Document: NUREG-0800
Document ID: ddaa3c7d-ce79-4a3f-aaae-4e4436ab7bc1
Document Type: srp
Title: NUCLEAR DESIGN
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0707/ML070740003.pdf
Revision Date: 2023-06
Chapter: 4
Section ID: 4.3
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Content:
ion that no single malfunction of the RCS can causes the fuel design limits to be exceeded. Meeting the requirements of GDC 25 significantly reduces the possibility that a malfunction in the RCS would result in nuclear fuel damage. 7. GDC 26 requires that two independent RCSs of different design be provided. Review of the nuclear design verifies that two independent RCSs exist, and that one system can reliably control core reactivity during normal power changes and anticipated operational occurrences. The review also verifies that one system can hold the core subcritical under cold conditions. Compliance with GDC 26 provides assurance that core reactivity can be safely controlled and that sufficient negative reactivity exists to maintain the core subcritical under cold conditions, thus minimizing the likelihood of fuel damage and the subsequent release of fission products. 8. GDC 27 requires that the RCSs have a combined capability, in conjunction with poison addition by the emergency core cooling system, of reliably controlling reactivity changes under postulated accident conditions, with appropriate margin for stuck rods. The nuclear design review verifies that the RCSs provide a movable control rod system and a liquid poison system and that the core has sufficient shutdown margin assuming a stuck rod. Meeting the requirements of GDC 27 provides assurance that the RCS will be designed such that damage to the fuel in the event of an accident will be minimized. 4.3-12 Revision 3 - March 2007 9. GDC 28 requires that the effects of postulated reactivity insertion accidents not result in damage to the reactor coolant pressure boundary nor cause sufficient damage to impair the capability to cool the core. This SRP section reviews the reactivity coefficients and rod worths assumed in the analysis of reactivity insertion events in Chapter 15 of the SRP. Compliance with GDC 28 provides assurance that the second barrier (i.e., the reactor coolant pressure boundary) that