Welsome, SillyMe. So sorry about your Mom.
Several times here on this thread radiation's been discussed. I think we had the latest discussion probably about 10 pages back or so, but definitely just this past month.
Radiation is done after surgery to kill any microscopic cancer cells remaining after the tumor is removed, so as to really get rid of all of it not only in the breast but sometimes under the arm (axilla) and up by the clavicle. You go daily to the radiation center, check in, get your radiation and leave, the whole thing taking a half an hour or so. The longest appointment is the one in which they set everything up which is done under CT scan (I was in the scanner lying perfectly still for over an hour). They also place some very tiny permanent marks on your skin in several places as markers for the radiation beams which need to be very precise each time. As a general rule they try to only do radiation once to the area, so those marks will let doctors in the future know that radiation has already been given and also mark the spot. They give the smallest amount of radiation to kill the cells but not do damage to anything else.
Chemotherapy, on the other hand, is meant to kill any cells which may have left the original tumor site and traveled via the lymph and blood system to distant places. Usually this is only given if the cancer is found to be "invasive" - which means they can already see that it's left it's capsule and spread out locally into the tissue. That's what they'll be looking for on pathology - to see if there are any features which would warrant chemo (as well as a host of other things such as size, type, hormone receptor status and such). If a tumor is "non-invasive" then surgery and/or radiation is usually recommended without chemo because the cancer cells have been contained within the capsule of the tumor. (I'd given a link when we discussed it last time - it's a good article on how survival and recurrence rates are better when the surgery and radiation are given together in the case of non-invasive cancer; and surgery, radiation and chemo in the case of invasive cancer).
Here's a link to get you started on reading to help your Mom.
http://www.breastcancer.org/ There are many good books as well but the bible is The Breast Book by Susan Love, MD (I think that's the name, anyway, you'll find it, it's everywhere). Warning - the reading is scary and overwhelming at times. Read what you have to read to become informed but then stop. Learn the basics and then take your questions to your doctor's appointments. You will want to start looking for a good breast surgeon and radiation oncologist at least. Oh yes, and a good support center where she can "let it all hang out" with others who've been through it and have the same emotions associated with it. It is very difficult for all of us "sistas", regardless of the type of breast cancer we have.
I suppose it's kind of good that they're not sure she'll need chemo - maybe they haven't yet spotted an invasive component to the tumor which would be great news. (It's kind of nice to find the good news along with the bad when it comes to this disease.

). By contrast, on my initial biopsy we knew right away it was invasive and that I would need chemo. Hopefully surgery and radiation would be the end of it for her. Good luck reading and you know where to find us if we can be of help or support.

to you and your Mom. Thanks for being so supportive of her.
