(9) Net periodic pension expense for the U.S. and non-U.S. defined benefit pension plans includes the following components:

	U.S. Pension Plan												Non-U.S. Pension Plans
	Three Months Ended						Nine Months Ended						Three Months Ended						Nine Months Ended
	September 30,						September 30,						September 30,						September 30,
(in thousands)	2013			2012			2013			2012			2013			2012			2013			2012
Service cost	$	1,613		$	1,489		$	4,840		$	4,468		$	3,809		$	1,921		$	11,505		$	5,815
Interest cost	7,275			8,323			21,825			24,970			7,989			8,070			23,925			24,518
Expected return on assets	(7,744		)	(8,830		)	(23,232		)	(26,492		)	(11,527		)	(10,369		)	(34,507		)	(31,446		)
Amortization of prior service cost	26			(28		)	77			(85		)	—			—			—			—
Recognized net actuarial loss	1,510			3,409			4,530			10,226			1,683			786			5,058			2,352
Net periodic pension expense	$	2,680		$	4,363		$	8,040		$	13,087		$	1,954		$	408		$	5,981		$	1,239

The company currently expects to fund approximately $20 million to $40 million into its defined benefit pension plans during 2013, which is expected to be in excess of the minimum funding required. During the nine months ended September 30, 2013, contributions of approximately $11 million were made by the company.

During the third quarter of 2013, the company’s Board of Directors approved an amendment to the U.S. pension plan to freeze the accrual of future service-related benefits for craft participants on December 31, 2013. The amendment did not have a material impact on the plan’s pension obligation or accumulated other comprehensive income.

The preceding information does not include amounts related to benefit plans applicable to employees associated with certain contracts with the U.S. Department of Energy because the company is not responsible for the current or future funded status of these plans.