IEC IEEE 63113:2021 pdf free download – Nuclear facilities – Instrumentation important to safety – Spent fuel poolinstrumentation
ln this document the term “spent fuel pool monitoring instrumentation” refers to any monitoringinstrumentation that is specifically intended to detect one or more of the conditions listed above.
Annex A provides further discussion of conditions a) through i) above and the spent fuel poolmonitoring instrumentation functions intended to detect these conditions. lt also gives a diagramshowing an example of how the measurements might physically relate to each other and thespent fuel pool itself.
The specific values corresponding to the above conditions shall be determined based uponplant-specific design information. Instruments that are intended to detect conditions a), d), e)and f) shall accurately indicate the water level when the water is both below and above itssaturation temperature.
Instruments that are intended to detect conditions a), b), and c) are meant for use in plantoperational states.
Instruments that are intended to detect conditions a), d),e), f), and g) are meant for use duringaccident conditions to alert operators to situations that may jeopardize the cooling of spent fuelunder DEC.
Instruments that are intended to detect conditions g), h), and i) are meant for use during severeaccident conditions to alert the operators to situations that may immediately result in or havealready resulted in fuel damage.
A spent fuel pool that contains two or more sections that are connected by normally open gatesmay be treated as a single spent fuel pool. If the isolable sections of the pool are not used forlong-term storage of significant quantities of fuel (as defined by local regulations), sensors forlevel and temperature monitoring channels shall be located in the main pool.Administrativeprovisions shall be put into place to ensure that these instruments are operable before poolsare isolated from each other.
lf, however, the multiple pool sections are normally isolated and used for long-term storage ofsignificant fuel quantities, each section shall be treated as an individual spent fuel pool.
Criteria for spent fuel pool monitoring instrumentation apply to all instruments that are intendedto detect conditions a) through i). Additional criteria are given for DEC spent fuel pool monitoringinstrumentation, and these apply only to instruments that are intended to detect conditions a)and d) through i).
The terms used for the different functions and functional groups intended to detect theconditions identified above and their relationship to plant states are shown in Table 1.
6.1 Range
Spent fuel pool level monitoring instrumentation shall cover the full range of levels for the poolfrom condition b) to condition f) in Clause 5.
lf DEC spent fuel pool monitoring instrumentation is provided for conditions h) and i), the rangeshall be extended to cover the full range of level to condition i).
Spent fuel pool temperature monitoring instrumentation shall cover，with margin，thetemperature range from the minimum expected pool temperature up to the spent fuel poolboiling point (e.g.,10 °C to 125 °C), when pool building pressure is at the structure’s maximumdesign pressure.The temperature measurement locations shall include two points.One pointshall be at the minimum active cooling water level (condition d) and another point shall bebetween the minimum shielding water level (condition e) and the top of the fuel water level(condition f) to provide information for an extended period of time before a significant loss ofinventory causes all of the temperature sensors to become uncovered.
Spent fuel pool radiation monitoring instrumentation (condition g) shall cover the range frombackground levels to 110 % of the calculated maximum dose rate above the pool given themaximum radiological release condition from the pool.
Each spent fuel pool monitoring parameter may be provided by a single instrument,multipleinstruments，or multiple technologies. If multiple monitoring channels or technologies areprovided to cover the full measurement range,overlap between ranges shall be provided toenable the operator to follow trends throughout the entire range and check consistency ofindication in the overlap range.