Definition: In this task, you're given a question, along with a context passage which has extra information available on certain terms mentioned in it. Your job is to determine which sentence(s) from the passage can be used to search for further information needed to answer the question.
Input: Question: How high is the gamma radiation from nuclear fuel? Passage:The nuclear fuel elements were made of refractory ceramic based on beryllium oxide, with enriched uranium dioxide as fuel and small amount of zirconium dioxide for structural stability. The fuel elements were hollow hexagonal tubes about long with distance between the outer parallel planes, with inside diameter of . They were manufactured by high-pressure extruding of the green compact, then sintering almost to its theoretical density. The core consisted of 465,000 individual elements stacked to form 27,000 airflow channels; the design with small unattached elements reduced problems related with thermal stresses. The elements were designed for average operation temperature of ; the autoignition temperature of the reactor base plates was only 150C higher. The neutron flux was calculated to be 910 neutrons/(cms) in the aft and 710 neutrons/(cms) in the nose. The gamma radiation level was fairly high due to the lack of shielding; radiation hardening for the guidance electronics had to be designed.

Output:
The gamma radiation level was fairly high due to the lack of shielding; radiation hardening for the guidance electronics had to be designed