ML20072R165
| ML20072R165 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 03/15/1991 |
| From: | Wallace E TENNESSEE VALLEY AUTHORITY |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9103220229 | |
| Download: ML20072R165 (9) | |
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1.nneuee va%v unora v .11oi une45e$ $7NwAY 15A73555 MAR 151991 U.S. Nuclear Regulatory Commission ATTH: Documer.t Control Desk Washington, D.C. 20555 Gentlement In the Matter of ) Docket Nos. 50-327 Tenni.asee Valley Authority ) 50-328
- SEQUOYAll NUCLEAR PLANT (SQN) UNITS 1 AND 2 - DOCKET NOS 50-327 AND 50-328 - FACILITY OPERATING LICENSES DPR-77 AND DPR SPECIAL REPORT 91-01 Revision 1 - 10 CFR 50, APPENDIX R, IN ACCORDANCE WITl!
LICENSE CONDITION 2.11 The enclosed revised special report providea updated cause of condition, and corrective actions relative to a noncompliance with the requirement of License Conditions 2.0.13.c of the linit. 2 Facility Operating License.
These updates are based upon additional investigation and evaluation committed to by TVA in the special report dated February 7, 1991. The noncompliance condition van originally reported in accordance with Unit 2 License Condition 2.11. The changes from TVA's original response are designated by revision bars.
If you have any questions concerning this submittal, please telephone M. A. Cooper at (615) 843-8422.
Very truly yours, TENNESSEE VALLEY AUTIIORITY yd I J s
/d gt44 o E. G. allaca, Manager Nuclear Licensing and Regulatory Affairs Enclosure cc: See page 2 a 1 9103220229 910315 [ / d
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y4 2, MAR 151991:
. U.S. Nuclear _ Regulatory Comission cc:(Enclosure)t. .
Ms. S.-C. Black, Deputy Director
- Project Directorate 11-4 -!
- U.S. Nuclear Regulatory Comission 10ne White Flint, North. l 11555 Rockville Pike:
-Rockville, Maryland 20852
= Mr. J.- N. Donohew Project M' anager I U.S. Nuclear Regulatory Comission
' One. White Flint, North 11555 Rockville Pika '
RockvillehMaryland 20852 [
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'NRC-Resident Inspector
-Sequoyah Nuclear Plant'
- 2600 Igou Ferry. Road '
Soddy-Daisy, Tennessee :37379
. .Mr. B. . A. Wilson,: Project Chief-
' U.S. Nuclear Regulatory.Comission Region II--
.101 Marietta Street,-WW, Suite =2900 _
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- Atlanta,_ Georgia J30323 s ,.
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. . 9 ENCLOSURE 14-DAY FOLLOW-UP REPORT SPECIAL REPORT 91-01 DESCRIPTION OF CONDITION Condition 1-On January 24, 1991, at 1850 Eastern standard time (EST) with Units 1 and 2 operating in Mode 1 at 100 percent power, Operations was notified that during a post modification walkdown inspection to verify conduit routing dimensions, ,
it was discovered that several Unit 1 and Unit 2 conduits wrapped.with 1-hour fire wrap had been routed in areas that lacked fire suppression and ,
detection. This walkdown was being performed in accordance with Sequoyah Engineering Procedure (SQEP) 67, " Interim Procedure to Control Appendix R Urawings Until a New Drawing Series is Issued," following implementation of Cycle 4 refuelwng outage Appendix R modifications to support accurate plotting i of the conduits on the Appendix R sketch (ARSK) drawings. These conduits contained control circuits to the refueling water storage tank (RWST) and volume-control tank ~(VCT) outlet valves; the outage modifications had been implemented to resolve previously identified Appendix R Interaction 120.
'Further investigation identified four additional conduits associated with the Unit 2 centrifugal charging pumps that had a 'l-hour fire wrap, ~but were routed in an' area that did not:contain fire suppression and detection. These conduits'were previously identified as Interaction 86 (in 'he 1984
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timef rame). Rerouting and wrapping of the conduits had been completed in 1986.
