Steam Systems

Question 1

Which main steam rad monitors are used to monitor SG tube leakage following a reactor trip?

Answer 1

Steam line high range radiation monitors - High Range GM tubes are located on each Main Steam line at each penetration next to the Reactor Building wall. ODCM required.

Question 2

What is required for TS associated with the MSSVs? What actions are taken if one or more inoperable?

Answer 2

ANO Technical Specifications section 3.7.1 requires seven MSSV’s operable per steam line in Mode’s 1, 2 & 3. Reduce power within capacity within 4 hours. Approximately 13 – 15% reduction per MSSV.

Question 3

What indications are available to notify operators of MSSV open?

Answer 3

K07-C5 MSSV open alarm and MSSV open indication on ATOG screen of SPDS

Question 4

What are the setpoints for MSSVs?

Answer 4

(1050 – 1100 psig)

Question 5

What is setpoint for the ADV and what is its capacity? When does ADV block valve open?

Answer 5

1020 psig / 5% power capacity / Block opens at 21” vacuum / Power sources are B51/61

Question 6

What are the TS requirements for the MSIVs?

Answer 6

Both MSIVs are required per TS 3.7.2 in modes 1, 2 and 3.

Question 7

What provides a backup source of air for the MSIVs and ADVs if loss of IA occurs

Answer 7

Dedicated air accumulators provide adequate air to hold MSIV open for 30 min during a loss of IA given the ADV is not being operated.

Question 8

What is the design requirement time that MSIVs are set to close?

Answer 8

Hydraulic system control speed of valve closure and is set to close in 3 +/- 0.3 seconds.

Question 9

Where are the N16 detectors, what are the used to and are they required per licensing documents?

Answer 9

Downstream of the MSIVs, used for SG tube leakage while at power and are not required per TS, TRM or ODCM.

Question 10

When do the TBVs automatically close and when can they be reset?

Answer 10

Close at 21” and can be reset at 23” (HS in control room can override interlock).