One possibility is the EDGAR database in the Securities & Exchange Commission website. Its Advanced search gets 139 hits for the search: westinghouse AND nuclear (you have to put Boolean operators in all caps). The search: "china valves" AND nuclear, limiting to dates 09/01/2008 to 12/30/2008, gets 6 hits. Once you open one of these (frequently long) filings, you can use CTRL-F to find where "nuclear" is on the page. You would also want to try other words, such as fission, uranium, maybe even "pressure vessels", etc. But Edgar is a fairly crude search, and its "automatic" word stemming gets very unsatisfactory results if you try to search "containment", for example. The search: 3m AND "nuclear weapons" gets nothing related, in the past 4 years.
If you are near a large academic library, such as University of Maryland, or even some not so large community college ones, it would be wise to search Ebsco's Business Source, and newspaper full text databases such as Lexis Academic which offer "proximity search". At University of Maryland College Park, we subscribe to Business Source Complete, which gets 7 hits for: Exxon and "nuclear power". But even though the Ebsco default is title, subject words and abstracts only, these 7 hits find nuclear power apparently not related to Exxon. If you "select a field" TX-All Text, the search: exxon w5 "nuclear power" (Exxon within 5 words of the phrase "nuclear power") gets 4 hits, and CTRL-F in the HTML full text quickly finds the terms under separate companies, though very close together in a list.