Table 1 Conduits wrapped. in a 1-hour-rated fire barrier, but routed in areas without '
adequate, fire detection and an automatic fire suppression system:
Unitt Interaction Conduit Cable Cable Used For
. =1 120 IV4003A IV4001A Control for 1-LCV-62-135 RWST outlet valve
.'2 '120 2V4006B 2V2774A~ Control for 2-LCV-62-133 VCT outlet-valve 2 120 ~ 2V4012A 2V2764A Control for 2-LCV-62-132 VCT outlet valve 2 120 2V4012A 2V2071A Control for 2-LCV-62-135 RWST outlet valvo 2 86 2PL3003A 2PL3003A Control for centrifugal charging pump (CCP) 2A-A. room cooler 2_ 86 2PL3008A- 2PPSS2A Control for.CCP 2A-A 2 86 2PP550A 2PP550A Supply for CCP 2A-A 2 86 2PL3001A 2PL3001A Supply for CCP 2A-A room cooler r
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Unit 1 and -2 conduit locations are in the auxiliary building. Elevation 690 -
valve gallery mezzanine. . For Unit 1, the column lines are A3 to A4 and T to U. For Unit 2, the column lines are A12 to A13 and T to U.
,As a_ result of.the above-identified deficiencies, Condition Adverse-to Quality
. Report (CAQR) SQP910029 was written. Immediate actions taken included ensuring 1that the areas were being covered by the hourly, roving' fire watch patrois and conducting a walkdown, which determined that no significant levels of combustibles existed in the areas that would challenge the 1-hour-rated i fire barriers. ;
4 Appendix R, Interaction 120, was identified in 1984. Design Change Notices (DCN) M1893A and M03213A were initiated on February 27, 1990, and April 12, 1990; for Unit 1 and Unit 2 respectively. Upon investigation it was determined that the DCN pr oarer did perform a constructibility walkdown but was not aware of the possibility that conduit routing could deviate from design. The reviewers of the DCNs were ascer and familiar with Appendix R but did not perform a field _walkdown. This re as.ted in the DCNs being issued without sufficient routing instructions. During the installation process, the conduits were routed through an area that did not contain fire suppression and detection since there were no routing restrictions specified in.the DCNs for-these conduits. Unit 1 and Unit 2 returned to operation in June- 1990 and '
-November 1990.respectively. Walkdown of Unit 1 conduit IV4003A for updating.
the ARSK' drawings to include actual conduit routing was performed on June:18,'1990.- The conduit. routing was not discovered to be in an area lacking fire detection and suppression since personnel performing the walkdown were'not cognizant-of Appendix R requirements. .During a postinstallation walkdown performed on January 24, 1991, for updating the ARSK drawings of Unit- 2, it- was identified-..that the conduits were routed in an area lacking (
fire detection and' suppression.
inppendix_R, Interaction:86, was identified in 1984. Engineering Change Notice
,(ECN) 6235 was issued in 1985 to reroute and wrap; Appendix _ R conduits. This
-ECN-was~ implemented in l986. -The walkdown _for updating the ARSK. drawings in z
1987 did not' indicate:the conduits had'been routed in an area that lacked fire detection and suppression. Historical information could not be reconstructed ~
- with regard-to personnel qualification in the design and design review; however, it was determined:that there were no restrictions placed in the-ECN .
for-_the ' uting of the conduits.- Further investigation by personnel on
~ January ,-1991, identified _this-deficiency.
Conditis.: 2' -
On_ January 30,1991, at '1540 EST with Units 1 and -2_ at 100 percent power, it was determined during a postmodificatimn walkdown inspection to verify. Units 1 and.2 Cycle 4 modifications that-several conduits-were routed in areas containing fire _ detection and suppression but.were not wrapped with the 1
. required 1-hour-rated fire barrier. These conduits contain power supply circuits to Units 1-and 2 source range neutron. monitor nmit. control room (MCR)-
panels. .These concuits are provided in Table 2.
b Table 2 Conduits routed in an area with adequate fire detection and automatic <
suppression system, but not wrapped in 1-hour-rated fire barrier material Unit 1 Conduit Cable Function 1 MCl289II IPV13111 Vital alternating-current (ae) supply to MCR Panel 1-M-13 (source range neutron monitor) 1 MCl28911 IPV13311 Vital ac supply to MCR Panel 1-M-13 (source range neutron monitor) 1 MC2546II IPV13!II Vital ac supply to MCR Panel 1-M-13 (source range neutron monitor) 1 MC2546II IPV13311 Vital ac supply to MCR Panel 1-M-13 (source range neutron monitor) 2 MC1309II 2PV131I? Vital ac supply to MCR Panel 2-M-13 (source range neutron monitor) 2 MC130911 2PV133II Vital ac supply to MCR Panel 2-M-13 (source range neutron monitor)
The Units 1 and 2 conduits are located on Elevation 714 of the auxiliary building defined by Columns A4 to A8 and Q to R. The affected areas are being covered by the hourly,-roving fire watch patrols.
