PHWR Safety 2014 / CANSAS-2014 Workshop 2014 June 23-25 Jun Yang AECL PRESSURE DROP TESTS PERFORMED WITH EXTERNALLY AND INTERNALLY COOLED ANNULAR FUEL BUNDLES PHWR Safety 2014 / CANSAS-2014 Workshop 2014 June 23-25 Jun Yang AECL UNRESTRICTED / ILLIMITÉ AECL - OFFICIAL USE ONLY / À USAGE EXCLUSIF - EACL

Project Goal Test Facility Test Results Conclusions Outline UNRESTRICTED / ILLIMITÉ

Project Goal AECL is developing an externally and internally cooled annular fuel (ICAF) bundle, which is considered to have improved thermalhydraulic characteristics as compared to the traditional CANDU type bundles. This experimental program is proposed to investigate the hydraulic behavior of the ICAF bundle in support of the bundle development. The objectives of the single phase pressure drop experiment are to investigate the hydraulic characteristics of the ICAF bundle, obtain pressure drop related information of the ICAF bundle for code verification. The scope of the single phase pressure drop experiment is to obtain pressure distribution information, obtain bundle misalignment junction signature information, obtain flow split information. UNRESTRICTED / ILLIMITÉ

Test Facility – Test Station The single phase pressure drop tests were performed in MR-2 horizontal test station with a string of three ICAF bundles positioned in an uncrept flow tube using deionised water as working fluid at atmospheric pressure and a temperature of 50°C. UNRESTRICTED / ILLIMITÉ

Test Facility – Test Section Flow tube Bundle string Pressure Taps and Valve Banks UNRESTRICTED / ILLIMITÉ

Test Facility – ICAF Bundle The ICAF bundle consists of a two‑ends‑blocked central element , and 24 annular fuel elements arranged in two concentric rings UNRESTRICTED / ILLIMITÉ

Test Results – Pressure Distribution Tests and Results The obtained pressure distribution data for the ICAF bundle cover a mass flow rate range of 7 kg/s to 18 kg/s, and a Reynolds number range of 23852 to 62535. The pressure loss increases with increasing mass flow rate, and the pressure loss coefficient decreases with increasing Reynolds number. UNRESTRICTED / ILLIMITÉ

Test Results – Pressure Distribution Tests and Results The one bundle overall pressure loss (over a whole bundle length of 495.3 mm) was calculated. The one bundle overall pressure loss of the aligned ICAF bundle is smaller than that for the standard bundle by approximately 25%. UNRESTRICTED / ILLIMITÉ

Test Results – Bundle Misalignment Junction Signature Tests and results The angle adjustment mechanism consisted of a worm drive set and a 10 turn potentiometer (or informally a pot). During the experiment, the minimum and the maximum measured angle of the bundle is 3° to 93°. The ICAF bundle aligns for every 45° rotation UNRESTRICTED / ILLIMITÉ

Test Results – Bundle Misalignment Junction Signature Tests and results The shapes of the bundle misalignment junction signatures at different mass flow rates are the same, although the magnitudes of pressure drop are different. The determined most probable misalignment angle (defined as the smallest angle of misalignment between two bundles that provides the average junction pressure drop over 360°) for ICAF bundles is 7°. Focusing only the bundle misalignment angle from 0 to 45°, it was found that the minimum pressure drop occurred at 0 and 45°, and the maximum pressure drop occurred at approximately 14 and 31°. In addition, a local minimum was also observed at 22.5°. UNRESTRICTED / ILLIMITÉ

Test Results – Flow Split Tests and Results Flow split ratio: the ratio of the mass flow rate distributed to the internal flow channel to the total mass flow rate distributed to both external and internal flow channels. Focusing on the middle portion of an ICAF bundle (e.g., between Pressure Taps PT 9 and PT 16), the flow moving through the internal channel is considered to have no interference on the pressure drop over this portion (i.e., P 9 to P 16). This pressure drop is the only function of the mass flow rate distributed to the external flow channel, Comparison of Pressure Drop (P9-P16) Variation with Mass Flow Rate Between Aligned ICAF Bundles and ICAF Bundles with Internal Channel Blocked. UNRESTRICTED / ILLIMITÉ

Test Results – Flow Split Tests and Results Relationship of Mass Flow Rate as a Function of Pressure Drop (P9 P16) for ICAF Bundle with Internal Channel Blocked UNRESTRICTED / ILLIMITÉ

Test Results – Flow Split Tests and Results The flow split ratio is independent of the mass flow rate in single phase water flow in the absence of vapor generation. The determined flow split ratio for the alignment ICAF bundle varies between 24.05% and 24.96%, with an average value of 24.43% and a standard deviation of 0.31% for eight data points. The determined average flow split ratio of 24.43% is close to the internal channel to total channel cross sectional flow area ratio of 24.87%. The flow split ratio changes with the change in misalignment angle. UNRESTRICTED / ILLIMITÉ

Conclusions The one bundle overall pressure loss of the aligned ICAF bundle is smaller than that for the reference/standard bundle by approximately 25%. The determined most probable misalignment angle for ICAF bundles is 7° The determined flow split ratio is 24.43%. UNRESTRICTED / ILLIMITÉ

AECL - OFFICIAL USE ONLY / À USAGE EXCLUSIF - EACL