05000499/LER-1997-003, :on 970224,TS SR 4.5.2 Was Not Met When Loose Debris Was Discovered in Reactor Containment Bldg.Caused by Failure to Communicate Mgts Expectation.Loose Debris Was Removed
| ML20138G695 | |
| Person / Time | |
|---|---|
| Site: | South Texas  |
| Issue date: | 04/28/1997 |
| From: | Head S HOUSTON LIGHTING & POWER CO. |
| To: | |
| Shared Package | |
| ML20138G668 | List:
|
| References | |
| LER-97-003, LER-97-3, NUDOCS 9705060363 | |
| Download: ML20138G695 (4) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(iv), System Actuation 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| 4991997003R00 - NRC Website | |
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NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150-0104 14 95)
EXPIRES 04/30/98 ESTI"ATED BURDEN PER CESPONSE TO COCPLY CITH THIS CANDATORV lNFORMA110N COLLECTION REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED ARE LICENSEE EVENT REPORT (LER)
INCORPORATED WTO THE UCENSING PROCESS AND FE0 BACl( TO INDUSTRY.
FORWARD COMMENTS REGARDING BURDEN ESilMATE TO THE INFORMAtl0N AND 3
RECOR05 MANAGEMENT BRANCH (T.6 F33L U.S. NUCLEAR REGULATORY COMMISSION.
(See reverse for required number of WASHINGTON, DC 205550001. AND TO THE PAPERWORK REDUCTION PROJECT 0150-digits / characters for each block) 0104L OFFICE OF MANAGEMENT AND BUOGET. RASHINGTON. DC 20503.
FOC4LITY NAME II)
DOCKET NUMBER (2)
PAGE 131 South Texas, Unit 2 05000 499 1 OF 4 TITLE W Failure to meet the requirements of Technical Specification 4.5.2.c regarding surveillance inspection of containment for loose debris.
EVENT DATE (5)
LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED (8)
FACILIIY NAMk DOCKET NUMBLR SE
^L N
MOMTH DAY YEAR YEAR MONTH DAY YEAR NU E NU R
FACluTY NAME DOCKET NUMBER 02 24 97 97 -- 003 --
01 04 28 97 l
05000 l
OPERATING THIS -REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR 5: (Check one or more) (11) 3 MODE (9) 20.2201(b) 20.2203(aH2Hv)
X 50.73(aH2)(o 50.73(a)(2Hvuo POWER 0
LEVEL (10) 20.2203(a)(2H0 20.2203(aH3Hu) 50.73(aH2Hm) 73.71 20.2203(aH2)(u) 20.2203(aH4) 50.73(a)(2)(iv)
OTHER g.
20.2203(a)(2)(ud 50.36(c)(1) 50.73(a)(2)(v)
Specify in Abstract below 20.2203(a)(2)(av) 50.36(c)(2) 50.73(aH2Hvu)
LICENSEE CONTACT FOR THIS LER (12)
NAME TELEPHONE NUMBER Unclude Area Cocal Scott M. Head (512) 972-7136 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
REPORTABLE REPORTAD E
CAUSE
SYSTEM COMPONENT MANUFACTURER
CAUSE
SYSTEM COMPONENT MANUFACTURER SUPPLEMENTAL REPORT EXPECTED (14)
MONTH DAY YEAR EXPECTED YES SUBMISSION X NO (if yes, complete EXPECTED SUBMISSION DATE).
DATE (15)
ABSTRACT (Limit to 1400 spaces. Le., approximately 15 single-spaced typewritten knes) (16)
On february 24,1997, Unit 2 was in Mode 3 following core refueling. It was determined that Technical Specification Surveillance Requirement 4.5.2.c, as defined in the surveillance procedure, was not met when loose debris was discovered in the Reactor Containment Building. Additional discoveries of miscellaneous small items of loose debris were made on March 27.1997 during numerous walk-downs following a reactor trip. All of the items discovered were with activities that were performed during the previous outage period. Based on this,y were discover immediately removed. The types of items discovered and the locations in which the these most recent discoveries are associated with the previous event. The corrective actions associated with the previous event are still ongoing and, when combined with the additional corrective action in this supplement, will prevent this type of event in the future.
Evaluations performed for the previous discovery and these subsequent discoveries have determined that the Emergency Core Cooling System would not have been compromised during a design bases event with these items in contamment. In all cases the Emergency Core Cooling System was operable.