ECN 6186 was issued to install qualified source and intermediate range neutron monitoring channels and to resolve outstanding Appendix R connitments for the source range channels. Revision 3 of the ECN was issued on November 22, 1989,-
with the Unit 1 Cycle 4 drawings and called for the wrapping of the conduits with 1-hour-rated fire barrier material. The-scope of Workplan (WP) 6186-01 was to install new conduits, amplifiers, and junction boxes as specified by the ECN. The associated drawings had notes requiring the conduits to be wrapped with 1-hour approvad fire barrier material, but did not specify the wrapping material type. / ecision was made to implement the WP even though the type of-wrapping mat- ..a1 was not specified.
.The WP was approved on December- 27, 1989, without including the conduit wrapping requirements. The cognizant modification engineer for the WP had requested verbally that NE specify the 1-hour approved fire barrier material.
The appropriate 1-hour-rated fire barrier material was verbally provided to the cognizant modification engineer by NE rather than issuance of a field design change notice (F-DCN). Additional' designs for this ECN were issued by the Nuclear Engineering (NE) contractor by means of F-DCNs. The cognizant modification engineer assumed that the NE contractor would issue F-DCNs for the material specifications. Therefore, the cognizant modification engineer decided to initi te the WP change once the type of wrapping material had been specified verbally by NE. Additionally, the cognizant modification engineer was a group leader, meaning that the cognizant modification engineer monitored fieldwork on several modifications, which included craft and field engineers.
-This resulted in the cognizant modification engineer being under a heavy workload. The cognizant modification engineer therefore directed a subordinate to initiate a WP change form to include wrapping of the conduits with the verbally specified material. This direction was not clearly
communicated; and as a result, the subordinate engineer did not include all of the affected conduits in the WP change. Four of the seven conduits that required wrapping were included on the WP change. The WP w?s complete on May 20, 1990. After completion of the modification, the system was reviewed by the cognizant engineer to ensure that the requirements of the ECN had been properly implemented. This review did not identify that the conduits had not been wrapped.
CAUSE OF CONDITION Condition 1 The root cause of the condition is a programmatic deficiency in the preparation of design changes that impact Appendix R cables and conduits.
- Formal guidance does not exist for preparing and/or reviewing design changes.
that have potential Appendix R impact. As a result of this lack of formal guidance, training has not been provided to design change preparers and evaluators with respect to Appendix R program requirements, except for on-the-job training. Some preparers of design change packages may not be fully cognizant of 10 CFR 50, Appendix R, program requirements because of this lack of formal instruction and training. Additionally, design change preparers and reviewers we e not fully cognizant of the discipline responsibilities relative to the Sequoyah Appendix R program. The division of discipline responsibility was not defined; and the specific disciplines did not have a full understanding of the specifics of their responsibilities, e.g., ensuring correct routing-of the conduits by putting restrictions in the DCN.
Additionally, an inadequate constructibility review (walkdown) was performed and did not recognize the possibility for field routing of the conduits in an area lacking automatic scopression and detection. This is also considered to have directly resulted from lack of specific program guidance and unfamiliarity of engineering personnel with all the requirements.
Condition 2 The cause.uf this event is that procedures were not followed to request information on the correct material to ensure wrapping of the conduit was implemented. Instead, the individual relied on an-informal process to track
.the design deficiency to resolution. Contributing factors include: (1) the lack of specified-material type in the engineering output documents, (2) the high workload of the cognizant modification engineer (monitoring more than three ECNs at one time and also serving as the group leader), and (3) the coEnizant modification engineer giving inadequate-instructions to a subordinate regarding the WP change.
ANALYSIS OF EVENT The ccnduits listed in Table 1 are wrapped in a 1-hour-rated fire barrier-and l are Incated in an area that does not have adequate detection and automatic suppression as required in 10 CFR 50, Appendix R, Section III.G.2.c. The conduits listed in Table 2 are not wrapped in a 1-hour-rated fire barrier and
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are located in an area that does have adequate detection and automatic l
suppression as required in 10 CFR 50, Appendix R, Section III.G.2.c. This special report is being submitted as required by Unit 2 License Condition 2.H.
There are no plant systems or components considered inoperable or incapable of performing their design functions as a result of the condition described in this report. The affected areas are being covered by the hourly, roving firu watch pttrols. This patrol provides assurance that a fire in this area would be ioentified so that appropriate response actions could be initiated.
Additionally, the subject areas have very low in site combustible loading.
The areas are also regulated by the Sequoyah transient fire load program, which ensures that the area is not arbitrarily used to store combustible material. Based upon walkdowns of the affected areas, preliminary indications
-are that an unmitigated fire would not have suf ficient duration to compromise the existing fire wrap during a worst-case fire.
