IR 05000255/2001015
| ML020650367 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 03/04/2002 |
| From: | Grobe J Division of Reactor Safety III |
| To: | Cooper D Nuclear Management Co |
| References | |
| EA-02-011, FOIA/PA-2013-0250 IR-01-015 | |
| Download: ML020650367 (34) | |
Text
March 4, 2002
SUBJECT:
PALISADES NUCLEAR GENERATING PLANT NRC SPECIAL INSPECTION REPORT 50-255/01-15
Dear Mr. Cooper:
On January 29, 2002, the NRC completed a Special Inspection at your Palisades Nuclear Generating Plant regarding an active steam/primary coolant system leak from a through-wall crack in the upper housing assembly for Control Rod Drive Mechanism 21. The enclosed report documents the inspection findings which were discussed on January 29, 2002, with you and other members of your staff.
Beginning on about June 9, 2001, your staff detected and monitored an increase in primary coolant system leakage until the plant was shut down from full power to Hot Standby (Mode 3)
on June 20, 2001. On June 21, 2001, a member of your staff and a resident inspector identified an active steam/primary coolant system leak from Control Rod Drive Mechanism (CRDM) 21. Your staff subsequently placed the plant in cold shutdown and assembled a team to evaluate the occurrence, assess extent of condition, determine root cause, and develop strategies for restoration. Non-destructive examination revealed an axially-orientated flaw at the eccentric reducer to pipe weld on the housing of CRDM 21. During subsequent examinations, indications of cracks were identified on multiple additional control rod drive mechanism housings caused by transgranular stress corrosion cracking. To correct this condition, your staff replaced all 45 CRDM housings.
This inspection examined activities conducted under your license as they relate to safety and compliance with the Commissions rules and regulations and with the conditions of your license.
The inspectors reviewed selected procedures and records, observed activities, and interviewed personnel. Seven violations of regulatory requirements were identified during this inspection.
The root cause of these violations appears to include contributions from human performance errors. Deficiencies in human performance can impact multiple reactor safety cornerstones and cause an adverse impact on safe plant operation. As such, human performance represents a fundamental underpinning of the reactor safety cornerstones. A significant cross-cutting human performance finding was identified associated with these violations in that multiple examples of inadequate engineering products were identified which provided a technical bases for modifications, operability evaluations and corrective actions. This performance deficiency reflects a lack of rigor applied to performing and verifying mechanical, structural, and metallurgical engineering work that affected the reactor safety cornerstones for initiating event frequency, barrier integrity, and mitigating systems. We are concerned that without NRC intervention, inadequate modifications may have been installed and/or that degraded equipment would have been returned to service without an adequate basis to confirm operability. Your on-going effort to perform a comprehensive review to identify and correct the causes of this adverse trend in human performance is important to ensure the integrity of the plant design basis.
The seven violations are categorized as Green findings of very low safety significance.
Because of their very low safety significance and because these issues were entered into your corrective action program, the NRC is treating these issues as Non-Cited Violations (NCVs) in accordance with Section VI.A.1 of the NRCs Enforcement Policy. If you deny these Non-Cited Violations, you should provide a response with a basis for your denial, within 30 days of the date of this inspection report, to the Nuclear Regulatory Commission, ATTN: Document Control Desk, Washington, DC 20555-0001, with copies to the Regional Administrator, Region III; the Director, Office of Enforcement, United States Nuclear Regulatory Commission, Washington, DC 20555-0001; and the NRC Resident Inspector at the Palisades Nuclear Generating Plant.
An additional violation of Technical Specification 3.4.13 was identified for plant operation greater than 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> with leakage from the cracked CRDM 21 housing. Although this issue constitutes a violation of NRC requirements, it did not have actual safety consequences (as defined in Section IV.A.5.c of the Enforcement Policy), impede the regulatory process, or result from willful acts. Additionally, your staffs actions did not contribute to the degraded condition and the leakage resulted from material failure not avoidable through reasonable quality assurance measures or management controls. Consequently, no performance deficiency was identified. Based on these facts, the NRC has decided to exercise enforcement discretion in accordance with Section VII.B.6 of the Enforcement Policy and refrain from issuing enforcement action for the violation. A deterministic risk assessment considering fracture mechanics structural margins determined that this was an issue of very low safety significance. In accordance with 10 CFR 2.790 of the NRC's "Rules of Practice," a copy of this letter and its enclosure will be available electronically for public inspection in the NRC Public Document Room or from the Publicly Available Records (PARS) component of NRC's document system (ADAMS). ADAMS is accessible from the NRC Web site at http://www.nrc.gov/NRC/ADAMS/index.html (the Public Electronic Reading Room).
Sincerely,
/RA/
John A. Grobe, Director Division of Reactor Safety Docket No. 50-255 License No. DPR-20 Enclosure:
Inspection Report 50-255/01-15(DRS)
cc w/encl:
R. Fenech, Senior Vice President, Nuclear Fossil and Hydro Operations L. Lahti, Manager, Licensing R. Anderson, Chief Nuclear Officer, NMC A. Udrys, Esquire, Consumers Energy Company S. Wawro, Nuclear Asset Director, Consumers Energy Company W. Rendell, Supervisor, Covert Township Office of the Governor Michigan Department of Environmental Quality Department of Attorney General (MI)