9705060363 97042G PDR ADOCK 05000499 S
PDR NRC FORM 366 (4-95) e we om,,,,
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NRC FAM 366A U.S. NUCLEAR REGULATORY CoMMISSloN 149M LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
~
DOCKET LER NUMBER (6) l PAGE (3)
YEAR SEQUENTIAL REVISION South Texas, Unit 2 05000 499 2
OF 4
97 -- 003 --
01 TEXT (if more space is required, use additional copies of NRC Form 366A) (17)
DESCRIPTION OF EVENT
On February 24,1997, Unit 2 was in Mode 3 following core refueling. It was determined that Technical Specification Surveillance Requirement 4.5.2.c was not met when loose debris was discovered in the Reactor Containment Building. On February 23,1997, Unit 2 entered Mode 4 at 1222 hours0.0141 days <br />0.339 hours <br />0.00202 weeks <br />4.64971e-4 months <br /> and Mode 3 at 1556 hours0.018 days <br />0.432 hours <br />0.00257 weeks <br />5.92058e-4 months <br />.
At 1204 on February 23,1997, an inspection of the Unit 2 Reactor Containment Building was performed prior to entry into Mode 4 to ensure the requirements of Technical Specification Surveillance Requirement 4.5.2.c were met. The surveillance for Technic 41 Specification 4.5.2.c requires the Reactor Containment Building to be free of loose debris which could be transported to the containment sump and cause restriction of the Emergency Core Cooling System pump suctions during a design basis event. During the pre-Mode 4 inspection, maintenance was allowed to remain in progress.
Material associated with each ongoing maintenance activity was to be separately controlled by the plant surveillance procedure for containment inspection. These controls were to be used to verify that no loose debris was left in containment upon completion of the activity.
At 0530 hours0.00613 days <br />0.147 hours <br />8.763227e-4 weeks <br />2.01665e-4 months <br /> on February 24,1997, bags containing three sets of personnel contamination clothing, a few discarded booties and gloves, and a radiological controlled area warning sign were discovered unattended inside the Reactor Containment Building near the auxiliary airlock. The investigation of this occurrence could not determine how or when this material arrived at the auxiliary airlock. The last time that this area was verified free of loose debris was at approximately 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> on February 23,1997. The material was removed from containment at approximately 0700 hours0.0081 days <br />0.194 hours <br />0.00116 weeks <br />2.6635e-4 months <br /> on February 24,1997. Subsequently, a containment inspection for meeting Technical Specification Surveillance Requirement 4.5.2.c was reperformed. A number of additional small items were found and removed. The Nuclear Regulatory Commission was notified at 1840 hours0.0213 days <br />0.511 hours <br />0.00304 weeks <br />7.0012e-4 months <br /> on February 24,1997.
On March 27,1997, Unit 2 was in Mode 3 following a reactor trip. During a reactor containment walk-down following the reactor trip, loose debris was discovered in the reactor containment building. This case involved some lagging found removed and unsecured inside the regenerative heat exchanger room. Additionally a small quantity of loose debris was also present. All of the items discovered were removed or replaced.
Based on the discovery of this debris, five managers performed a detailed walk-down of the Unit 2 reactor containment building. These walk-downs led to the discovery of miscellaneous small items like tape, bits of paper, pens and wire. As a result of these discoveries, additional walk-downs were performed. These walk-downs resulted in the discovery of several other items in the reactor containment building elevator equipment room. All of these items were immediately removed.
A subsequent inspection of the Unit 1 Reactor Containment Building on March 28, 1997, performed in response to the findings in Unit 2, resulted in the discovery ofloose debris inside the elevator equipment room and other locations. These items were removed.
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- - U.S. NUCLEAR REaULATORY COMMISSloN gesi LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET LER NUMBER (6)
PAGE (3)
"MP
%IJE
- a South Texas, Unit 2 05000 499 3
OF 4 97 -- 003 01 l
TEXT (If more space is required, use additional copies ofNdC Form 366A) (17)
CAUSE OF EVENT
The cause of these occurrences was a failure to communicate management's expectation for the control ofloose i
debris in the Reactor Containment Building during restart operations following an outage. All of the items l
l found during these walk-downs are believed to have been left during outage periods. Many of the items were discovered in locations that are not accessible during power operations. A contributing condition to this event l
is the lack of a clear distinction in the surveillance procedure between the acceptance criteria for the Technical j
Specification requirements and the stations housekeeping expectations.
l
ANALYSIS OF EVENT
l l
Failure to meet the requirements of Technical Specifications is reportable pursuant to 10CFR50.73(a)(2)(i)(B).
