IR 05000457/1997021
| ML20202F245 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 02/11/1998 |
| From: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | |
| Shared Package | |
| ML20202F193 | List: |
| References | |
| 50-457-97-21, NUDOCS 9802190159 | |
| Download: ML20202F245 (16) | |
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U.S. NUCLEAR REGULATORY COMMISSION REGION 811 Docket No: 50-457
- License W NPF-77 Report No: 50-457/97021(DRS)- -
Licensee: Commonwealth Edison Company
- Facility: ' Braldwood No . lear Power Station Unit 2 Location: R.R. #1, Box 84 l_ Braceville,IL 60407 l
Dat, 3: November 12-21,1997 and January 15,1998 Inspectors: D. Jones, Reactor Engineer -
J. Ellis, Reactor Engineer M. Holmberg, Reactor Engineer -
Approved by: J. A. Gavula, Chief :-
Engineering Specialists Branch 1 Division of Reactor Safety
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9002190159 990211 PDR ADOCK 05000457 G PDR
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I EXECUTIVE SUMMARY
l Braldwood Nuclear Power Plant, Unit 2 NRC Inspection Report 50-457/97021 This nonroutine inspection included a review of the events, assessments, and corrective actions associated with the hydraulic transient (waterhammer) event which occurred in the Unit 2 feedwater system on November 10,199 Ooerations (O21)
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Operations staff initiated timely and appropriate actions in response to the feedwater system waterhammer even .
The fill and vent procedure for the feedwater syttem was inadequate, in that it caused the water hammer event. and is considered a violation of 10 CFR 50, Appendix B, Criterion .
Two additional violations of 10 CFR 50 Appendix B, Criterion V, were identified wnere existing procedures were not followed pertaining to the procedure change process for an inadequate startup procedure, and the problem identification process for a tempering line snubber considered inoperabl Engineering M2.1\
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The licensee's event investigation and assessment effectively determined the sequence of e"ents and cause of the waterhammer even .
Appropriate engineering evaluations hac been implemented for components affected by the waterhammer even .
An additional example of a violation of 10 CFR 50, Appendix B, Criterion V, was identified pertcining to the failure to follow the problem identification process procedure and initiate a PlF on damaged feedwater line snubbers, when the damage was discovere .
Licensee short and long term corrective actions appeared to be adequate to establish the integrity of the affected systems and prevent recurrence of this waterhammer even .
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.c Reoort Detaljs 1. Operations 02 Operational Status of Facilities and Equipment O2.1 Unit 2 Waterhammer Event insoection Scoce (93702)
On November 10,1997, a hydraulic transient (waterhammer) occurred in the Unit 2 steam generator (SG) D feed system. The team reviewed relevant plant drawings, operating and maintenance procedures, plant logs, recorded system parameters and performed system walkdowns to independently verify and assess licensee actions associated with this even + Obcervations and Findinas Pre-Event. Inadeouate Feedwafer Svstem Fill and Vant During the recent Unit 2 Refuel Outage (A2R06), licensee personnel removed the i condensate and Teedwater systems from service to perform maintenance using out of
Snutoff Valve (2FWOO6D) and the Feedwater isolation Valve (2FWOO9D) was isolated and drained to allow work to be performed on the Feedwater Chec.k Valve (2FWO79D).
