Resolution of Generic Safety Issues: Issue 20: Effects of Electromagnetic Pulse on Nuclear Power Plants (Rev. 1) ( NUREG-0933, Main Report with Supplements 1–35 )

DESCRIPTION

Historical Background

This concern was raised¹⁸³ because of the potential for a high-altitude nuclear weapon detonation causing a large electromagnetic pulse (EMP) which subsequently could induce large currents and voltages in electrical systems. The concern was that sensitive electronics at nuclear power plants could be irreparably damaged. In addition, Petitions for Rulemaking on EMP (PRM-50-32, 32A, and 32B) have been filed.

Safety Significance

This issue is unique because of its ability to affect more than one plant at the same time. Portions of a nuclear power plant's electrical, instrumentation and control systems may be disabled due to the large currents and voltages which could be induced. Loss of critical systems such as offsite power, emergency onsite power, etc., could lead to loss of core cooling with subsequent core melt.

The original concern was that sensitive electronics would be irreparably damaged, but it now appears that, if failure occurred, it would likely be only momentary (i.e., trip breakers, etc.) and the failed equipment could be restored to service to continue core heat removal.¹¹⁵

Possible Solution

If the electrical equipment necessary for safe shutdown displayed sensitivity to EMP, then a minimum safety margin for the ratio of the peak EMP voltage to its damage threshold voltage could be chosen and the equipment would then be required to meet this criterion. This could then provide assurance that the equipment would not be damaged.

CONCLUSION

Detailed programmatic information on this issue was presented in SECY-81-641⁶⁰⁴ and subsequent program status reports were provided in SECY-82-157⁶⁰⁵ and SECY-82-157A.²⁰³ A study on the effects of EMP on nuclear power plants was documented in NUREG/CR-3069¹¹⁵ and forwarded to the Commission in SECY-83-367.⁶⁰⁶ This issue was RESOLVED with the Commission approval⁶⁰⁷ of the staff's report and no new requirements were established. Continuing staff work in response to the PRMs is a separate entity and does not affect this conclusion.

REFERENCES

0115. NUREG/CR-3069, "Interaction of Electromagnetic Pulse with Commercial Nuclear Power Plant Systems," U.S. Nuclear Regulatory Commission, February 1983. 0183. NUREG-0153, "Staff Discussion of 12 Additional Technical Issues Raised by Responses to the November 3, 1976 Memorandum from Director, NRR to NRR Staff," U.S. Nuclear Regulatory Commission, December 1976. 0203. SECY-82-157A, "Status Report on the NRR Investigation of the Effects of Electromagnetic Pulse (EMP) on Nuclear Power Plants," U.S. Nuclear Regulatory Commission, July 16, 1982. [8205050108] 0604. SECY-81-641, "Electromagnetic Pulse (EMP)—Effects on Nuclear Power Plants," U.S. Nuclear Regulatory Commission, November 5, 1981. [8202090418, 8111250553] 0605. SECY-82-157, "Status Report on the Evaluation of the Effects of Electromagnetic Pulse (EMP) on Nuclear Power Plants," U.S. Nuclear Regulatory Commission, April 13, 1982. [8205050108] 0606. SECY-83-367, "Staff Study of Electromagnetic Pulse (EMP) Effects on Nuclear Power Plants and Discussion of Related Petitions for Rulemaking (PRM-50-32, 32A, and 32B)," U.S. Nuclear Regulatory Commission, September 6, 1983. [8312210152] 0607. Memorandum for W. Dircks from S. Chilk, "SECY-83-367—Staff Study of Electromagnetic Pulse (EMP) Effects on Nuclear Power Plants and Discussion of Related Petition for Rulemaking (PRM-50-32, 32A, and 32B)," November 15, 1983. [8402270019]