Times Crossword 25,344 - an explosive event

Solving Time: 26 minutes, about average for my blog efforts. I suspect this may be on the harder side rather than the easier. It calls for some general knowledge (quite right too), a wee bit of science, bless it, and there are one or two tricky bits of cluing (translation: there are still some clues I haven't worked out) - overall, a good crossword with nothing too controversial.

cd = cryptic definition, dd = double definition, rev = reversed, anagrams are *(--).

ODO means the Oxford Dictionaries Online

Across
1	easy-going - (Captain) Marryat's character = EASY + failing to stay = GOING. A familiar book to most people my age, I guess
6	shtum - Henrys' returned = HS + bread basket = TUM. The H being a reference to the SI unit of magnetic inductance, I guess
9	crouton - heavy defeat = ROUT in racket = CON
10	zooming - ZOO + MING. I was all set to complain that Ming was a dynasty not an emperor, but Wiki says there have been seven Emperor Mings. Eight, if you include this one
11	let-up - don't stop = allow = LET + climbing = UP. So presumably fell is the def., not sure if I have that right?
12	I Claudius - constant = C + praise = LAUD, in "couple in Latin" = II + US. A very neat clue indeed, top class. I Claudius being a very high-class novel by Robert Graves, plus film, play, TV, radio, you name it
13	part song - certain subjects = ARTS in PONG, the def being lay
14	Brno - PUB CHEER CHARLTON + BOO. The second largest city in the Czech Republic, sadly known to me only as the home of the well-known firearms manufacturer CZ
17	romp - PROM, with the P moved from front to back. Dance = romp seems a teensy bit of a stretch to me
18	white tie - with = W + buffet = HIT + film = ET + that is = IE. White tie being what one wears when black tie is just not dressy enough..
21	upholster - UP HOLST + ER
22	miles - Miles being a boy's name, and far away.. seemed a bit weak to me, this one
24	Teheran - well, what = EH, time = ERA with a T at the front and N = noon at the rear.. I always used to know it as Tehran, when did the extra E get added?
25	ooziest - island - I in ducks = OO + relish = ZEST
26	yappy - programme = APP in axes = YY. I spent far too long trying to fit XY in somewhere
27	Damascene - ASCENT in DAME. Not the place for your next holiday, I fear
Down
1	excel - EX CELL, better as in outdo
2	shoot from the hip - CRASS + HOOT FROM THE HIP, a word used in my youth to describe trendy folk
3	gatepost - wicket = GATE + stick = POST. As in "Between you, me and the..."
4	inn signs - "in sines," a homophone. That’s sines as in cosines
5	guzzle - UPSETTING + PUZZLE. The rather crude def. is accurate enough
6	Shogun - appropriate = HOG in paper = SUN. This use of appropriate took a while to dawn on me
7	trinitrotoluene - TRINITY college + *(TO ENROL + EU). I smiled when I saw this word, more familiar to many perhaps as TNT. Another neat clue, if only the surface was a mite more convincing
8	megastore - *(GASOMETER), an instant solve for me as I've seen it somewhere before and quite recently too, Though I'm not sure where. According to Google it was in a Guardian crossword in 2011 and also a Crossword Championship final in 2008. Interesting blog, that!
13	parquetry - QUIET in counter = PARRY. "Late last night I slew my wife, Stretched her on the parquet flooring; I was loath to take her life, But I had to stop her snoring." (Harry Graham)
15	Khartoum - "car tomb"
16	atomizes - cat = TOM in MAIZE'S, the def. being just "fragments," as a verb
19	Blu-Ray - BLURRY, with one R changed to A. Don't ask me about blu-ray, I'm still wondering what to do with all my cassettes
20	stoned - BUSINESS + made firm = TONED. Another one where the penny took time to drop
23	Satie - MADE IT A SYMPHONY, rev. Sadly I know as much about Eric Satie as I do about 19dn.