Feed system wc,rk was ampleted and the feedwater OOS cleared on October 27,199 Subsequently, the licensee completed a fill and vent of the Unit 2 feedwater system using proccdure BwOP FW-3 on or about November 6,1997. However, as discussed below, this procedure did not adequately refill the Unit 2 feedwater system, t
Procedure BwOP FW-3 did not contain instructions to adequately 'i'l sections of the 16 inch diameter feedwater piping between 2FW006D and 2FWOO9D (this piping run is in excess of 100 feet long). This procedure specified a fill of this pipt section without establishing a flow path to vent trapped air. Tne licensee root cauce team draft report stated, "The feedwater venting procedure (BwOP FW-3 rev. 6) does not provide adequate instructions to compress the trapped air while monitoring the feedwater and steam generator pressure to ensure that the trapped air is flushed to the steam generator." Inspectors estimated that the volume of voided piping in the Unit 2 feedwater system equated to 50 feet of 16 inch diameter main feedwater piping, based on the tempering bypass line flow data recorded during the waterhammer event. The licensee's root cause team determined that this voided section of piping sub'equently >
caused a waterhammer in the 2D feedwater system that damaged safety-related equipment on November 10,1997. The licensee's failure to provide an adequate Unit 2D feedwater system fill and vent procedure of a type appropriate to the circumstances, is a violation of 10 CFR 50, Appendix B, Criterion V (VIO
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50-457/97021-01(DRS)). This problem did not exist for Unit 1, as procedure BwOP FW-3 directs the opening of high point vent valves (which did not exist on Unit 2) to fill this section of feedwater pipin Waterhammer Event and Ooerator Actions l On November 10,1997, the licensee completed the Unh 2 plant startup procedure f
2BwGP 100-2 up through step F.14.h. At this step, the plant was in Mode 3 at normal operating temperature and pressure. With the main feedwater supply isolation valves ,
closed, feedwater flow had been established at 32 gallons per minute (gpm) to each SG via the tempering line valves 2FWO34A-D and 2FWC35A-D. Step F.14.h required a trip of the Reactor Trip Breakers as part of a pre-criticality test. This trip generated a P4 signal that initiated a feedwater isolation, which closed feedwater valves: 2FWO34A-D, 2FWO35A-D, 2FWO39A-D, 2FWO43A-D, 2FWOO9A-D, 2FWO510 (-520, -530, -540), and 2FW540A (-520A, -530A, -540A) as designed. At this point in the procedure, all feedwater flow to the SGs was isolate Operators then completed step F.14.1, which reset the feedwater isolation signal, and allowed valves 2FWO34A-D to reopen with their control valve switci,es in the AUTO position. At this point, the automatic flow controller for these valves c.aused valvas 2FWO34A-D to fully open, since there was no flow in the tempering line (e.g. valves 2FWO35A-D remained closed following resetting of the P-4 isolation signal). To restore feedwater flew to all four SGs, the operaters opened valves 2FWO35A-D. Although, opening of these valves was required to maintain feedwater flow to the SGs, no procedure step existed to direct the operators to reopen these valves. Additionally, inspectors identified that a proceudre change had not been initiated to correct this section of the procedure co.itrary tc c3wAP 100-20," Procedure Use and Adherence,"
Revision 7E1, BwAP 100-20, paragraph D.9 required "When an individual perceives that any procedure cannot be performed as writtcn.... " paragraph D.9 c.2 required
" Initiating a permanent or temporary change, .." and paragraph D.9.c.3 required
"!nitiating BwAP 100-20T1 to document any deviations from a procedure." Failure of licensee personnel to follow BwAP 100-20 and issue a procedure revision or change for this inadequate section of procedure 2BwGP 100-2 is a violation of 10 CFR 50, Appendix B, Criterion V (VIO 50-457/97021-02(DRS)).
Just prior to step F.14.J, a note stated " Mechanical binding of the 2FWO39A-D valves has occurred in the past. The intent of step F.14.]is to stroke the valves to provide assurance of their operability." The completion of Step F.14.) of 2BwGP 100-2, required operators to " STROKE 2FWO39A, B, C, D, Preheater Bypass Valves" and step
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F.14.k required " Verify /OPEN 2FWO39A, B, C, D, Praheater Bypass Valves." Operators performed these steps and valves 2FWO39B and 2FWO39C opened. However, vs.lves 2FWO39A and 2FWO39D did not open. Licensee personnel reportedly had assumed (due to the procedure note) that these valves had failed to open due to mechanical binding (later review of data indicated that a 1000 pounds per square inch differential pressure had existed across gate valve 2FWO39D). The licensee staff increased air pressure to the 2FWO39D valve operator to open the valve. After opening this valve,
" banging" sounds were heard by personnel at the valve and in the control room (the
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l initial waterhammer event). Opening 2FWO39D also created a high flow demand /high .
differential pressure condition, across valve 2FWO34D, which caused the valve stem to
! separate from the disc and block a',1 forward feed flow into the tempering line from the i feed system (see section E2.1.b.3.4).
