Comprehensive Prediction of Thermosyphon Characteristics in Reactor Passive Cooling System Simulation Loop FASSIP-01

• Main Author: H. Tjahjono
• Format: Article
• Language: English
• Published: Center for Development of Nuclear Informatics, National Nuclear Energy Agency (BATAN) 2017-12-01
• Series: Atom Indonesia
• Subjects: Thermosyphon; Passive system; Nuclear reactor; FASSIP-01 model; MATLAB
• Online Access: http://aij.batan.go.id/index.php/aij/article/view/777

<p class="MsoNormal" style="margin-top: 0cm; margin-right: -5.1pt; margin-bottom: .0001pt; margin-left: -5.3pt; text-align: justify; tab-stops: 1.0cm;"><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">Passive cooling mechanism for a nuclear reactor has </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">been </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">proven to be very important since the Fukushima Daiichi Reactor accident </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">that </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">was caused by active cooling system malfunction due to total loss of electrical power source. In the Center for Nuclear Reactor Technology and Safety of BATAN, the cooling mechanism </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">was</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;"> studied by using a natural circulation test loop named FASSIP-01 that applie</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">d</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;"> thermosyphon mechanism</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN"> of water inside pipe</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">s</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN"> of 1” diameter</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">. This study aimed to </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">analytica</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">l</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">ly predict</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">the thermal characteristics of the loop </span></span><span class="longtext"><span style="font-size: 9pt;" lang="IN">including its response time to</span></span><span class="longtext"><span style="font-size: 9pt;">wards</span></span><span class="longtext"><span style="font-size: 9pt;"> <span lang="IN">steady condition </span></span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">using</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">the MATLAB calculation program. This prediction derived the influence of several parameters such as the heat transfer coefficient of the cool</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">er</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;"> side</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;"> <span lang="IN">(h-cooler)</span></span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">, the heater power, the elevation difference between the h</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">eater</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;"> and co</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">o</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">l</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">er</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">(</span></span><span class="longtext"><span style="font-size: 9.0pt; font-family: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; color: #222222; mso-ansi-language: IN; mso-char-type: symbol; mso-symbol-font-family: Symbol;" lang="IN">D</span></span><span class="longtext"><em><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">Z</span></em></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">)</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">, and the effects of the insulation thickness of pipe </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">(IT) on</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;"> the flowrate, temperature, and the heat power distribution across all components in the loop. </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">The result show</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">ed</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN"> that by</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">avoiding boiling condition</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">, </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">for transferring the heater power of 1</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">000 </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">W and 2000 W,</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">the</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;"> needed </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">h-cooler </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">exceeds </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">200 and 400 W m</span></span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222;">-</span>}</span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">2</span>}</span><span class="longtext"><span style="font-size: 9.0pt; font-family: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; color: #222222; mso-ansi-language: IN; mso-char-type: symbol; mso-symbol-font-family: Symbol;" lang="IN">°</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">C</span></span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222;">-1</span>}</span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">,</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN"> respectively. For </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">a </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">h-cooler of</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;"> </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">200 W m</span></span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222;">-</span>}</span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">2</span>}</span><span class="longtext"><span style="font-size: 9.0pt; font-family: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; color: #222222; mso-ansi-language: IN; mso-char-type: symbol; mso-symbol-font-family: Symbol;" lang="IN">°</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">C</span></span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222;">-1</span>}</span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">, t</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">he circulation flow rate </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">increase</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">d </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">from 0.04 to 0.06 kg/s</span></span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222;">-1</span>}</span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;"> for </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">heater power</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;"> increase</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN"> from 1000 W to 2000 W. Those flow rates </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">were d</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">ecrease</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">d</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN"> to 0.037 and 0.052 kg</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">s</span></span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222;">-1</span>}</span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN"> by increasing h-cooler to 1000 W m</span></span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222;">-</span>}</span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">2</span>}</span><span class="longtext"><span style="font-size: 9.0pt; font-family: Symbol; mso-ascii-font-family: 'Times New Roman'; mso-hansi-font-family: 'Times New Roman'; color: #222222; mso-ansi-language: IN; mso-char-type: symbol; mso-symbol-font-family: Symbol;" lang="IN">°</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">C</span></span><span class="longtext">^{<span style="font-size: 9.0pt; color: #222222;">-1</span>}</span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">.</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">T</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">he results </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">we</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">re in agreement </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">with</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN"> other </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">studies on </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">rectangular loops in the literature.</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">T</span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">he time needed to reach 95 % towards steady state was </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222; mso-ansi-language: IN;" lang="IN">predicted </span></span><span class="longtext"><span style="font-size: 9.0pt; color: #222222;">to be more than 13 hours. </span></span><span style="font-size: 9.0pt; mso-bidi-font-weight: bold;">Reduction </span><span style="font-size: 9.0pt; mso-ansi-language: IN; mso-bidi-font-weight: bold;" lang="IN">of this</span><span style="font-size: 9.0pt; mso-bidi-font-weight: bold;"> time to less than five hours was possible by reducing the heater tank volume from 100 L to 30 L or by modifying the starting heater input power.</span></p>