CORRECTIVE ACTION For immediate corrective action, it was verified that the areas where deficiencies were identified were being covered by the hourly, roving fire watch patrols. These roving fire watches will remain in effect until the corrective actions are complete.
As part of the investigation of this condition, an evaluation and walkdown of rooms and locations in the auxiliary building that are not provided with fire detectors and autoratic fire suppression systems were performed. Two areas were identified with 1-hour wrapped conduits in an area without fire suppression and detection. However, these areas were addressed in previous walkdowns, and an evaluation had been performed documenting the acceptability based on a fire hazard analysis. No additional problems were identified with respect to 1-hour fire rated conduits routed in an area without fire suppression and detection.
The ARSK drawings, which contain the detailed routing of recent conduits pertaining to Appendix R, are currently being updated as a result of recent modifications performed relative to Appendix R. SQEP-67 is the procedure to ensure that the ARSK drawings are maintained to reflect the "as constructed" conditions of Appendix R conduit routing.
The following additional interim controls have been instituted for future design packages involving Appendix R conduits:
- 1. The proposed conduit route shall be walked down before the design issuance
-to verify there is no potential to route through an area that lacks suppression and detection. If a potential exists, appropriate warnings and directions shall be placed on the design change authorization.
- 2. The postmodification walkdowns will now be done as soon as the conduit is supported and before cable pulling activities.
- 3. Other engineering disciplines will coordinate with the Sequoyah Mechanical Engineering group by use of a quality information release to ensure that the conduit will not enter an area that lacks suppression and detection.
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I SQEP-26, Attachment 12. " Technical Evaluation Checklist," has been revised to provide additional questions concerning the routing of wrapped conduits. A lesson plan will be developed and training will be provided to NE personnel and contractor design personnel. This training will include the requirements and discipline responsibilities for the Appendix R program and the need and requirements for constructibility walkdowns for Appendix R designa and will include that the material requirements must be specified in the design output document.
To address the specific conduits identified under Condition 1 (Table 1), TVA will perform an evaluation u.ing Generic Letter 86-10. " Implementation of Fire Protection Requirements," to analyze the acceptability of the configurations.
As a result of Condition 2, an F-DCN was initiated on February 6,1991, to specify the required wrapping material. A WP was written and approved on February 12, 1991, to wrap the conduits. The conduits identified in Table 2 will be wrapped by May 3, 1991.
Walkdowns for Cycle 4 refueling outage modifications were completed and reviewed to verify that conduits requiring wrapping were in fact wrapped. No additional problems were identified.
Discussions with modification engineers on the importance of initiation of F-DCNs when infocmation contained in a design change output document is not adequate was completed on February ~ 25, 1991. This will ensure that questions and open items associated with the design are tracked to full implementation.
To address the high workload of the cognizant modification engineer (being a group leader and having to monitor fieldwork on modifications), a new concept was implemented during the Unit 2 Cycle 4 refueling outage. This concept assigns a field engineer to each craft crew and allows the group leaders to monitor the activities of only the field engineers. This concept was successfully implemented during the Unit 2 Cycle 4 refueling outage. No specific action is being taken rclative to the involved individuals in Modifications because they are no longer employed at Sequoyah. Based on completeness reviews of the majority of the Unit 1 Cycle 4 modifications, there is no indication.that the high workload resulted in other partially implemented modifications.
ADDITIONAL INFORMATION A review of special reports on Appendix R was performed for commonalities relative to root cause. No commonalities were discovered between the special reports, although program documentation weaknesses with respect to specific portions of the Appendix R program were identified during an in-house Nuclear Quality Assurance audit performed November 5-29, 1990.
Licensee Event Report (LER) 50-327/90013 dealt with the main control room fire detectors being rendered inoperable as a result of an inadequate design review. A contributing cause to the LER was considered to be a misunderstanding among NE discipline organizations regarding fire protection
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program responsibilities, i.e., heating, ventilation and air conditioning, fire protection. and Appendix R-issues-were handled by different engineering groups and no single group took ownership of this particular issue.
Corrective action was performed as a result of the LER to define the responsibilities of each organization. The completion of the corrective action occurred on July 27, 1990, and after the DCNs involving Condition 1
.were issued.
COMMITMENTS
- 1. TVA will develop a lesson plan and provide training to TVA NE personnel and contractor design personnel on Appendix R preparation and design review by June 7, 1991.
- 2. TVA will perform a Generic Letter 86-10 analysis of Appendix R deficiencies for conduits in Table 1 to evaluate acceptability by August 16, 1991.
- 3. TVA will wrap the conduits identified in Table 2 by May 3, 1991, 1
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