l In response to the waterhammer event, the operators closed valve 2FWO39D, which ended the transient event. Due to the failure of valve 2FWO34D, operators were unable to immediately restore tempering line flow to SG 2D, Operators recognized the loss of tempering line subcooling, and entered procedure 2BwOA SEC-6," Loss of Feedwater Tempering Line Subcooling Unit 2." Using this procedure operators reestablished SG 2D tempering line subcooling using mi auxiliary feedwater pump (within approximately five minutes). Based on review of these events, inspectors considered the recovery actions taken by the operators to be appropriate and timel ,
b.3 Ooerability Process Not Followed for Damaaed Comoonents The independent Safety Engineering Group (ISEG) had identified in audit repert QAS 20-97-009, issued September 4,1997, two instances where the Shift Manager / Engineer
- ad failed to document equipment operability status in a problem identification form (PIF). The corrective actions completed on October 19,1997, for this audit finding included providing written guidance to the Shift Manger / Engineer on how to Gil out this section of the PlF form. Inspectors considered the written guidance provided to the Shift Manager / Engineer appropriately aetailed. A second corrective action still open at the time of this inspection, included discussion of expectations for the " equipment operable" determination in the PlF form. This corrective action was scheduled to be completed at the next shift managers meeting following the refueling outage. Inspectors identified that, corrective action guidance had not yet been effectively implemented, as evidenced by the repeat examples where the Shift Manager / Engineer had failed to document equipment operability status in the FIFs discussed talow. Specifically, the N/A t ' -k status was inappropriate as it constituted an indeterminate state of operability f equipment and systems identified in these PIF .
For PlF A1997-05010 "2D FW Line Water Hammer" issued November 10,1997, the equipment operable section of the PlF had been marhd N!A, vica yes or n .
For PlF A1997-05055 " Supports Damaged Due to System Transient" issued on November 12,1997, the equipment operable section of the PlF had been marked N/A, vice yes or n . For PlF A1997-05074 " Snubbers 2FWO5011S,2cWO5013S, & 2FWO5022S Suspect" issued on November 13,1997, the equipment operable section of the PIF had been marked N/A, vice the yes or n . For PlF A1997-5090 " Flat Spot Indication Identified on Line 2FW87CD-6" issued on November 14,1997, the equipment operable section of the PlF had been marked N/A, vice the yes or no.
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The licensee schedule for corrective actions from the previous audit finding in this area was not aggressive nnd nonconformances with operability process procedures (NSWP-A 15 " Comed Nuclear Division Integrated Repo-ting orogram" and BwAP 330-10
" Operability Determinations") were still occurring as evidenced by the examples discussed above. Thus, the inspectors considered the lack of an aggressive schedule for corrective act:on and the repoat examples of failure to follow existing procedures, to illustrated a licensee staff tolerance for continued procedure nonconformance in this area. Since, the licensee corrective action to discuss expectations with shift managers on this issue had not been completed at the time of these findings, the inspector could not evaluate the effectiveness of this corrective action M preventing recurrence of this proble On November 10,1997, at 1:15 pm and 2:38 p.m., operabrs recorded in the station operator log that the Technical Specification limited condition for operation action requirement 7.8.1a had been entered for the 2D feedwater tempering line snubber, which indicated t"at the licensee had :onsidered the snubber inoperable. However, the licensee had not issued a PIF for this inoperable tempering line snubber. Failure of the Shift Manager / Engineer to fcl low NSWP-A-15 and BwAP 330-10 requirements to issue a PIF for the tempering line snubber considered inoperable is an example of a violation of 10 CFR 50, Appendix B, Critericn V (VIO 50-457/97021-03(a)(DRS)). Conclusions The inspectors considered the operator actions taken in response to the 2D feedwater system waterhammer event to be appropriate and timel The licensee's root cause team attributed the 2D feedwater system hydraulic transient (waterhammer event) to an inadeouate Unit 2 feedwater system fill and vent procedur Failure to provide an adequate Unit 2D feedwaur vent and fill procedure of a type appropriate to the circumstances, is an example of a violation of 10 CFR 50, Appendix B, Criterion The inspectors identified lapses in the licensee's implementation of, or adheience to, the procedure change process or problem identification process as exemplified by the following:
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Licensee personnel failed to follow the procedure change i rocess for an inadequate section of the plant startup procedure, which is an example of a violation of 10 CFR 50, Appendix B, Criterion .
