB-3600 and ASME B31.1) evaluation results with those from DBA (ASME NB-3200) for piping systems 1 and 2 under design extended conditions of Fig. 4(b), DBR (RB-3600 and ASME B31.1) results have shown that the range of calculated values was higher than those of DBA (ASME NB-3200). In addition, a comparison between DBR (RB-3600 and ASME B31.1) has shown that ASME B31.1 is higher than RB-3600 as in the case of the results for design basis condition, which means that ASME B31.1 is the most conservative code of the three design codes. The results of the code comparison in the design extended condition for piping systems 1 and 2 are shown in Table 8.

5. Conclusions A large-scale sodium test loop of STELLA-1 (Sodium integral effect test loop for safety simulation and assessment) has been installed and under operation at KAERI; the loop has two main sodium piping systems. Design evaluations for the piping systems in STELLA-1 loop were conducted first according to the DBR (design by rule) codes of ASME B31.1 and French RCC-MRx RB-3600, and then according to the DBA (design by analysis) code of ASME Section III Subsection NB-3200. The conservatism of the three design codes was quantified based on the design evaluation results according to the design codes. When comparing the DBR codes (RB-3600 and ASME B31.1) with the DBA (ASME NB-3200) code for the present piping systems, the design evaluation results from DBR were shown to be more conservative than the DBA code. When comparing the DBR codes of RB-3600 and ASME B31.1, the non-nuclear DBR code of ASME B31.1 was more conservative than the nuclear DBR code of RB-3600, and there is a concern that it may lead to overly conservative results. Design evaluations of the two sodium piping systems for design basis conditions show that the evaluation results of the piping designs were within all allowable design levels of the codes. However, the design evaluations for the design extended condition have shown that the design allowable levels as per the DBR code of ASME B31.1 were exceeded only for piping system 2 under thermal load conditions, which shows that ASME B31.1 is the most conservative code of the three codes for the present piping systems.

Acknowledgment This study was supported by the Korean Ministry of Science, ICT and Future Planning through its National Nuclear Technology Programs (2012M2A8A2025638) and the Inter-national Research & Development Program (2013K1A3A7A03078195).

Nomenclature-----------------------------------------------------------------------C2, C3 Z m(j, j`) E α

n q1

q ma , q mb i MA Sh SL

: Stress factors for the piping element of concern : Modulus of inertia : (j) and (j`) of stress controlled moments : Young’s modulus : Coefficient of thermal expansion : Poisson’s ratio : Temperature characterizing the linear temperature gradient in the thickness of the wall : Mean values of mean temperature gradient in the thickness of the wall : Stress intensification factor : Resultant moment loading in cross section owing to weight and other sustained loads : Basic material allowable stress at maximum temperature : Sum of the longitudinal stresses owing to pressure,


MB

MC

Pm PL Pb Pe Q

weight, and other sustained loads : Resultant moment loading on the cross section owing to occasional loads, such as thrusts from relief / safety valve loads, from pressure and flow transients, and earthquake : Resultant moment loading range on the cross section owing to the reference displacement load range. For flexibility analyses, the resultant moment owing to the ambient to normal operating load range : General primary membrane stress : Local membrane stress : Primary bending stress : Stress resulting from the constraint of free and displacement : Self-equilibrating stress necessary to satisfy continuity of structure

References [1] H. Y. Lee, J. B. Kim and J. J. Lee, Construction of a high temperature Gr.91 sodium component test, Materials Science Forum, 416-419 (2010) 528-531. [2] Y. I. Kim, Y. B. Lee, C. B. Lee and D. H. Hahn, Sodium cooled fast reactor development in Korea, International Conference on Fast Reactors and Related Fuel Cycles (FR13), 4-7 March, Paris (2013). [3] RCC-MRx, Section III subsection B, design and construction rule For FBR, AFCEN (2012). [4] An American National Standard ASME Code for Pressure Piping, B31.1 (2007). [5] ASME boiler and pressure vessel code, Section III, Div. 1, Subsection NB, Class 1 Components in Elevated Tempera-

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ture Service (2010). [6] H. Y. Lee, J. B. Kim and J. J. Lee, High temperature design and damage evaluation of Mod.9Cr-1Mo steel heat exchanger, J. of Pressure Vessel Technology, Transactions of ASME, 133 (2012) 051101-10. [7] H. Y. Lee, J. H . Eoh and Y. B. Lee, High temperature design and damage evaluation of a helical type sodium-to-air heat exchanger in a sodium-cooled fast reactor, JMST, 27 (9) (2013) 2729-2735. [8] H. Y. Lee, J. B. Kim and H. Y. Park, Creep-fatigue damage evaluation of sodium to air heat exchanger in sodium test loop facility, Nuclear engineering and Design, 250 (2012) 308-315. [9] H. Y. Lee, J. H. Eoh and Y. B. Lee, High-temperature design of sodium-to-air heat exchanger in sodium test loop, Trans. Korean Soc. Mech. Eng. A, 37 (5) (2013) 665-671. [10] ASME boiler and pressure vessel code, Section III, Rules for Construction of Nuclear Power Plant Components, Div. 1, Subsection NH, Class 1 Components in Elevated Temperature Service, ASME (2013). [11] ANSYS User manual, Version 14.0, USA (2011).

Dong-won Lee received his M.S. degree at Chungnam National University at Dept. of computational mechanics in 2012. He is a researcher at Korea Atomic Energy Research Institute. His specialty is design and evaluation of high temperature components, and blast analysis of pressure vessel.