Gas turbine engine with integral actuation system

An engine system, comprising:

• a gas turbine engine including a compressor section, a combustor section, a turbine section and a flowpath extending sequentially through the compressor section, the combustor section and the turbine section, the compressor section comprising a compressor rotor, and the turbine section comprising a turbine rotor configured to drive rotation of the compressor rotor;
• an actuation system including a fluid reservoir, a flow regulator and a flow circuit, the flow regulator comprising a barrier between the fluid reservoir and the flow circuit, the flow regulator configured to fluidly decouple the fluid reservoir from the flow circuit when the barrier is intact, the flow regulator configured to fluidly couple the fluid reservoir with the flow circuit when the barrier breaks, and the flow circuit configured to direct gas from the fluid reservoir into the flowpath when the barrier breaks, wherein the barrier is integral with a wall of the fluid reservoir, and the barrier comprises a wall with a stress concentrator;
• and
• an ignitor configured to explode to ignite fuel within the fluid reservoir to provide the gas.