The licensee had failed to initiate a PIF for the tempering line snubber considered inoperable following th.s water Sammer event, which is an example of a violation of 10 CFR 50 Appendix B, Criterion An ISEG audit conductod in September had identified examples of failure to document
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the operability status of compons.nts and systems in a PIF. One licensee corrective 1 action was still open on this issue; however, inspectors identified four repeat examples
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of the same problem, indicating that licensee corrective actions had not yet been effectively implemented. The inspector considered these examples to illustrate e tolerance by the licensee for continued staff nonconformance with procedures governing the documentation of the operab>.ty status of equ!pmen ,
IlLEngineering
, E.? Engineer:ng Support of Facilities and Equipment E Waterhamn)gr Event - Damage. Eyaluations nnd CmtectiYE.AQ1iODS insoection Scoce (92Z20)
i inspectors reviewed information documenting component damage, investigations, corret,:ive actions and licensee engineering evaluations for the 2D ieeowater system waterhammer event which occurred on November 10,199 Observations ar"1 Findings Effective investiga. tion and Event Assessmerit The licensee implemented guidance established in the Electric Power Research Institute (EPRI)" Water Hammer Manual" to diagnose the November 10,1997, 20 feedwater waterhammer event. Inspectors noted that the EPRI guidance and methodology used was consistent with that established in NUREG/CR-5220 " Diagnosis of Condensatien-Induced Waturhammer."
The licensee's assessment of this event was consistent with temperature, pressure and flowrates rnonitored and recorded by the process computer in the feedwater system during the event. The licensee root cause team established tha sequence of events and assessment of this waterhammer event in the Draft Root Cause Team Investigation Report. The following summarizes excerpts from the waterhammer event documented in this repor '
The event occurredi with the plant in Mnde 3, while the SG D secondary side pressure was at normal operating pressure of 1092 pounds pet square inch gauge (psig) and temperature of 557 degrees Fahrenheit (of). Feedwater flow (at 32 gpm and 80 of) had been established via the tempering line, using the discharge pressure from the
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feedwater pump. Immediately prior to opening the preheater bypass valve (2FWO39D)
the dounstream feedwater piping was incompletely filled (See 02.1.b.1) and downstream pressure was at 100 psig. Immediately following opening of velve 2FWO39D, abrupt banging sounds were heard at the valve. The licensee concluded that when 2FWO39D was opened, the tempering li7e pressure dropped and the water volume in the tempering line drained into the unfilled section of feedwater piping. Hot SG water was drawn into the temperir.g line (at reduced pressure) which flashed to steam. This was followed by a collapse of the steam which was surrounded by 80 of
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.,g water (waterhammer). Consequently, the EPRI watotaammer mechanisms which the licensee considered applicable were water-steam counterflow (EPRI Mechanism No. 2)
and steam pocket collapse (EPRI Mechanism No. 3). After about 10-15 seconds with
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2FWO39D open, an additior.al noise was heard and 2FWO39D was closed stopping the transient. The licensee conc!uded that theso observations indicated a second group of waterhammers about 10-15 seconos following the initial event, caused by additional steam entering the line and again being collapsed by surrounding cold wate Adding to the above scenario, was the failure of the tempering flow control valve, 2FWO34D, which shut off flow through th3 tempering line. The failure of this valve (discussed 'n E2.1.b.3.4) caused an additional reduction M pressure in the tempering line during this even b.2 Anptogfale Evaluations Imolemented for @cted SvalemmLCompsnents The licensee concluded that this condensate induced waterhammer event created water slugs that caused localized damar in the proximity of the !mpact or " bang." Basec' on
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the observed damage (described : , .,ection E2.1 b.3) the licensee concluded that the bang (s) occurred in the feedwater tempering line near SG D, with the apparent highest magnitudo, at the top of the 17-feet long vertical riser, upstr9am of the damaged spring can (2FWO9002C).
Initially, the engincering staff completed a piping analysis based on the assumption that l three of the damaged pipe supports on the tempering line were not in place. This analysis confkmed that the line was operable"(e.g. within the American Society of l
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Mechanical Engineers Code, Section ill, Appendix F stress limits). This analysis cupported operatico of the affected tempering line until the damaged supports were [
repaired. The licensee subsequently initiated a piping analysis (in draft form at the conclusion of this inspection) of the tempering line stress levels induced during the waternammer event based on displacements observed near damage suppons. This analysis indicated that the highest stress levels during the wahrhammen event would have occurred near the steam generator nozzle and at the containment penetratio The licensee had completed nondestructive examinations with acceptable results at both of these locations. Further, the licensee had conducted nondestructive examination (magnetic particle testing and ultrasonic testing) of approximately 75 e
percent of the affected feedwater tempering line (2FW87CD-S) wolds with satisfactory results. Ir.cpectors considered these analysis and investigations adequate to establish confidence in the tempering line integrity and operabilit The licensee performed functional testing, engineering evaluation andMr ultrascnic testing to establish confidence in the integrity of the fol!owing valves potentially affected by the waterhammer event: 2 FWO33D, 2FWO35D, 2FWO36 D, 2FWO39D, 2FWO79D, 2AF014A-H. Inspectors considered the evaluations performed adequate to establish confidence in the integrity of these valve .- .. .
