IR 05000261/1986004
| ML14175B363 | |
| Person / Time | |
|---|---|
| Site: | Robinson  |
| Issue date: | 02/27/1986 |
| From: | Conlon T, Gibbons T NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | |
| Shared Package | |
| ML14175B362 | List: |
| References | |
| 50-261-86-04, 50-261-86-4, NUDOCS 8603110225 | |
| Download: ML14175B363 (3) | |
Text
tyn" REGu UNITED STATES NUCLEAR REGULATORY COMMISSION
REGION II
101 MARIETTA STREET, &t ATLANTA, GEORGIA 30323 Report No.:
50-261/86-04 Licensee:
Carolina Power and Light Company P. 0. Box 1551 Raleigh, NC 27602 Docket No.:
50-261 License No.:
DPR-23 Facility Name: H. B. Robinson Inspection Conducted: January 29-30, 1986 Inspector:
C *
T. D. Gibbons Date Signed Approved by:
T. E. Conlon, Section Chief Date Signed Engineering Branch Division of Reactor Safety SUMMARY Scope:
This routine, unannounced inspection involved 16 inspector-hours on site in the areas of followup on the licensee event of loss of offsite power on January 28, 1986, and inspector followup ite Results:
No violations or deviations were identifie i0225 8760304 3m PDR ADOCK 05000261 G
REPORT DETAILS Persons Contacted Licensee Employees
- J. M. Curley, Acting Plant General Manager
- H. J. Young, Director, Quality Assurance/Quality Control (QA/QC)
- J. C. Sturdavant, Technician, Regulatory Compliance
- G. Honma, Senior Specialist, Regulatory Compliance NRC Resident Inspector
- H. Krug, Senior Resident Inspector
- Attended exit interview Exit Interview The inspection scope and findings were summarized on January 30, 1986, with those persons indicated in paragraph 1 abov The inspector described the areas inspected that related to the loss of offsite power. The licensee did not identify as proprietary any of the materials provided to or reviewed by the inspector during this inspectio.
Licensee Action on Previous Enforcement Matters This subject was not addressed in the inspectio.
Unresolved Items Unresolved items were not identified during the inspectio.
Followup on Licensee Event The inspector was sent to the plant to assist the resident inspector in evaluating the loss of offsite power (LOSP)
incident which occurred on January 28, 1986. This incident is still being evaluated by the licensee and his contractor On January 28, 1986, the plant tripped from 80% power at 9:17 The licensee believes that high pressurizer pressure caused the reactor tri The cause of the high pressurizer pressure was a fault on emergency bus E-2 which resulted in a voltage spike on Instrument bus 4. The voltage spike on Instrument bus 4 initiated a main turbine runbac The runback caused a pressure transient which initiated the reactor tri The main generator is kept on line for 60 seconds after the reactor trips then oil circuit breakers (OCB)
52/8 and 52/9 opened in the 230 Kv switch yar Load dispatcher records indicate that the 115 KV switchyard tripped at the same time as the OCBs. This removed power from the 115 KV switchyard de-energizing the startup transformer. When the OCBs are opened, the three 4160 buses which are normally fed from the auxiliary transformer automatically switched to the startup transforme When this switching occurred, the startup transformer was no longer receiving power from the 115 KV switchyar This action resulted in a total LOS Emergency diesel generator (EDG) A started and loaded on 480 volt emergency bus El and the A train safety systems functioned as designed and the plant was brought safely to hot shutdown. The B train EDG was out of service for routine maintenance and was restored to service in about half an hou The licensee reported that the incident was terminated by reconnecting to the offsite power at 16:03 on January 2 The unit was placed in hot standby and then brought to cold shutdown on January 30, 1986, when the decision was made to start the scheduled refueling outag The licensee has identified that the loss of bus E-2 was caused by a degraded grid relay which tripped the bus E-2 feeder breaker. The cause of the 115 KV switchyard appears to be a phase C phase differential relay which protects the startup transformer. The licensee has not determined the cause of the phase differential tri The licensee has set up an extensive testing program to identify the phase differential proble The Senior Resident Inspector is following this problem on inspector followup item 86-01-0.
Inspector Followup Item (Closed) IFI 84-18-01, Review of the Requalification Program of I&C Technicians and Electricians The licensee has issued Training Instruction (TI) 113, "Replacement Training for I&C Technicians and Electricians".
The licensee stated that the training program was accredited by INPO in December 1985. The inspector examined the training records of six I&C technicians and four electricians. The records identified the formal training given to each individual. A separate record identifies the on-the-job training given the individual and signature of supervisor who certifies the employer in the job area.