05000271/LER-1998-001, :on 980124,discovered That Penetration Seal Did Not Conform to Tested Configuration for 3-h Rated Seal. Caused by Lack of Formal Fire Protection Program at Time of Seal Installation.Repaired non-conforming Seal
| ML20247G904 | |
| Person / Time | |
|---|---|
| Site: | Vermont Yankee File:NorthStar Vermont Yankee icon.png |
| Issue date: | 05/14/1998 |
| From: | Maret G VERMONT YANKEE NUCLEAR POWER CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| BVY-98-75, LER-98-001, LER-98-1, NUDOCS 9805210006 | |
| Download: ML20247G904 (5) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(1) 10 CFR 50.73(a)(2) 10 CFR 50.73(a)(2)(ii) 10 CFR 50.73(a)(2)(x) 10 CFR 50.73(a)(2)(v), Loss of Safety Function 10 CFR 50.73(a)(2)(vii), Common Cause Inoperability |
| 2711998001R00 - NRC Website | |
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VERMONT YANKEE NUCLEAR POWER CORPORATION r7 P.O. Box 157, Govemor Hunt Road
(\\n/y Vernon, vermont 05354-0157 V '-'
(802) 257-7711 May 14,1998 BVY 98-75 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington D.C. 20555
Subject:
Vermont Yankee Nuclear Power Station License No. DP.R-28 (Docket No. 50-271)
Reportable Occurrence No. LER 98-001, Rev.1 As defined by 10CFR50.73, we are reporting the attached Reportable Occurrence as LER 98-001, Rev.1.
I Sincerely, I
ION %. FEE Nt' CLEAR POWER CORPORATION VE A
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m RF regog 4. faret Plant Manager
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l cc:
USNRC Region I Administrator
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USNRC Resident Inspector-VYNPS USNRC Project Manager-VYNPS VT Dept. of Public Service M
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, y J... "I 9905210006 990514 9
[DR ADOCK 05000271 l
PDR y
NRC Form 366 U.S. NUCLEAR REGULATORY COMMIS$10N APPROVED BY OMS NO. 3150-0104 (4-95)
EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY j
INFORMATION COLLECTION REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED LICENSEE EVENT REPORT (LER)
ARE INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (T-6 F33), U.S. NUCLEAR REGULATORY COMMIS$10N, WASHINGTON, DC 20555 0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.
FACILITY NAfE (1)
VERMONT YANKEE NUCLEAR POWER STATION DOCKET IRsWER (2)
PAGE (3) 05000271 01 0F 04 TITLE (4) A TECHNICAL SPECIFICATION FIRE BARRIER PENETRATION SEAL WAS DETERMINED TO BE IN A CONDITION WHICH LOWERED l
THE RATING OF THE AFFECTED FIRE BARRIER... ROOT CAUSE UNKNOWN EVENT DATE (5)
LER IR5WER (6)
K PORT DATE (7)
OTER FACILITIES INVOLVED (8)
MONTH DAY YEAR YEAR SEQUENTIAL REVISION MONTH DAY YEAR FACILITY NAME DOCKET NO.(S)
NUMBER NUMBER 05000 01 24 98 98 01 01 05 14 98 N/A OPERATING TNIS REPORT IS SUBMITTED PURSUANT TO THE REGUIREENTS OF 10 CFR 5: CNECK ONE OR MORE (11) le3E (9)
N 20.2201(b) 20.2203(a)(2)(v)
X 50.73(a)(2)(1) 50.73(a)(2)(vill)
POWER 20.2203(a)(1) 20.2203(a)(3)(1) 50.73(a)(2)(ii) 50.73(a)(2)(x)
LEVEL (10) 97 20.2203(a)(2)(l) 20.2203(a)(3)(i()
50.73(a)(2)(Ii()
73.71 20.2203(a)(2)(ll) 20.2203(a)(4) 50.73(a)(2)(IV)
OTHER 20.2203(a)(2)(iii) 50.36(c)(1) 50.73(a)(2)(v)
(Specify in Abstract beloW or in NRC 20.2203(a)(2)(iv) 50.36(c)(2) 50.73(a)(2)(vii)
Form 366A) l LICENSEE CONTACT FOR THIS LER (12)
NAME TELEPHONE NO. (include Area Code)
GREGORY A. MARET, PLANT MANAGER 802-257-771t CWFLETE ONE LINE FOR EACM (XBN'ONENT FAILURE DESCRIBED IN THIS REPORT (13)
CAUSE
SYSTEM COMPONENT MANUFACTURER REPORTABLE
CAUSE
SYSTEM COMPONENT MANUFACTURER REPORTA3LE TO EPIX TO NPRDS NA NO NA NA NA SUPPLEMENTAL REPORT EXPECTED (14)
EXPECTED M0 DAY YEAR SUBMISSION YES X
NO DATE (15)
(If yes, complete EXPECTED SUBMIS$10N DATE) g ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) (16)
On 01/24/98, while performing a post work inspection of a fire barrier penetration seal subject to Vermont Yankee plant T4chnical Specifications (TS) following work potentially affecting the seal, it was discovered that the penetration seal did not conform to the tested configuration for a 3-hour rated seal. A compensatory fire watch was established as required by plant l