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The licensee performed calibration checks of the 2D feedwater loop instrumentation subjected to the transient and the instrumentation was found to be acceptable. The SG ,
level instruments were not calibration checked; however, the licensee considered the instrumentation acceptable based on comparisons and agreement between the different level channels, D.arnaced Eguloment and Corrective Actions The licensee performed system walkdowns of the 20 feedwater system, auxiliary feedwater system and chemical feed system to assess the scope of damage. The damaged equipment identified in these walkdowns and corrected by the licensee is d'scussed in the "ollowing sections. During the root cause investigation, it was discovered that the other Unit 2 SG tempering lines may have also experienced similar
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waterhammer conditions during the previous refueling outage. The licensee had perfomwd visual examination walkdowns of these lines inside containtnent and found no eviderne of damag b. Feedwater Temoering Line and Pine Sucoort Damage The licensee identified five of eight hargers on the SG 20 tempering line 2FW87CD-6
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i inside the containment and one pipo support outside containment, which had sustained damage or had been visibly affected by the waterhammer even t A constant load (spring can) type pipe support 2FWO9002C, (the support closest to SG 2D) had separated and broken ofifrom its steel support structure. The upper support attachment connection had been bent, the lower rod had been broken and the pipe clamp end of the support had sh'TM approximately 30 degrees from the vedical axi Pipe supports 2FWO9008R and 2FWO9012R had loose pipe clamps that had shifte Pipe support 2FWO9004X had loose lock nuts. Outside containment the pipe support 2AF07030 pipe clamp had shifted slightly. Inspectors reviewed the licensee correciive
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actions taken for each of these pipe supports which restored them to original design parameters and found them to be adequat One side of the pipe support 2FWO9013G baseplate (inside containment) had been pulled out from the concrete wall. Specifically, two of four ccncrete expansion anchors (CEAs) had been pulled out approximately 0.75 inches from the wall. The licensee had used ultrasonic testing (UT) equipment to verify the integrity and length of the affected CEAs and had reset them and applied the desigre torque to the attachment nuts. The licensee documented their technical basis for accepting this pipe support in calculation 13.2-BWR-97-1003, Revision 5. In this evaluation, the licensee accepted the recairnd pipe support for continued operation based om CEA integrity and design length
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(established by UT), lack of concrete cracking or spalling at the concrete surface around the affected CEAs, resetting of the CEAs to minimum embedment and reestablishment of the design " instal'stion torque"on the CEAs. This approach was discussed with the licensee and the Office of Nuciear Reactor Regulation staff on a conference c JI held November 13,1997, and no further technice! issues were identified. Inspectors questioned the engineering staff on documentation of the as-found individual measured
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) j-CEA pull out distances. This prompted the licensee to initiate a change to calculation 13.2 BWR-97-1068 to incorporate an engineering walkdown sketch with the as-found
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CEA projection measurements, to ensure that this data was captuud in a permanent plant record.
l The tempering line pipe had impacted a feedwater snubber support 2FWO5011S i
(discussed below) wh!ch had created a slight flat spot on the tempering line. The licensee had performed a magnetic particle examination at the affected location and had .
g cetected no relevant indications.
L b.3.2 Main Feedwater Line Pioe Sucoort Damaoe The SC D main feedwater line inside containment had been impacted by the tempering l; line at the feedwater line snubber 2FWO5011S pipe attachment. This attachment had-been shifted (rotated about the piping axis), which fully extended the lower snubber for
- this support. The licensee corrective actions included removal, testing and resetting of this support and nearby snubber supports 2FWO5013S and 2FWO5022S. The inspector considered these licensee corrective actions appropriat NSWP-A-15,."ComEc Nuclear Division Integrated Report!ng Program," Revision 1, paragraph 6.1.1 required "All station individuals or contractors should initiate an Exhibit A, " Problem Identification Form (P!F)," when a problem is recognized." and BwAP
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330-10 "Operabil_ity Determinatior s," Revision 3E1, paragraph F.5, required "Any on-site personnel knowledgeable of a possible OPERABILITY ISSUE, identified to them by any
. source, MUST promptly notify the Shift Manager (SM;, or designee and write a '."
