Final answer:
The upper part of the steam and water drum is called the steam dome, which helps in separating steam from water to provide dry steam for turbines or other equipment.
Step-by-step explanation:
The upper part of the steam and water drum in boiler systems is known as the steam dome. It is designed to collect the steam generated in the boiler and provide an area where the steam can separate from the water before it exits the boiler and goes into the steam piping system. The steam dome helps to ensure only dry steam is delivered to the turbines or other equipment utilizing the steam, which is essential for efficient operations and preventing damage.