TS, End the seal was repaired. The cause investigation could not determine the root cause for the failure to construct the seal l
per the specifications. The non-conforming aspect of the seal had not been disturbed since initial plant construction. The I
curr:nt VY Fire Protection Program and configuration management processes would not aslow the installation of a non-conforming seat. Long term corrective actions to identify and correct similar conditions include: 1) inspections of similar seals, l
- 2) intrusive examination of a sample of seals,3) expanding the intrusive inspection sample if needed, and 4) repairing any j
inIdiquate seals. Although the seal did not meet the requirements for a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rating it would have challenged propagation of a
)
fire. The combination of automatic fire suppression and detection, an on-site fire brigade and the as-built condition of the fire barri r seal gives confidence that a postulated fire would have been rapidly detected, and extinguished such that plant safe i
shutdown capability would not have been jeopardized. This is consistent with the intent of the fire protection program at VY.
Thersfore it is concluded that this event posed no significant increase in risk to either the health or safety of the public.
NRC Form 366 (4-95)
NRC Fcre 366 U.S. NUCLEAR REGULATORY COMIS$10N APPROVED BY OMB NO. 3150-0104 (4-95)
EXPIRES 04/30/96 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATION COLLECT!DN REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED LICENSEE EVENT REPWT (LER)
ARE INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY. FORWARD COMENTS REGARDING BURDEN EST! MATE TO THE
!NFORMATION AND RECORDS MANAGEMENT BRANCH (T-6 F33), U.S. NUCLEAR REGULATORY COMNIS$10N, WASHINGTON, DC 20555-0001, AND TO ThE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.
FACILITY NRfE (1)
DOCKET IRBGER (2)
LER 1RBGER (6)
PAE (3)
YEAR SEQUENTIAL NUMBER REV #
VERMONT YANKEE NU" LEAR POWER CORPORATION 05000271 96 01 01 02 0F 04 TEXT (If more space is required, use additional coples of NRC Form 366A) (17)
DESCRIPTION OF EVENT
On 01/24/98, while operating at 97 percent of rated power, during the performance of a post work inspection of a fire barrier penetration seal subject to Vermont Yankee plant Technical Specifications (TS) following work potentially affecting the seal, it wts discovered that the penetration seal did not conform to the tested configuration for a 3-hour rated seal. The fire barrier wts between a 4160 volt switchgear room in the control building (Ells =NA) and a hallway connecting the turbine building (Ells =NM) and the radweste building (Ells =NE). The major non-conformance was discovered by the VY Fire Protection Engineer as he was assessing minor degradation caused by work done in a cable tray penetrating a rated fire barrier. The movement of cable tray covers during the work effort resulted in minor cracking in the grout seal around the tray. The work crsw contacted the Fire Protection Engineer (FPE) to have the minor flaw assessed. Upon inspection, the FPE confirmed that the damage caused by the work effort was minor. However, the FPE noted a gap which had been created as the cable tray covsr had been flexed during the work effort. While investigating the gap, the FPE discovered the gap to penetrate deeply into the wall. The FPE requested that the seal be excavated to ensure that the seal, absent any disturbance caused by the cable tray work, conformed to the rated configuration. The excavation revealed that the seal had not been properly constructed, and that a major void had been left during the seal's original installation. The volume of the void was sufficient for the FPE to conclude that it did not meet the requirements for a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rated fire barrier seal penetration as required by plant TS. A compensatory fire watch was established as required by plant TS, and the seal was repaired, CAUSES OF EVENT The cause investigation could not determine the root cause for the failure to construct the seal according to the specifications for a 3-hour fire seal.