~ Contrary to these requirements, the inspector identified that the licensee had fa 4 to initiate a PIF (documenting the potenticily damaged snubbers 2FW0011S, 2FWO5013S, & 2FWO50228) unt' after the damage had been identified (on November 10,1997 in action requests 970084651,970084666,970084667) and corrective actions had been completed. The licensee's failure to follow procedural requirements to istue a PlF when the problemwas recognized is an additional example of a violation of 10 CFR
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50, Appendix B, Criterion V (VIO 50-457/97021-03(b)(DRS)).
b.3.3 Steam Generator 2D Potentially Damaoed The licensee had requested and received vendor (Westinghouse) conclusions on the
. potential for dar"sge to tne SG D auxiliary feedwater nozzle and internals as a result of ( this event, in the NSD-E-SGDA-97-207 letter dated November 14,1997, Westinghouse concluded that there had likely been no damage to the internal discharge pipe shear plate (internal pipe support) for the SG D auxiliary feedwater nozzle. However, Westinghouse concluded based on the estimated pressure pulse from the waterhammer event, that the nozzle internal discharge pipe sad thermal sleeve had likely been expanded. Westinghouse considered that this would potentially impact the long term fatigue life of this nozzle due to the loss of insulating effect from the reduced thermal sleeve gap. The licensee documented this issue in PIF A1997-05171 issued on November 20,1997 and considered the auxiliary feedwater nozzle operable based on
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'.i-t the Westinghouse conclusions discussed above. The licensee intended to close this PIF based on inspections of the thermal sleeve and/or fatigue analysis of the nozzle included as longer term corrective actions for PlF A1997 501 ,'
b.3.4 hmoerino Flow Control Valve (2FWO34D) Failure The licensoe uocumented in PlF A1997-5010 that 2FWO34D stem had separated from the disc. The !!censee completed repairs to this valve in work request 960093777, which included installation of a new style plug assembly and recalibration of the valve,'
The licensee preliminary investigation into the fai!ure of 2FWO34D concluded that an incomplete or partial engagement of the reta'ning ring in the pilot plug groove had allowed the assembly to disengage under the 1000 pounds per square inch differential pressure induced across tht valve during the waterhammer event. The failed assembly
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allowed the valve stem to travel full stroke without moving the pilot plug (e.g. the valve remained closed). Short and Lona Term Corrective Actions l
Three short term corrective actions were taken by the licenses for this event, which included: inspections and repairs to restore the feedweter system, revision to the Station Startup Procedure (BwGP 100-2) to require minimal differential pressure across the preheater bypass valve prior to stroking the valve, and training on the waterhammer event for operations and enginning department personne Fifteen longer term corrective actions to prevent recurrence were identified by the licensee for this event, which included: evaluating the fatigue life of the affected SG nozzle, evaluating the need for additicnal feedwater vent valves, reviews of three other systems susceptible to waterhammer, personnel training and procedure reviews, Additionally, the licensee intended to perform an effectiveness review of the corrective actions completed for the water hammer even The correctiva actions discussed above for the waterhammer event are included in the final Root Cause Report issued by the licensee on December 19,1997, inspectors reviewed the full scope of planned corrective actions, as discussed in this report, and considered the actions sufficier.tly comprehensive to ensure the continued integrity of affected systems and components and to prevent recurrence of this even Conclusions Inspectors considered the licensee event investigation and assessment effective et determining the sequence of events and cause of the 2D feedwater waterhammer event. Further, apprcpriate engineering evaluations had been implemented for the components and systems affected by this event. However, inspectors identified that the
. licensee had failed to follow procedural requirements to issue a PlF when a prnblem was identifierl (damaged feedwater snubbers), which is considered an example of a violation of 10 CFR 50, Appendix B Criterion i t
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I Short and long term licensee corrective were sufficiently comprehensive to establish the ,,
integrity of the affected systems and prevent recurrence of this waterhammer event
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caused by an inadequate feedwater system fill and vent procedure.
