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Proceedings of the 24th National and 2nd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2017)


ISBN Онлайн: 978-1-56700-478-6

TRANSIENT ANALYSIS OF INADVERTENT CLOSURE OF BLEED CONDENSER LEVEL CONTROL VALVES OF 700 MWE INDIAN PRESSURIZED HEAVY WATER REACTOR

DOI: 10.1615/IHMTC-2017.2670
pages 1909-1913

S. Phani Krishna
NPCIL, RS&A Directorate Nabhikiya Urja Bhavan, Anushakti Nagar, Mumbai, PIN-400094, India

Santanu Pahari
Nuclear Power Corporation of India Limited NUB, Anushakti Nagar, Mumbai, PIN-400094, India

S. Hajela
Directorate of Reactor Safety & Analysis, Nuclear Power Corporation of India Limited Nabhikiya Urja Bhavan, Anushakti Nagar, Mumbai, Maharashtra, PIN-400094, India

Mukesh Singhal
Nuclear Power Corporation of India Limited NUB, RS&A Directorate Nabhikiya Urja Bhavan, Anushakti Nagar, Mumbai, PIN-400094, India

Аннотация

700 MWe Indian Pressurized Heavy Water Reactor (IPHWR) is a horizontal channel type reactor with two loops of Primary Heat Transport (PHTS) system. Bleed condenser (BCD) is normally used to condense the hot coolant bled through bleed control valve. It also condenses steam released through over pressure relief through Instrumented Relief valves (IRVs) and the steam relieved from pressurizer.
A pair of control valves at downstream of bleed cooler control level in BCD. A third, smaller size control valve is provided in parallel with BCD level control valves for controlled passage of coolant to PHTS purification system, when BCD level control valves are closed for protecting ion exchange columns on bleed cooler outlet temperature high.
In this paper two cases are considered for analysis with postulated initiating event as follows:
Case 1: Two large level control valves closure
Case 2: All three level control valves closure.
Transient analysis was performed using ATMIKA-T in- house developed 3-D neutron kinetics coupled thermal hydraulics computer code. This paper provides timeline of following sequence of events which is important for operator's action to maneuver the event.
• Flow through valves (whichever is closed) becomes zero
• Reactor set back on BCD level high
• Auto start of stand by Primary pressurizing pump (PPP) on PHTS pressure low
• PPP trip on BCD pressure high
• Auto start of Fueling Machine (F/M) supply pump
• Primary coolant pump (PCP) trip
• Reactor trips on PCP trip
• Turbine Trips