l The apparent cause for this event was the lack of a formal fire protection program at the time of the sealinstallation.
ANALYSIS OF EVENT
The Fire Protection Program at Vermont Yankee uses a defense-in-depth concept to achieve a high degree of fire safety.
The objective of the defense in depth is to:
1.
Reduce the potential of fires starting, 2.
Rapidly detect, control, and promptly extinguish those fires that do occur, 3.
Provide adequate protection for structures, systems, and components so that a fire will not prevent the safe shutdown of the plant, and prevent the release of a significant amount of radioactive material, when fires occur.
The fire barrier penetration seal described in this report supports objective number 3 of the Fire Protection Program through conformance to the VY Fire Protection System design bases. VY System Design Bases are divided into two categories, Safety DIsign Bases and Power Generation Design Bases.
Saftty Design Basis - The safety design basis for a safety system states in functional terms the unique design requirements which establish the limits within which the safety objective shall be met.
A safety objective describes in fuctiorni terms the purpose of a system or component as it relates to conditions considered to be of p.imary significance to the protection of the public. This relationship is stated in terms of radioactive material barriers or radioactive material release. VY Fire Protection Systems have no Safety Design Bases.
The systems are not credited for protection of the public but provide protection for plant equipment in support of continued operation and are therefore assigned Power Generation Design Bases.
NRC Form 366 (4-95)
NRC Form 366 U.S. NUCLEAR REGULATO;tY EOMMISSICW APPROYED BY OMB NO. 3150 0104 (4 95)
EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATION COLLECTION REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED LICENSEE EVENT REPORT (LER)
ARE INCORPORATED INTO THE LICENSING PROCESS AND FED BACK TO INDUSTRY. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (T-6 F33), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150-0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.
FACILITY NAME (1)
DOCKET NLmsER (2)
LER 1RMBER (6)
PAGE (3)
YEAR SEQUENTIAL NUMBER REV #
YERMONT YANKEE NUCLEAR POWER CORPORATION 05000271 98 01 01 03 OF 04 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
Powsr Generation Design Basis The power generation design basis for a power generation system states in functional terms the unique design requirements which establish the limits within which the power generation objective shall be met. Power Gsneration Design Bases of the VY Fire Protection Systems are listed below.
The Fire Protection System shall prevent propagation of fire and isolate the areas of the fire by:
1.
Providing a rehable supply of fresh water for fire fighting purposes.
2.
Providing a reliable system for delivery of the water to potential fire locations.
3.
Providing automatic fire detection in those areas where the danger of fire is more pronounced.
4 Providing fire extinguishment by fixed equipment activated automatically or manually in those areas where danger of fire is most pronounced.
5.
Providing manually operated fire extinguishing equipment for use by station personnel at selected locations.
6.
Providing means to isolate areas so that fires are prevented from propagating from one area to another.
As previously mentioned, the VY Fire Protection Program is a defense-in-depth approach. Similarly the systems employed by VY in support of the system design bases provide defenso-in-depth against propagation of a fire. The fire barrier seal found in the non-conforming condition challenged achievement of the Fire Protection System design basis number 6 (listed above).
However the other layers of protection afforded by the chosen approach mitigated the significance of that non-conforming seal.
