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Withdrawal of Regulatory Guide

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Nuclear Regulatory Commission.


Withdrawal of Regulatory Guide 1.56, “Maintenance of Water Purity in Boiling Water Reactors.”

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Matthew D. Yoder, Division of Component Integrity, Office of Nuclear Reactor Regulation, U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, telephone 301-415-4017 or e-mail

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I. Introduction

The U.S. Nuclear Regulatory Commission (NRC or Commission) is withdrawing Regulatory Guide (RG) 1.56, “Maintenance of Water Purity in Boiling Water Reactors,” Revision 1, dated July 1978. Revision 1 of RG 1.56 was issued for comment in July 1978 and never finalized. It was intended to support General Design Criterion (GDC) 14, “Reactor Coolant Pressure Boundary” and GDC 31, “Fracture Prevention of Reactor Coolant Pressure Boundary” of Appendix A, “General Design Criteria for Nuclear Power Plants,” in Title 10, Part 50, of the Code of Federal Regulations, “Domestic Licensing of Production and Utilization Facilities.”

RG 1.56 describes an acceptable method for maintaining water purity levels in the reactor coolant in order to ensure that degradation of the reactor coolant pressure boundary is not exacerbated by poor chemistry conditions. However, degradation of the reactor coolant pressure boundary is generally a long-term process and other direct means to monitor and correct reactor coolant pressure boundary degradation exist, which are controlled by regulations and plant technical specifications. For example, in-service inspection of components and primary coolant leakage limits are regulatory requirements that provide direct means to identify degradation of the reactor coolant pressure boundary. Therefore, requirements related to the chemistry program do not constitute initial conditions that are assumed in any design basis accident or transient related to reactor coolant system integrity.

The staff considers water chemistry to be an operational issue for plants. If a licensee frequently repairs or replaces components because poor chemistry practices are causing degradation, then that is a cost the licensee must incur. It is in the licensee's best interest to operate the plant with a chemistry regime that optimizes component performance. There is adequate industry-generated guidance available for licensees to develop a plant-specific water chemistry program. For example, the 2004 revision of the Electric Power Research Institute report BWRVIP-130: “BWR Water Chemistry” provides a framework for plant-specific chemistry programs. The industry routinely updates this guidance to incorporate the latest knowledge and lessons learned in the area of water chemistry.

II. Further Information

The withdrawal of RG 1.56 does not alter any prior or existing licensing commitments or conditions based on its use. The guidance provided in this regulatory guide no longer provides useful information. Regulatory guides may be withdrawn when their guidance is superseded by congressional action or no longer provides useful information.

Regulatory guides are available for inspection or downloading through the NRC's public Web site under “Regulatory Guides” in the NRC's Electronic Reading Room at​reading-rm/​doc-collections. Regulatory guides are also available for inspection at the NRC's Public Document Room (PDR), Room O-1 F21, One White Flint North, 11555 Rockville Pike, Rockville, Maryland 20852-2738. The PDR's mailing address is US NRC PDR, Washington, DC 20555-0001. You can reach the staff by telephone at 301-415-4737 or 800-397-4209, by fax at 301-415-3548, and by e-mail to

Regulatory guides are not copyrighted, and NRC approval is not required to reproduce them.

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Dated at Rockville, Maryland, this 4th day of February 2010.

For the Nuclear Regulatory Commission.

Andrea D. Valentin,

Chief, Regulatory Guide Development Branch, Division of Engineering, Office of Nuclear Regulatory Research.

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[FR Doc. 2010-3233 Filed 2-18-10; 8:45 am]