PENSION AND POSTRETIREMENT HEALTH AND LIFE BENEFITS

The components of net benefit costs for pension and postretirement health and life benefit plans were as follows (in millions):



	Defined Benefit Pension Plans												Postretirement Health and Life Benefit Plans
	Three Months Ended September 30,						Nine Months Ended September 30,						Three Months Ended September 30,						Nine Months Ended September 30,
	2013			2012			2013			2012			2013			2012			2013			2012
Service costs	$	1.4		$	3.6		$	8.8		$	10.9		$	0.9		$	0.9		$	2.7		$	2.7
Interest costs	11.5			12.1			33.5			36.2			2.2			2.7			6.7			8.3
Expected returns on plan assets (gains)	(12.8		)	(12.9		)	(38.3		)	(38.9		)	(0.5		)	(0.7		)	(1.7		)	(2.1		)
Amortization of prior service costs	—			0.3			0.7			1.1			—			—			—			—
Amortization of actuarial (gains) losses, net	2.0			5.0			14.2			14.8			0.6			1.2			2.0			3.4
Curtailment (gains)	—			—			(0.7		)	—			—			—			—			—
Net benefit costs	$	2.1		$	8.1		$	18.2		$	24.1		$	3.2		$	4.1		$	9.7		$	12.3

USEC expects to contribute $24.1 million to the defined benefit pension plans in 2013, including $20.9 million of required contributions under ERISA and $2.5 million to non-qualified plans. USEC has contributed $16.2 million in the nine months ended September 30, 2013.

There is no required contribution for the postretirement health and life benefit plans under ERISA and USEC does not expect to contribute in 2013. USEC receives federal subsidy payments for sponsoring prescription drug benefits that are at least actuarially equivalent to Medicare Part D.

Effective August 5, 2013, accrued benefits for active employees who are not covered by a collective bargaining agreement have been frozen under the defined benefit pension plans. The retirement benefit is fixed and will no longer increase based on service or earnings. The freeze of the defined benefit pension plans is part of the internal organizational structure review effort. The defined benefit pension plans were amended to allow a lump sum payment option to active employees who are not covered by a collective bargaining agreement who are terminated as a result of participation in a reduction in force from August 5, 2013 through December 31, 2014. The defined benefit pension plans were further amended to allow a one-time voluntary election for a lump sum payment in December 2013 to certain former employees with deferred vested pension benefits. Any lump sum distributions would fully settle USEC's long-term pension obligations related to those benefits. Settlement charges may be recognized in the fourth quarter of 2013 or 2014 related to the immediate recognition of actuarial losses accumulated in other comprehensive income, a component of stockholders' equity.

A curtailment occurs when an employer eliminates accrual of pension benefits for some or all future services of a significant number of employees covered by the pension plan. When a curtailment occurs, plan assets and benefit obligations are remeasured. The remeasurement date for the curtailment was June 30, 2013. The net effect of the curtailment on the net periodic cost was a gain of $0.7 million and a decrease of $138.3 million on the pension liability (unfunded status) and accumulated other comprehensive income. USEC will continue to review further potential curtailment accounting impacts for those employees severed during 2013 and anticipated to be severed in the immediate future as part of workforce reductions.

The key economic assumptions for the June 30, 2013 remeasurement have changed from the December 31, 2012 measurement. The discount rate used at June 30, 2013 is 4.92% compared to 4.07% used at December 31, 2012, the salary growth rate remained the same at 4.00%, and the expected return on assets also remained the same at 6.75%. The expected contributions to the pension plans for 2013 remain the same.

Prior to the start of 2012, a significant portion of the costs related to pension and postretirement health and life benefit plans were attributed to Portsmouth contract services, based on the employee base performing contract services work. Starting in 2012, ongoing retiree benefit costs related to USEC's former Portsmouth employees are charged to the LEU segment rather than the contract services segment based on our continuing LEU segment operations that support our active and retired employees. These net benefit costs totaled $7.5 million for the nine months ended September 30, 2013 and $9.9 million for the nine months ended September 30, 2012 and are directly charged to cost of sales rather than production.

Net periodic benefit costs related to continued operations are allocated to SWU inventory costs, selling, general and administrative expense, and advanced technology costs.

Other Plans

Effective August 5, 2013, certain employees impacted by the pension freeze discussed above will be eligible to receive an enhanced matching contribution formula under the USEC Savings Program (401(k) plan). USEC's maximum matching contribution for these individuals was increased from 4% to 7% of eligible earnings in August.