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V...Mangement Meetinga X1 Exit Meeting Summary i
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The inspectors presented the inspection results to members of licensee management at the conclusion of the inspection on November 21,1997, and final phone exit on January -
i 15,1908. The licensee acknowledged the findings presented and did not identify any of ,
the potential report input discussed as proprietary,
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PARTIAL LIST OF PERSONS CONTACTED Commonwealth Edison
- B. Acas, Support Engineer R. Byers, Maintenance Manager M. Cassidy, NRC Coordins,br W. Cote, ISEG Engineer F. Lentine, Support Engineering Supervisor
= M. Reigel, Quality Assurance Manager
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l G. Schwartz, Station Manager B. Wagner, Operations Manager "
lilinois Deoartment of Nuclear Scfetv 4 T. Esper, Resident inspector NaC C. Phillips, Senior Resident inspector
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ll4SPECTit,N PROCEDURES USED IP 93702 PROMPT ONCITE RESPONSE TO EVENTS AT OPERATING POWER '
REACTORS IP 92720 CORRECTIVE ACTION e
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ITEMS OPENED CLOSED or DISCUSSED
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DD10 50-457/9702101(DRS) VIO Failure to establisn and implement en adequate feedwater o system fill and vont procedure (Section 021).
50457/97021-02(DRS) VIO Failure to irnplement a procedure change for an
'nadequate startup pa:cedure (Section O2.1).
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50-457/97021-00(DRS) VIO Failure to hitiate a PlF for potentially damaged snubbers (Section 02.1 and E2.1).
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LIST OF ACRONYMS USED CEA Concrete Expansion Anchor EPRI Electric Power Research Institute
'F Degrees Fahrenheit
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gpm Gallons per Minute ISEG Independent Safety Engineering Group NDE Nondestructive Examir.ation
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PDR Public Document Room psig Pounds per Square Inch Gauge -
OOS Out of Service PlF Problem identification Form PWR Pressurized Water Reactos SG(s) Steam Generator (s)
SM Shift Manager
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TS Tnchnical Specificatio.,
UT Ultrasonic Testing VIO Violation N
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- e LIST OF DOCUMENTATION REVIEWED Process computer data plots of pressures, flowrotes and temperatures in the SG D feedwater line tempering line and tempering bypass lino, g
P:F A1997-05010 "2D FW Line Water Ham ner" issued on November 10,199 PIF A1997-05055 " Supports Damaged Due to 3ystem Transient" issued on Novensber 12, 199 PlF A1997-05074 * Snubbers 2FWO50118,2FWO5013S, & 2FWO5022S Suspect" issued on November 13,199 '
PIF A1997-5090 * Flat Spot indication Identified on Line 2FW87CD-6" issued on November 14, 1997 BwAP 100-20 * Procedure Use and Adherence," Revision 7E1, 2Bw'3P 100-1 "P!ar.; Heatup," Revision 1, 2BwGP 100-2 " Plant Startup," Revision 9.-
BwOP CD/CB-3."Fi'l and Vent of the Condensate System," Revision 17E BwOP FW-3, ' Fill and Vent of the Feedwater System," Revision 6, 2BwOA SEC-6 " Loss of Feedwater Tempering Line Subcooling Unit 2," Revision ,
Feeowater Out of Service (OOS) 97000447 Condensate System OOS 97000168 Process Review Oversight Committee Meeting Minutes of November 13,199 Draft Root Cause Team Investigation Report " Unit 2 Feedwater Tempering Line Hydraulic Pressure Transient Caused By inadequate System Venting," copy dated November 18,1997.
O Root Cause Report " Water Hammer Caused By inadequate Venting While Opening 2FWC390 Valve," Revision 7, issued Dt.cem' 3r 19,199 '
Nondestructive examination (NDE) records for the affected SG D ;tmpering feedwater line 2FW87CD-6 and NDE reco. ds for SG A, B and C tempering line Action 'o .ests (AR) testing /cos,ecting affected feedwater system piping supports (AR#
9700844u5,970084403,970084651,970084666,970084667,970084647,970084655, 970084654,970084650,970085354).
NSD-E-SGDA-97-207 letter dated November 14,1997 from J.L. Houtman (Westinghouse) to
' Amy Ferko (Commonwealth Edison).
Calculation 13.2.18-BWR-97-1068 " Pipe support 2FWO9013G - assessment for repairs / reinstallation due to waterhammer event," Revision