ML20086S146
| ML20086S146 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 07/27/1995 |
| From: | Querio R COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9508010116 | |
| Download: ML20086S146 (5) | |
Text
e p
l Commonw ealth Illiwm Q)mpany
- l.
LaSalle Generating Station 2601 North 21st Road Wrseilles, IL 613419757
- Td 8143574761 July 27,1995 United States Nuclear Regulatory Commission Washington, D.C. 20555 Attention:
Document Control Desk h
Subject:
LaSalle County Station Units 1 and 2 i
l Response to Notice of Violation Inspection Report Nos. 50-373/95004; 50-374/95004 NRC Docket Numbers 50-373 and 50 374.
Reference:
- 1. H.B. Clayton, letter to R.E. Querto, Dated June 30,1995, Transmitting j
NRC Inspection Report 50-373/95004; 50-374/95004.
I Enclosed is Comed's response to the Notice of Violation (NOV) that was transmitted with the Reference 1 letter and NRC Inspection Report Nos. 50-373/95004; 50-374/95004.
The Notice of Violation concerned loss of primary system coolant through the control rod drive system. The attachment to this letter contains the immediate corrective actions taken as well
{
as additional corrective actions which should be effective in precluding recurrence of the violation.
If there are any questions or comments concerning this letter, please refer them to me at (815) 357-6761, extension 3600.
1 i
Respectfully, R. E. Querio Site Vice President LaSalle County Station H. J. Miller, Regional Administrator, Region III cc:
W. D. Reckley, Project Manager, NRR P. G. Brochman, Senior Resident Inspector, LaSalle D. L. Farrar, Nuclear Regulatory Services Manager, NORS Central file 9508o10116 95o727 I
I l
PDR ADDCK 05000373 G
i PDR A Unicom comp.m>
e
t f
ATTACHMENT RESPONSE TO NOTICE OF VIOLATION NRC INSPECTION REPORT 50-373/95004, 50-374/95004 VIOLATION: 373(374)/95004-01a, b, c Title 10 of the Code offederal Regulations, Part 50, Appendix B, Criterion V, required that activities affecting quality shall be prescribed by documented procedures, of a type appropriate l
to the circumstances, and shall be accomplished in accordance with these documented procedures.
Procedure LOP RD-09, " Return of CRD System HCU to Service," Prerequisite C.4, required that the control rod drive (CRD) system to be in operation. The procedure was written to perform all of the necessary steps, one hydraulic control unit (HCU) at a time.
Contrary to the above:
a.
On March 19, 1995, LaSalle Operating Procedure LOP-RD-08, "CRD System HCU Isolation," was not appropriate to the circumstances in that it did not fully specify all valves to be tagged out of service (OOS) when isolating CRD HCUs.
b.
On March 19,1995, LOP-SF-06, " Filling the Reactor, R.eactor Well and Dryer / Separator Pit Through Feedwater with Suppression Pool Cleanup," was not appropriate to the circumstances in that it assumed that re-filling of the reactor vessel would occur from normal reactor level (+30 inches). However, the procedure was used to re-fill the reactor vessel following the recirculation system decontamination (-200 inches level).
Consequently, system interconnections below the normal reactor water level were not considered by the procedure, c.
On March 19,1995, the CRD system was not in operation while retuming CRD HCUs to service. Also, the valve manipulations were done in aggregate for all of the HCUs, rather than restoring one HCU at a time.
This is a Severity IV violation (Supplement I).
2
ATTACHMENT RESPONSE TO NOTICE OF VIOLATION NRC INSPECTION REPORT 50-373/95004, 50-374/95004 REASON FOR VIOLATION: 373(374)/95004-01 On March 19,1995, Comed identified that approximately 2500 gallons of reactor coolant had spilled onto the floor of the reactor building. The spill resulted from 24 open valves on control rod drive (CRD) hydraulic control units (HCU). This evolution occurred while operators were refilling the reactor vessel following the chemical decontamination of the reactor recirculation piping. The reactor was defueled and was in the process of being refilled prior to conducting additional outage activities. The equipment alignment status resulting from several 2
parallel evolutions creating a drain path, whereby 1800 ft of reactor building floor area became radiologically contaminated. This event is considered significant because of the loss of plant configuration control, the level of radiological contamination, and the dose (approximately 300 MREM) required to decontaminate the area.
The root cause of this event is attributed to a procedural deficiency which resulted in a failure to adequately control plant configuration. Procedure LOP-RD-08 did not require the Accumulator Water Side Drain valve (2Cll-D001-107) to be taken out of service in the open position.