10CFR50 Appendix R states that when "considering the effects of fire, those systems associated with achieving and maintaining safe shutdown conditions assume major importance to safety because damage to them can lead to core damage resulting from loss of coolant through boiloff." The seal is credited in VY's Safe Shutdown Capabilities Analysis in demonstrating that the 10CFR50 APP R requirements are met, and that those systems associated with achieving and maintaining safe shutdown conditions are available in the event of a fire affecting either the west switchgear room or the radwaste building hallway.
Although the seal did not meet the requirements for a 3 hour3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> rating, it would have challenged propagation of a fire, as described in the plant TS bases. The combination of automatic fire suppression and detection, en on-site fire brigade and the as-built condition of the fire barrier seal gives confidence that a postulated fire would have been rapidly detected, and extinguished such that plant safe shutdown capability would not have been jeopardized. This is consistent with the intent of both the fire protection program and the 10CFR50 Appendix R program at VY. Therefore it is concluded that this event posed no significant increase in risk to either the health or safety of the public.
CORRECTIVE ACTIONS
Immediate Actions:
1.
An Event Report was initiated to document this event and initiate a root cause analysis to determine the cause and appropriate corrective actions for this event. The expected completion date is 03/13/98.
2.
The non-conforming seal was repaired. This action is complete.
NRC Form 366 (4-95)
a NRC Fcra 366 U.S. NUCLEAR REGULATORY COMMIS$10N APPROVED BY OMB NO. 3150-0104 (4-95)
EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORY INFORMATION COLLECTION REQUEST: 50.0 HRS. REPORTED LESSONS LEARNED LICENSEE EVENT REPORT (LER)
ARE INCORPORATED INTO THE LICENSING PROCESS AND FCD BACK TO INDUSTRY. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE INFORMATION AND RECORDS MANAGEMENT BRANCH (T 6 F33), U.S. NUCLEAR RFGULATORY COMMIS$10N, WASHINGTON, DC 20555-0001, AND TO THE PAPERWORK REDUCTION PROJECT (3150 0104), OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503.
FACILITY NAfE (1)
DOCKET IRaeER (2)
LER 1R55ER (6)
PAGE (3)
YEAR SEQUENTIAL NUMBER REV #
VERMONT YANKEE NUCLEAR POWER CORPORATION 05000271 98 01 01 04 0F 04 TEXT (If more space is required, use additional copies of NRC Form 366A) (17)
Lona Term Actions:
Bectuse this condition was created during initial plant construction it can not recur. Current VY configuration management control processes and the current VY Fire Protection program would not allow a new sealinstallation which did not conform to the specifications established for a rated fire seal.
l V4rmont Yankee's Project Engineering Department will establish an action plan to determine if additional grout blockouts with similtr problems exist. The expected completion date is 11/30/98. The preliminary action plan is:
1.
Determine the number of similar seals (grout blockouts) which have been undisturbed since initial plant construction.
2.
Visually inspect any seals identified in action number one above.
3.
Perform a destructive examination of a random sample of the seals identified in action number one above.
4 Repair any grout blockouts found to be in non-conformance with their fire rating requirements.
5.
Evaluate the need to repair grout seals based upon the results of the aforementioned inspections.
ADDITIONAL INFORMATION
V1rmont Yankee currently has a rigorous sealinspection program. There are in excess of 1800 fire barrier penetration seals l
subject to the VY fire sealinspection program. VY considers the identified deficiencies to be indicative of the recently improved inspection processes and techniques, and the additional resources recently committed to the fire protection program.
l ThIre have been 5 similar events reported over the past five years:
LER 93-01 Degraded vital fire barriers due to inadequate documentation of assumptions and inadequate procedures, j
LER 94-18 Two vital fire barriers inoperable due to degraded fire penetration seals.
LER 95-04 incomplete repair of inoperable vital fire barrier penetration fire seal.
LER 96-07 Vital fire dampers not installed in accordance with manufacturers instructions.
LER 96-26 Inadequate design implementation and subsequent inadequate documentation of inspection findings result in operation outside of plant design basis for fire mitigstion and Tech. Spec. non-compliance.
NRC Form 366 (4-95)