An evaluation determined that the Emergency Core Cooling System would not have been compromised during a design basis event. A detailed review has determined it is highly unlikely the material found in the bags discovered near the auxiliary airlock could have migrated to the emergency sumps because of the tortuous path i
existing between the two locations. Some of the additional material found during the February 24, 1997 i
Reactor Containment Building reinspection after the discovery of the bags at the auxiliary airlock had the J
potential to reach the emergency sumps. The total potential blockage area of this loose debris that could have l
reached the containment sump was determined to be far less than the blockage area assumed in the calculation i
for ensuring adequate Emergency Core Cooling System pump operation. There were no adverse safety or i
radiological consequences from this event.
Based on evaluations performed, it was determined that the Emergency Core Cooling System would not have i
4 j
been outside its design basis. There is no safety significance associated with the debris found inside j
containment since the Emergency Core Cooling System sumps would not have been affected. Additionally, 1
other system interaction effects of this material on the Fire Hazards Analysis, Post-Design Bases Accident sump l
fluid conditions and prohibited metals inside containment were evaluated and it was determined that there l
would be no significant affect due to this debris. The Emergency Core Cooling System remained capable of performing its design function throughout all of these events. There were no adverse safety or radiological consequences from this event.
The aggregate of the debris discovered did not result in a failure to satisfy the Technical Specification s
l requirements for sump operability; however, they do represent a failure to meet the acceptance criteria of the j
surveillance procedure.
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NRC FORM 306A U.S. NUCLEAR REGULATORY CoMMISSloN 14 951
,e LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION FACILITY NAME (1)
DOCKET LER NUMBER (6)
PAGE (3)
YEAR SEQUENTIAL REYlSION South Texas, Unit 2 05000 499 4
OF 4
9 7 -- 003 01 TEXT (if more space is required, use additional copies of NRC Form 366A) (17)
CORRECTIVE ACTIONS
1.
All discovered loose debris was removed from the Unit 2 Reactor Containment Building.
2.
A reinspection of the Unit 2 Reactor Containment Building and an inspection of the Unit 1 Reactor Containment Building were performed. Additional miscellaneous debris was immediately removed.
3.
Plant Management has directed that all individuals on an entry team be briefed on acceptance criteria required for the control ofloose debris in the Reactor Containment Building in Modes 1,2,3 and 4.
Each team is assigned a Team Leader who is responsible for ensuring compliance with the requirements of Technical Speci6 cations. The Shift Supervisor conducts a formal brienng of all individuals on the entry team. The brienng requirements are part of the surveillance procedure and provide speciSc topics and material to be provided to the entry team. The Reactor Containment Building inspection procedure was revised to include these requirements on April 17,1997.
4.
A process improvement team has been formed to conduct a comprehensive review and improve the Reactor Containment Building control of loose debris to support both outage activities and at-power entries. The corrective actions identified by this team will be implemented prior to the start of 1RE07 on September 13,1997. Some of the items that will be considered to improve the process for outage activities are Supervisor / Foremen brie 6ngs to all entry team members two shifts prior to entry into Mode 4, plant announcements prior to entry into Mode 4, Controlled Access Monitors for Containment entry for some specined time prior to entry into Mode 4, and roving Reactor Containment Building inspectors.
5.
Prior to the implementation of the process improvement team recommendations, any Reactor Containment Building entry in Mode 5 will require either each individual on an entry team to be briefed on acceptance criteria required for the control of loose debris in the Reactor Containment Building in Modes 1,2,3 and 4, or other methods to ensure managements expectations are met.
6.
The procedure used to control loose debris in the containment will be evaluated to ensure the acceptance criteria for Technical Specification surveillance requirements and housekeeping expectations are clearly distinguished. This will be completed by September 13,1997.
ADDITIONAL INFORM ATION:
Unit 1 Licensee Event Report 96-003 was previously submitted by the South Texas Project to the Nuclear Regulatory Commission regarding a failure to meet the requirements of Technical Speci6 cation 4.5.2.c regarding surveillance inspection of containment for loose debris. The causes of that occurrence were an inadequate review of requirements governing the activity and an inadequate pre-job brienng. The Reactor Containment Building inspection procedure was enhanced to clarify how engineering assessments should be used to determine if specinc material meets inspection acceptance criteria. In addition, station wide training was conducted prior to the February 1997 Unit 2 refueling outage regarding the lessons learned from the event.
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