Document: NUREG-0800
Document ID: e1169529-d2cb-4947-9efe-b23d927f4aa9
Document Type: srp
Title: NUREG40800
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052350520.pdf
Revision Date: 2023-06
Chapter: 8
Section ID: 8
CFR Part: 
CFR Title: 

Content:
that the potential for common failure modes should preclude interconnection of onsite and offsite power sources except for short periods for the purpose of load testing. Review of the use of emergency diesel-generator sets for peaking service leads to the conclusion that the required frequent interconnection of the preferred and standby power supplies increases the probability of their common failure. B. BRANCH TECHNICAL POSITION General Design Criterion 17 and IEEE Std 308 should be interpreted as prohibit- ing the use of plant emergency power diesel-generator sets for purposes other than that of supplying standby power when needed. In particular, emergency power diesel-generator sets should not be used for peaking service. C. REFERENCES IEEE STO 308, "Criteria for Class lE Systems for Nuclear Power Generating Stations." SRA-6 Rev. 2 - July 1981 BRANCH TECHNICAL POSITION ICSB-ll (PSB) STABILITY OF OFFSITE POWER SYSTEMS A. BACKGROUND The staff has traditionally required each applicant to perform stability studies for the electrical transmission grid which would be used to provide the offsite power sources to the plant. The basic requirement is that loss of the largest operating unit on the grid will not result in loss of grid stability and availability of offsite power to the plant under consideration. In some cases, such as plants on the island of Puerto Rico, the plant is connected to an isolated power system of limited generating capacity. These kinds of isolated power systems are inherently less stable than equivalent systems with supporting grid interties. It is also obvious that limited systems are more vulnerable to natural disasters such as tornadoes or hurricanes. B. BRANCH TECHNICAL POSITION 1. The staff has concluded, from a review of appropriate reliability data, that power systems with supporting grid interties meet the grid availabil- ity criterion with some margin. This conclusion is applicable to the review of most plants located on the U.S.