E-ISSN 2705-3954 | ISSN 0794-4756
 

Original Research 


PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS

Nuruddeen ABUBAKAR, Isah GARBA, Muhammed Tajuddeen JIMOH, Yakubu Viva IBRAHIM, Dalhatu Balarabe YAHAYA.

Abstract
Thermal hydraulic and safety performance of the Nigeria Research Reactor-1 (NIRR-1) have been analysed to predict the Onset of Nucleate Boiling (ONB), Departure from Nucleate Boiling (DNB), Onset of Flow Instability (OFI) and corresponding parameters using PLTEMP/ANL code coupled with MS excel. This is necessary to establish the thermalhydraulic safety limits and margins for safe operation after changing the reactor’s nuclear fuel recently. Experimental results from the steady state thermal parameters at different operating power levels compared with simulation outcomes from the code agree closely. NIRR-1 demonstrates high inherent safety features under the steady state operating power condition and prevailing natural convection. Steady operation at reactor self-restraint exhibits high negative moderator/coolant temperature feedback which limits power excursion and prevents escalation of temperature and flow in the reactor core. The analysis shows it is possible to raise the reactor power from 34 to 50 kW for enhanced utilisation with considerably sufficient safety margins at minimum ratios of ONB = 1.65, DNB = 8.2 and OFI = 2.5 corresponding to Clad Wall Temperature (T_w) = 75 oC, Core Average or Bulk Coolant Temperature (T_b) = 55 oC, Saturation Temperature (T_sat) = 68 oC, Core Inlet Coolant Temperature (T_1) = 48 oC, Core Outlet Coolant Temperature (T_2) = 62 oC and Coolant Flow Velocity in the Core (U_b) = 0.015 m/s.

Key words: NIRR-1; Thermal hydraulics; Safety margin; Steady state; Operating power


 
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How to Cite this Article
Pubmed Style

ABUBAKAR N, GARBA I, JIMOH MT, IBRAHIM YV, YAHAYA DB, . PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS. NJE. 2020; 27(3): 35-40.


Web Style

ABUBAKAR N, GARBA I, JIMOH MT, IBRAHIM YV, YAHAYA DB, . PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS. http://www.njeabu.com.ng/?mno=71103 [Access: December 26, 2020].


AMA (American Medical Association) Style

ABUBAKAR N, GARBA I, JIMOH MT, IBRAHIM YV, YAHAYA DB, . PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS. NJE. 2020; 27(3): 35-40.



Vancouver/ICMJE Style

ABUBAKAR N, GARBA I, JIMOH MT, IBRAHIM YV, YAHAYA DB, . PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS. NJE. (2020), [cited December 26, 2020]; 27(3): 35-40.



Harvard Style

ABUBAKAR, N. . ., GARBA, I. . ., JIMOH, M. T., IBRAHIM, Y. . V., YAHAYA, D. B. & (2020) PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS. NJE, 27 (3), 35-40.



Turabian Style

ABUBAKAR, Nuruddeen , Isah GARBA, Muhammed Tajuddeen JIMOH, Yakubu Viva IBRAHIM, Dalhatu Balarabe YAHAYA, and . 2020. PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS. Nigerian Journal of Engineering, 27 (3), 35-40.



Chicago Style

ABUBAKAR, Nuruddeen , Isah GARBA, Muhammed Tajuddeen JIMOH, Yakubu Viva IBRAHIM, Dalhatu Balarabe YAHAYA, and . "PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS." Nigerian Journal of Engineering 27 (2020), 35-40.



MLA (The Modern Language Association) Style

ABUBAKAR, Nuruddeen , Isah GARBA, Muhammed Tajuddeen JIMOH, Yakubu Viva IBRAHIM, Dalhatu Balarabe YAHAYA, and . "PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS." Nigerian Journal of Engineering 27.3 (2020), 35-40. Print.



APA (American Psychological Association) Style

ABUBAKAR, N. . ., GARBA, I. . ., JIMOH, M. T., IBRAHIM, Y. . V., YAHAYA, D. B. & (2020) PREDICTIONS OF ONSET OF NUCLEATE BOILING, DEPARTURE FROM NUCLEATE BOILING AND ONSET OF FLOW INSTABILITY FOR NIRR-1 AT STEADY STATE OPERATING POWER CONDITIONS. Nigerian Journal of Engineering, 27 (3), 35-40.