IR 05000456/1993012
| ML20045A841 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 06/08/1993 |
| From: | Farber M NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20045A840 | List: |
| References | |
| 50-456-93-12, 50-457-93-12, NUDOCS 9306150054 | |
| Download: ML20045A841 (7) | |
Text
.
,
t t
U.S. NUCLEAR REGULATORY COMMISSION
REGION III
l
.
Reports No. 50-456/93012(DRP); 50-457/93012(DRP)
Docket Nos. 50-456; 50-457 Licenses No. NPF-72; NPF-77 Licensee:
Commonwealth Edison Company Opus West III 1400 Opus Place Downers Grove, IL 60515
,
Facility Name:
Braidwood Station, Units 1 and 2
,
Inspection At:
Braidwood Site, Braidwood, Illinois Inspection Conducted: April 14 through May 25, 1993 Inspectors:
S. G. Du Pont J. R. Roton
Approved By:
,
M. Farbg'r, Chief Date Reactor Projects Section lA
'
Inspection Summary Inspection from April 14 throuah May 25. 1993 (Reports No. 50-456/93012(DRP):
50-457/93012(DRP))
Areas Inspected:
Routine, unannounced safety inspection by the resident inspectors of licensee event report review; operational safety verification;
,
monthly maintenance observation; report review and meetings.
Results:
A non-cited violation is discussed in Paragraph 2.
The details of the
event and licensee actions were previously discussed in Inspection Report 50-456/93004(DRP); 50-457/93004(DRP).
The licensee's actions associated with the Unit 2 fuel failure are
considered to be conservative and responsive in ensuring that allowable Technical Specification limits were not reached or exceeded.
,
,
t
h 9306150054 930608 PDR ADOCK 05000456 G
.
. -
.
.
-
.
-
~
.
F DETAILS
,
,
1.
Persons Contacted Commonwealth Edison Company (Ceco)
,
S. Berg, Vice President
,
R. Flessner, Executive Assistant
,
- K. L. Kofron, Station Manager
~
R. Stols, Services Director
- A. Haeger, Regulatory Assurance Supervisor
"
G. R. Masters, Engineering and Construction Manager
- D. E. Cooper, Operations Manager G. E. Groth, Maintenance Superintendent R. Byers, Assistant Superintendent Work Planning
>
- D. Miller, Technical Services Superintendent G. Pliml, Quality Verification Manager G. Vanderheyden, System Engineering Supervisor S. Roth, Security Supervisor K. G. Bartes, Quality Verification Superintendent
,
- J. Lewand, Regulatory Assurance
- Denotes those attending the exit interview conducted on May 25, 1993.
The inspectors also interviewed.several other licensee employees.
2.
Licensee Event Report (LER) Review (92700)
LERs were reviewed and closed based on the following criteria:
.
Reportability requirements were met.
,
Immediate corrective actions were accomplished.
'
'
Corrective actions to prevent recurrence have been or will be
initiated per technical specifications.
(Closed) 457/93002: April 14,1993, Unit 2 Unplanned Engineered Safety i
Feature (ESF) actuation due to management and procedural deficiency.
,
Braidwood System Engineering was conducting surveillance activities
-
stroking the safety injection (SI) accumulator isolation valves. While these activities were being conducted,.the Operating Department was aligning electrical equipment to support testing of the 2A diesel generator. During this transfer, it was unknown that the instrument bus l
!
would be momentarily de-energized.
'
One non-cited violation was identified.
!
i
.
P
.
,
.
This transfer was conducted per procedure Bw0P IP-1, Instrument Bus Inverter Startup. However, the procedure did not contain an appropriate precaution that swapping power supplies could cause a reactor trip due to momentary loss of power to the source and intermediate range nuclear instrumentation.
As the power supplies were being swapped, the Nuclear Station Operator (NS0) immediately noticed increasing pressurizer level (about 50% level increase to 98%). The NSO took immediate action to stop the power supply swapping and closed the SI accumulator isolating valves for the A and D accumulators.
The unit was shut down and cold at about 90 pounds pressure.
Subsequent review revealed that procedure Bw0P IP-1 was inappropriate and that supervisors failed to recognize the possibility of an ESF actuation while conducting the two activities concurrently.
The licensee's immediate actions prevented filling the pressurizer solid.
Subsequent actions included revising operating procedure Bw0P IP-1 and evaluating the scheduling of activities. The licensee identified and corrected the errors associated with the event. This is a non-cited violation per 10 CFR 2, Appendix C, Section VII.B.(2).
3.
Operational Safety Verification (71707)
The inspectors verified that the facility was being operated in conformance with the licenses and regulatory requirements and that the licensee's management control system was effectively carrying out its responsibilities for safe operation.
No violations or deviations were
identified.
Unit 1 entered the inspection period at normal operating power.
No problems or events occurred. Operations personnel were effective and professional.
