NUCLEAR REGULATORY COMMISSION
OFFICE OF NUCLEAR REACTOR REGULATION
WASHINGTON, D.C. 20555-0001
April 20, 1998
|NRC INFORMATION NOTICE 98-13:||POST-REFUELING OUTAGE REACTOR PRESSURE VESSEL LEAK TESTING BEFORE CORE CRITICALITY|
All holders of operating licenses for nuclear power reactors except those that have permanently ceased operations and have certified that fuel has been permanently removed from the reactor vessel.
The U.S. Nuclear Regulatory Commission (NRC) is issuing this information notice to alert addressees of the requirement to complete pressure tests and leak tests of the reactor pressure vessel (RPV) before core criticality. It is expected that recipients will review the information for applicability to their facilities and consider actions, as appropriate, to avoid similar problems. However, suggestions contained in this information notice are not NRC requirements; therefore, no specific action or written response is required.
Under the American Society of Mechanical Engineers Boiler and Pressure Vessel Code (ASME Code) , Section XI, Class 1 and 2 leakage tests provide a level of defense-in-depth for detecting pressure boundary leakage. From a safety perspective, performing this test using nuclear heat defeats the intended purpose of ensuring the integrity of the RPV as a fission product barrier.
A December 1995 rule change to Part 50 of Title 10 of the Code of Federal Regulations (10 CFR Part 50), Appendix G, Section IV.A.2.d, clarified the staff position as follows: "Pressure tests and leak tests of the reactor vessel that are required by Section XI of the ASME Code must be completed before the core is critical." The final rule was published in the Federal Register on December 19, 1995. In addition, the Federal Register notice referenced a letter to Messrs. Reynolds and Stenger of the Nuclear Utility Backfitting and Reform Group (NUBARG) from James M. Taylor, NRC Executive Director for Operations, dated February 2, 1990, in which Mr. Taylor discussed the explicit prohibition of using nuclear heat to perform pressure and leak tests (Accession Number 9002120362).
Description of Circumstances
On June 22, 1997, the licensee for Quad Cities Station performed the required ASME Code, Section XI leak test of the RPV following Unit 2 criticality and startup from a refueling outage.
The reactor was at approximately 12-percent power. On October 1, 1997, while reading Appendix G for guidance on a separate issue, the licensee discovered that it had violated the requirement to complete pressure and leak testing before the core is taken critical.
In December 1997, a Region III inspector reviewed (1) ASME Code Class 1 system pressure tests for the Quad Cities Units 1 and 2 refueling outage 14 and (2) problem identification forms (Inspection Report 50-254/97-27, Accession Number 9803170418). The licensee had previously documented the violation that took place on June 22, 1997, of Appendix G requirements in one of the problem identification reports. The Inspector found that the visual VT-2 examinations of the Unit 2 drywell area required by the ASME Code were conducted in a very short time. In an effort to keep exposure time to a minimum, licensee personnel covered very large examination areas in a very short time (e.g., 50 examination areas in 12 minutes). The short examination time called into question the adequacy of the visual VT-2 examinations.
The NRC and the licensee discussed apparent violations during an open, predecisional enforcement conference that took place on January 9, 1998. On March 12, 1998, the NRC issued a Notice of Violation and Proposed Imposition of Civil Penalty in the amount of $330,000 for violations of Appendix G to 10 CFR Part 50, 10 CFR 50.59, and Technical Specification surveillance requirements.
This issue is of significant concern because licensees should recognize that the intent of performing the ASME Code pressure and leak tests before the reactor is taken critical is to ensure the integrity of the RPV without using nuclear heat. The staff's position has been, and continues to be, that performing pressure and leak tests after the core is critical is unacceptable. This point was clarified in the December 1995 rule change.
This information notice requires no specific action or written response. However, recipients are reminded that they are required to consider industry-wide operating experience (including NRC information notices) when practical and when setting goals and performing periodic evaluations under 10 CFR Section 50.65, "Requirement for Monitoring the Effectiveness of Maintenance at Nuclear Power Plants," If you have any questions about the information in this notice, please contact one of the technical contacts listed below or the appropriate Office of Nuclear Reactor Regulation (NRR) project manager.
|/s/'d by D. B. Matthews
Jack W. Roe, Acting Director
|Technical contacts:||Andrea D. Lee, NRR |
Melvin Holmberg, RIII
(NUDOCS Accession Number 9804150187)