A contributing factor was a lack of follow-through on the part of the Operations Shift Management involved in the fill process evolution, since an adequate review of the procedure was not performed to determine ifit was sufficient for the task to be performed. This is considered a significant factor, in that if the procedure had the adequate scope to cover the activity, additional administrative barriers would have been in place to prevent this event, i
Operations management did not pay adequate attention to the concerns raised by j
equipment attendants in regards to the configuration of valves in the CRD System. The equipment attendants took actions that were both reasonable and conservative, by calling an off-normal situation to the attention of their supervisor. The supervisor did not follow through and determine what the net impact of the off-normal valve positions would be, and assumed that the mechanical checklist or precharging activities would be performed in a timely fashion. The equipment attendants took further actions that were both reasonable and conservative, in that they called an off-normal situation to the attention of the Outage Director, The Outage Director did j
not determine what the net impact of the off-normal valve positions would be, and also assumed that the mechanical checklist or precharging activities would be performed in a timely fashion.
The fact that the input of members of plant staff was dismissed without adequate review raises important concerns since communications were attempted on two separate occasions, and the information was either dismissed or explained away without adequate research. This is not consistent with the conservative decision making philosophy that must be in place to assure safe plant operations.
3 i
g F
y*.
ATTACHMENT RESPONSE TO NOTICE OF VIOLATION NRC INSPECTION REPORT 50-373/95004, 50-374/95004 CORRECTIVE ACTIONS TAKEN AND RESULTS ACHIEVED:
(373(374)/95004-01)
On March 19,1995, the Operations shift crew cleared out of service no. 950001826 on the Scram Instrument Air Header. This allowed repressurization of the Scram Air Header, which further isolated the Reactor Vessel from the drain path by closing Scram Valves 126 and 127.
As an additional measure, operators were dispatched to close all open Accumulator Water Side Drain Valves 2Cll-D001-107 and CRD Scram Discharge Stop valves 2Cll-D001-ll2.
Subsequent to the event, the following actions were taken:
- 1. The Operations Manager and designee conducted briefings with all Operations crews, emphasizing the serious nature of this event.
- 2. Procedure LOP-RD-08 was revised on April 29,1995, to include specific guidance to take the CRD Accumulator Water Side Drain Valves (107) out of service in the open position.
- 3. Lessons Learned Information Notification (LLIN)95-036 was issued April 3,1995 to communicate this event to all Operations personnel and other Comed nuclear sites.
- 4. The LLIN process was changed to Nuclear Operations Notification (NON) on May 2,1995 to expedite the notification process. This NON function is directed by the Independent Safety Engineering Group (ISEG) at the Station under Site Quality Verification to formalize the review process for the Lessons Leamed system, and provide screening and resolution of applicable issues at LaSalle.
- 5. Conservative decision making seminars were conducted for all operating crews. These sessions were undertaken to raise the level of questioning attitudes and help management realize the importance oflistening to workers. These sessions were mentored by the Site Vice President and the Executive Vice President BWR and were concluded on April 20,1995.
4 l
I
(
i ATTACHMENT RESPONSE TO NOTICE OF VIOLATION NRC INSPECTION REPORT 50-373/95004, 50-374/95004 CORRECTIVE ACTIONS TO BE TAKEN TO AVOID FURTHER VIOLATIONS:
(373(374)/95004-01)
Ongoing activities include: incorporating NONs in operator training, senior management coaching of all Operating crews on the need to maintain a questioning attitude, stressing the need for conservative decision making, the necessity of procedural use and adherence, and coaching of outage managers and planners on the need to better integrate related activities. In addition, the following actions are to be taken:
'l.
A review will ba undertaken to address the overall adequacy of our Control Rod Drive System procedures.
- 2. A review will be conducted of other plant systems to ensure that when vents and drain paths are reconfigured, they are tracked by the out of service process (or equivalent means) to ensure that knowledge and control of configuration will be maintained.
- 3. Procedure LOP-SF-06 will be revised to reflect filling the reactor vessel from a drained condition.
DATE WIIEN FULL COMPLIANCE WILL BE ACIIIEVED (373(374)/95004-01):
Full compliance was achieved on March 19,1995 when the quick disconnect drain hoses downstream of the Accumulator Water Side Drain Valves (2Cll-d001-107) were removed. This action terminated the draining event. As an additional measure, operators closed all open i
Accumulator Water Side Drain valves 2Cll-D001-107 and CRD Scram Discharge Stop valves 2Cl1-D001-112.
i 5