Unit 2 entered the inspection period in the final phase of a scheduled refueling outage. The unit was taken critical on April 30, 1993, and
low power physics testing was conducted through May 7, 1993.
On May 16, 1993, the Technical Specification daily Reactor Coolant System Sample indicated that a fuel element potentially had a cladding defect.
The following events were related to the fuel failure event:
Iodine levels increase.
- Technical Specification limits.
- Operating history.
- May 17 sample confinns fuel failure.
- Licensee Actions per BwAP 2364-11.
- Management involvement.
- Iodine response May 17-25.
- _
.
-
- - -
.
_
_
.
NRC response.
- Long term actions.
- Safety significance.
- On May 16, 1993, the Unit 2 Reactor Coolant System (RCS) sample indicated an increase in Iodine (I-131) and measured Dose Equivalent Iodine. The previous Dose Equivalent Iodine levels were about.004 micro-curie per gram of iodine.
The measured sample on May 16 was about
.0080 micro-curie per gram. This was interpreted by the licensee as an initial indication of a possible fuel element failure.
Technical Specification (TS) 3.4.8 limits specific activity in the RCS to 1.0 micro-curie per gram Dose Equivalent I-131.
The TS also allows a 48 hour5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br /> period to reduce the specific activity to less than one micro-curie per gram prior to initiating a reactor shutdown. The bases for these limits are to ensure that the resulting two-hour doses at the site
boundary will not exceed an appropriately small fraction (less than 2%)
of 10 CFR Part 100 dose guideline values following a steam generator
,
tube rupture accident in conjunction with an assumed steady-state l
primary to secondary steam generator leakage rate of one gallon per minute.
The operating history of Unit 2 revealed that the unit had recently returned from a scheduled refueling outage. The unit was taken critical on April 30, 1993. Daily RCS samples did not indicate any rapid change in specific activity until May 16, 1993.
The sample on May 17, 1993, confirmed that Iodine activity was i
'
increasing due to the failure of one or more fuel elements. The measured Dose Equivalent Iodine on May 17, 1993, was about.082 micro-curies per gram.
The licensee entered the appropriate action level (Level 3) per Administrative Procedure BwAP 2364-11, Failed Fuel Action Plan.
The
,
licensee initiated increased sampling frequency from daily to every two hours. This action is conservative compared to TS requirements of
,
sampling once every four hours.
The procedure also required approval j
from a Vice President in the Nuclear Operations Division to allow operation beyond seven days from entry into the action level.
Licensee management initiated several actions. An intermediate action
level of.600 micro-curies per gram Dose Equivalent Iodine was selected
-
to initiate the TS actions. This was conservative compared to the 1.00 micro-curies per gram TS level. Management also tasked various departments: Health Physics, Radiation Protection, Chemistry, Operations, Maintenance, and System Engineering to evaluate the effects of the elevated RCS activity on continued operation.
The licensee also evaluated the operating history of other facilities that experienced similar fuel element failures.
.
'
.
,
The licensee initiated daily onsite review meetings to evaluate the RCS activity and effects on continued operation. On May 18, 1993, the information pertaining to continued operation, such as increased
'
background dose rates in specific locations within the plant, was provided to all plant personnel. Daily updates were provided through May 23, 1993.
The As-Low-As-Reasonably-Achievable (ALARA) concerns were addressed and provided to plant personnel on May 19, 1993. One of the actions presented included that a member of the ALARA Group was assigned i
responsibility for reviewing all activities scheduled in affected areas
,
of Unit 2 to recommend methods for minimizing personnel exposures.
Another. action included-reviewing operator rounds to determine if installation of video cameras in the affected areas was possible. These
<
actions were considered to be appropriate.
Weekly onsite review meetings were also initiated to evaluate and recommend, to CECO Nuclear Operations Division, the availability of the unit for continued operations.
It should be noted that these actions are significantly more than required by Technical Specifications, j
.
'
The Iodine Dose Equivalent trended up from May 16 to May 18, 1993, and then started a slow decay.
The measured Dose Equivalent Iodine trend is as below:
!
Dose Eouivalent I-131 Date Time (Micro-curies per aram)
5/16/93 0730
.008 5/17/93 0730
.082 5/17/93 1700
.327 5/18/93 0300
.487
,
5/18/93 0730
.539 5/18/93 0930
.548 5/18/93 1100
.510 5/18/93 1500
.510
'
5/18/93 2100
.500 5/19/93 0300
.477
5/19/93 0770
.454 5/20/93 0000
~.400 5/21/93 0000
~.400
<
5/22/93 2105
.246 5/23/93 1215
.236 j
5/24/93 0015
.228 5/25/93 0000
.180 The trend indicated that the peak occurred on May 18, 1993 at about.539 micro-curies per gram Dose Equivalent I-131.
