here - Atomic Energy Regulatory Board

project sites by a notification until a detailed report on
measures taken to improve safety of work practices while
working at height was submitted to AERB. Special regulatory
inspections were carried out at all the nuclear projects to
verify the improvement in the industrial safety status after
which the restriction was lifted.
2.2 NUCLEAR POWER PLANTS AND
RESEARCH REACTORS
The Operating Plants Safety Division of AERB
carries out the safety review and monitoring of operating
NPP and research reactors. The Safety Review Committee
for Operating Plants (SARCOP), the apex committee for
overseeing safety of operating plants, held 18 meetings during
the calendar year 2005.
The Unit safety committees established under
SARCOP have met a number of times to review safety related
issues. The information on number of meetings conducted
by various Unit safety committees during 2005 is given in
Table 2.3.
18
Table 2.3: Meetings of Safety Committees
Name of the safety committee No. of
meetings
SARCOP 18
TAPS Safety Committee 6
RAPS - MAPS Safety Committee 12
NAPS - KAPS Safety Committee 7
KGS - RAPS - 3 & 4 Safety Committee 8
IGCAR Safety Committee 3
CESCOP 3
All the NPPs and research reactors operated safely.
Safety status of individual NPPs and research reactors is
briefly described below:
2.2.1 TAPS-1&2
TAPS-1&2 were operational upto a power level
of 160 MWe. The Units remained shutdown between October
1, 2005 and February 14, 2006 for implementation of safety
upgradation and ageing management related inspections for
which simultaneous shutdown of both Units was necessary.
Other safety upgradation jobs had been completed during
operation of the Units and during their normal refueling
outages.
Upgradation of TAPS-1&2:
TAPS-1&2, the boiling water reactor based NPPs,
were commissioned in the year 1969. As stipulated by AERB,
a comprehensive safety review for continued operation of
the Units was completed in the year 2003. The details of
the review were given in the AERB annual report for the
year 2003-2004. Based on these reviews, a number of safety
upgradations were identified towards meeting the current
safety requirements. Important among these are (a)
modification in the emergency power supply system for the
station inclusive of new diesel generators of higher capacity
and Unit-wise segregation of power supplies (b) segregation
of shared systems such as shutdown cooling system and
fuel pool cooling system, (c) addition of an independent set
of Control Rod Drive (CRD) pumps to strengthen the
emergency feed water supply to the reactor, (d) addition of
a supplementary control room and (e) upgradation of fire
protection system. The review also identified the components/
equipment requiring inspection for assessment of health from
ageing considerations. Both Units of TAPS were shutdown
on October 1, 2005, for carrying out the identified
upgradation jobs.
After extensive review of all aspects relating to safety
upgradations, health assessment of equipments, compliance
with all the regulatory requirements/stipulations and
satisfactory progress made towards resolution of the identified
issues, AERB permitted restart of TAPS-1&2 and renewed
the authorisation for operation of Units upto March 2011,
when Application for Renewal of Authorisation (ARA) and
Periodic Safety Review (PSR) of the Units will become due
for submission.
Seismic Re-evaluation of TAPS-1&2
TAPS-1&2 Units were designed for seismic loading
using equivalent static analysis method, which was the state
of the art at the time of their design in mid 1960’s.
Considering the developments in seismic analysis and design,
a need was felt for seismic re-evaluation of TAPS-1&2. The
review basis ground motion parameters for re-evaluation were
considered same as that of the design basis parameters for
the new TAPP-3&4 Units, located nearby. IAEA safety series
28, “Seismic Evaluation of Existing Nuclear Power Plants”
was used by AERB as the review basis. AERB also conducted