Document: NUREG-0800
Document ID: b085cd1c-2d74-4547-b757-d8513d0cb353
Document Type: srp
Title: OVERPRESSURE PROTECTION
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070419.pdf
Revision Date: 2023-06
Chapter: 5
Section ID: 5.2.2
CFR Part: 
CFR Title: 

Content:
m prevents overpressurization of the reactor coolant pressure boundary under the most severe transients and limits the reactor pressure during normal operational transients. Overpressure protection is provided by ______ safety and relief valves located on the four main steam lines between the reactor vessel and the first isolation valve inside the drywell. The relief and safety valves are distributed among the four main steam lines such that a single accident cannot disable the automatic overpressure protection function. Normally, BWRs are analyzed at 105% rated steam flow at a pressure of 7171 kPag (1040 * psig). Except in those cases in which the applicant proposes an acceptable alternative method for complying with specified portions of the Commission's regulations, the method described herein will be used by the staff in its evaluation of conformance with Commission regulations. 5.2.2-7 DRAFT Rev. 3 - April 1996 The valves discharge through piping to the suppression pool. The valves have setpoints that range from ______ to ______ kPag ( ______ to ______ psig) . 26 Their total capacity at their setpoint is ______ % of rated steam flow. To determine the ability of the overpressure protection system to prevent overpressurization, the applicant has analyzed the most severe overpressure transients. The analysis was performed assuming that: (a) the plant is in operation at design conditions of % of rated steam flow and a reactor vessel 27 * 28 dome pressure of kPag (psig) , and (b) the reactor is shut down by ______. * 29 The calculated peak pressure at the bottom of the vessel is ______ kPag (______ psig) , a value within the code allowable of ______ kPag (______ psig) (110% 30 31 of vessel design pressure). 2. PWRs The overpressure protection system prevents overpressurization of the reactor coolant pressure boundary under the most severe transients and limits the reactor pressure during normal operational transients. Overpressurization protection is provided by