The Nuclear Regulatory Commission (NRC), Region III increased monitoring
'
and inspection on May 17, 1993.
Initially, the Division of~ Reactor Projects (DRP) was notified by the licensee through the Resident
- -
,
-
.
,
Inspectors. Appropriate DRP management was informed of. the licensee's -
actions including results of their daily meeting.
Frequent
!
communications between the licensee's site management to DRP management
were maintained throughout the night of May 17, 1993 through the NRC residents. Additional direct communications between the licensee's Site Vice President and the appropriate DRP Branch Chief were also maintained in parallel to ensure prompt and accurate communications.
These
communications pertained to the results of the increased sampling and
,
the licensee's actions and plans.
l The residents attended daily briefings with the licensee's site
management from May 17,.through May 21, 1993. The residents also independently verified that the affected areas within the plant were identified to plant operating personnel.
The residents discussed the Iodine trend and licensee's actions with the Regional Administrator, Region III on May 21, 1993.
On May 24, 1993, the Division of Reactor Safety and Safeguards (DRSS),
Region III dispatched a Health Physics specialist to evaluate the effects of the elevated dose Equivalent I-131. The Dose Equivalent I-131 had decayed to about.228 micro-curies per gram on May 24, 1993.
The licenseo's long term actions include weekly onsite safety review meetings to evaluate continued operations. Other long term concerns include increasing the change-out frequency of RCS filters and
. - demineralizers, use of remote monitoring. devices, and increased shielding for maintenance activities.
The safety significance of the event was bounded by Technical Specifications (TS) and 10 CFR Part 100.
TS requirement of one micro-curies per gram ensures that a small fraction (about 1%) of 10 CFR 100 limits will not be exceeded during an accident involving a steam generator tube rupture. The licensee imposed an administrative limit of
.6 micro-curie per gram to ensure not exceeding the TS limit.
Additionally, Figure 3.4-1 of TS allows exceeding the one micro-curie
,
per gram limit up to 48 hours5.555556e-4 days <br />0.0133 hours <br />7.936508e-5 weeks <br />1.8264e-5 months <br />, but not greater than 72 micro-curies per
!
gram at 100% of rated thermal power. A reduction of thermal power to l
70% would allow 100 micro-curies per gram.
.
4.
Monthly Surveillance Observation (61726)
l The inspectors observed several of the surveillance tests required by
technical specifications during the inspection period and verified that testing was performed in accordance with adequate procedures, that test instrumentation was calibrated, that results conformed with technical specifications and procedure requirements and were reviewed, and that
-
any deficiencies identified during the testing were properly resolved.
No violations or deviations were identified.
l
'
,
,
&
.
.
.
,
The following surveillance activities were observed and reviewed:
.
BwVS 1.3.4-1, Unit 2 Rod Drop Time
BwVS 4.10-3.1, Unit 2 Visual Examination of Class 1 Components
(N0P)
BwVS 4.10-3.4, Hydrostatic Examination
Bw0S 1.1.1.1.e-1, Shutdown Margin Daily Verification
Bw05 1.1.1.1.c-1, Predicted Critical Rod Position
'
BwGP 100-7T4, Estimated Critical Calculation
Unit 2 Mode changed from Mode 3 to Mode 2
-
Unit 2 Mode changed from Mode 2 to Mode 1
5.
ReDort Review During the inspection period, the inspector reviewed the licensee's Monthly Performance Report for April 1993. The inspector confirmed that the information provided met the requirements of Technical Specification 6.9.1.8 and Regulatory Guide 1.16.
The inspector also reviewed the licensee's Monthly Plant Status Report for April 1993.
No violations or deviations were identified.
'
6.
Violations for Which A " Notice of Violation" Will Not Be Issued The NRC uses the Notice of Violation as a standard method for
"
formalizing the existence of a violation of a legally binding requirement. However, because the NRC wants to encourage and support licensee's initiatives for self-identification and correction of problems, the NRC will not generally issue a Notice of Violation for a violation that meets the tests of 10 CFR. 2, Appendix C, Section V.A.
These tests are:
1) the violation was identified by the licensee; 2)
the violation would be categorized as Severity Level IV or V; 3) the
,
violation will be corrected, including measures to prevent recurrence, within a reasonable time period; and 4) it was not a violation that i
could reasonably be expected to have been prevented by the licensee's corrective action for a previous violation. A violation of regulatory
-
requirements identified during this inspection for which a Notice of Violation will not be issued is discussed in Paragraph 2.
7.
Exit Interview (30703)
The inspectors met with the licensee representatives denoted in Paragraph I during the inspection period and at the conclusion of the inspection on May 25, 1993.
The inspectors summarized the scope and results of the inspection and discussed the likely content of this
'
inspection report.
The licensee acknowledged the information and did not indicate that any of the information disclosed during the inspection could be considered proprietary in nature.
7