NUREG-1537, Part 2 - NRC

CHAPTERS
Ewauation Findings
This section of the SAR should contain sufficient information to support the
following types of conclusions, which will be included in the staffs safety
evaluation report:
* The design bases, functional descriptions, and procedures for the primary
coolant makeup water system give reasonable assurance that the quantity
and quality of water required will be provided.
* The system design or procedures will prevent overfilling of the primary
coolant system or malfimetion of the makeup water system and will prevent
the loss or release of contaminated primary coolant that would exceed the
requirements of 10 CFR Part 20 and the facility ALARA program
guidelines.
* The system design or procedures will prevent contaminated primary
coolant from entering the potable water system through the makeup water
systemn
* The technical specifications, including testing and surveillance, provide
reasonable assurance of necessary makeup water system operability for
normal reactor operations.
5.6 Nitrogen-16 Control System
Areas of ReWiew
Non-power reactors that use either light or heavy water for neutron moderation or
cooling will produce nitrogen-16 by the fast neutron-proton reaction in oxygen-16.
Nitrogen-16, a high-energy beta and gamma ray emitter with a half-life of
approximately 7 seconds, is a potential source of high radiation exposure at watercooled
non-power reactors. It tends to remain dissolved in the primary coolant
water as it leaves the core. The quantity and concentration of nitrogen-16 should
be considered and pro'visions made to control personnel exposure. Because of the
retively short half-life potential doses can be decreased by delaying the coolant
within shielded regions. For reactors using natural-convection cooling in a large
open pool, stirring or diffusing the convection flow to the surface can produce a
delay.'' For forced-flow cooling, passing the coolant through a large shielded and
baffled tank can produce the delay. In some non-power reactor designs, the entire
primary coolant system may be shielded. Specific areas of review for this section
are discussed in Section 5.6 of the format and content guide.
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