By Steve Keating

TORONTO (Reuters) - The National Hockey League completed two days of experiments in a not-so-secret Toronto laboratory Thursday that would have hockey purists squirming in horror as it tinkered with ways to upgrade the game.

For those who believe hockey is fine in its current form, there is little to fear with few, if any, of the nearly 30 tweaks to rules likely to be adopted.

But while the NHL believes it already has a high-caliber product it continues to search for new ways to squeeze more horsepower out of the game.

"That's what this is for, it's to see what works and what doesn't work," Brendan Shanahan, the NHL's vice-president of player safety and hockey operations, told reporters.

"It's to take some of the conversations that go on in boardrooms to the ice and see it firsthand instead of wondering how it is going to look."

"This is information. It is what a lot of companies and corporations do. It's research and development."

Using the top prospects for the 2012 NHL Entry Draft as guinea pigs, the league put teams through scrimmages and tested out a wide array of new rules while introducing technology and player safety upgrades.

The rules that govern the game will remain the same when the 2011-12 season opens in October, but fans may notice a few cosmetic changes around the rink.

One change will see curved glass at the end of team benches to prevent a repeat of the concussion and vertebra injury that Montreal's Max Pacioretty suffered when he was slammed into the unprotected turnbuckle by Boston's Zdeno Chara.

There could also be a new verification line painted just behind the goal crease to help off-ice officials determine if a goal has been scored during a video review while nets could be made shallower so players have move room.

"Everyone wants to talk about the rules but some of the advances in technology, goal reviews, the verification line, the shallow nets - we've seen them two years now and I think it's time to try them in some exhibition games with real NHL players," said Shanahan.

"We don't want to do anything reactive but at the same time we're seeing some things in this camp that have looked good and we're ready to start testing it out in some exhibition games."

While the Research and Development camp has had the relaxed feel of science field trip things will turn serious quickly with the opening of training camps less than a month away.

With Pittsburgh Penguins captain Sidney Crosby still battling post-concussion symptoms and the NHL still coming to grips with the deaths of two players with links to depression this offseason, the league will be diving into bigger issues.

NHL Commissioner Gary Bettman, who watched the first day of camp, said the league was concerned enough over the deaths of Winnipeg's Rick Rypien and New York Ranger Derek Boogaard that it will likely review its substance abuse and behavioral health program to see if it can be improved.

The tone of the summer camp underlined the NHL is prepared to take hard look at both on- and off-ice issues, whether it be two-on-two overtime or substance abuse.

(Editing by Frank Pingue)