How am I supposed to put "铁饭碗" in simple words, and not a paragraph worth of explanation? I can't seem to find suitable adjectives or nouns to concisely interpret the implication of "铁饭碗" (Suppose to refer to jobs that "won't get laid off")。
I think translating 铁饭碗 as "guaranteed lifetime employment" gets the point across quite well. There's also a phrase, "cradle-to-grave socialism" -- it's a little more political than guaranteed lifetime employment, but it accurately reflects the use of the word in Chinese history.
Neither phrase has the English resonance of the Chinese original, but I think both are acceptable choices if you are seeking a short explanation.
Your best bet is to use the translation "Iron Rice Bowl". There is no direct English equivalent, and (according to Wikipedia) there is a precedent for using the phrase in English.
Plus it's always great to expand English :)
Guarantees in terms of job-security, or residency are usually referred to as tenure so I'm going to suggest "Life tenure". Source