05000263/LER-2001-009
| Docket Number | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(a)(2)(i)(B), Prohibited by Technical Specifications |
| Initial Reporting | |
| 2632001009R00 - NRC Website | |
Description On March 28, 2001, during a mid-cycle plant outage, installation of Modification 01Q075 was in progress to upgrade the fuel zone reactor vessel water level channels' to utilize the safeguards vessel level reference columns previously modified to be more resistant to reference leg "flashing.
During work on piping2 associated with the B fuel zone channel, it was found that the as-built piping connected to vessel penetration X-29A was different than shown on the Piping & Instrumentation Diagram (P&ID) used in the modification package. This condition was confirmed by running demineralized water through the various isolated piping runs connected to penetration X-29A.
The P&ID shows instrument piping downstream of containment penetration X-29A splitting into two branches. The first branch connects to feedwater level instrumentation on panel C56 and fuel zone level and safety/relief valve (SRV) low-low set pressure switches' on panel C122 via excess flow check valve.' XFV-26. The second branch connects to residual heat removal (RHR) permissive interlock pressure switches' on panel C122 via excess flow check valve XFV-57.
Panel C56 is on elevation 962' and panel C122 is on elevation 935' in the Reactor Building. Refer to Figure 1.
Investigation found that the piping between C56 and C122 were rolled in the vertical pipe run between floors. This resulted in the RHR pressure switches actually being connected to XFV-26 and the fuel zone and SRV low low set pressure switches connected to XFV-57. The operability of instrumentation connected to XFV-26 and XFV-57 was not affected by the piping error since it made no difference which excess flow check valve supplied each instrument.
Review of the excess flow check valve surveillance test procedure showed that the low side instrument tap of feedwater level transmitter LT-6-52B was being used to bleed off pressure when testing XFV-26. The piping routing error did not prevent a valid test of XFV-26. The instrument tap for RHR permissive Interlock pressure switch PS-2-3-49B was used in the procedure to bleed off pressure when testing XFV-57. Because the RHR permissive interlock pressure switch was actually connected to XFV-26 due to the piping error, a valid test of XFV-57 was not performed and XFV-26 was actually being tested twice.
1 EIIS System Code: � IP 'EIIS Component Code: TBG El IS Component Code: PS 4EIIS Component Code: FCV 5 EI IS Component Code: PS Modification 01Q075 was revised to include the restoration of the B instrumentation piping to conform to the original design specified on the P&ID.
Event Analysis
Analysis of Reportability Technical Specification 4.7.D.1.b states: "At least once per operating cycle the primary system instrument line flow check valves shall be tested for proper operation." Also, Technical Specification 4.15.B.1 states: "Inservice testing of quality group A, B, and C pumps and valves shall be performed in accordance with the requirements for ASME Code Class 1, 2, and 3 pumps and valves, respectively, contained in Section XI of the ASME Boiler and Pressure Vessel Code and applicable Addenda as required by 10 CFR 50, Section 50.55a(g) except where relief has been granted by the Commission pursuant to 10 CFR 50, Section 50.55(a)(g)(6)(i), or where alternate testing is justified in accordance with Generic Letter 89-04.
10 CFR 50.73(a)(2)(i)(B) requires reporting of "any operation or condition which was prohibited by the plant's Technical Specifications except when ... (2) the event consisted solely of a case of a late surveillance test where the oversight was corrected...." It was conservatively determined that this event did not meet the criteria for a missed surveillance test because of the long period during which XFV-57 was not tested. The event is therefore being reported in accordance with Section 50.73(a)(2)(i)(B).
Safety Significance
We believe that this event has a low safety significance based on the following factors:
1. The instrument piping routing error did not result in the inoperability of any equipment.
2. Following discovery of this event, XFV-57 was removed and bench tested successfully.
3. An extent of condition evaluation revealed no other similar excess flow check valve P&ID discrepancies.
Cause
2001 — 009 — 00 4 OF The piping associated with the A reactor vessel fuel zone level instrumentation was tested and found to match the reactor vessel instrumentation P&ID. A contact made with General Electric confirmed that the intended piping design was shown on the P&ID.
Field investigation confirmed that the true cause of the occurrence was a construction error resulting from "rolling" of the B leg piping in passing through the concrete structure of the Reactor Building between elevations 935' and 962'.
A review of all revisions to the P&IDs for piping in this area confirmed that no changes had been made since the original construction of the plant. It is believed that the error was made at that time.
Corrective Actions
The scope of Modification 01Q075 was expanded to include routing of the B reactor vessel instrumentation piping to eliminate the error caused by "rolling" of the piping between elevations 935' and 962'. Modification 01Q075 was satisfactorily completed on the B leg piping.
Demin water was injected at various instrument taps with the instruments and associated trips bypassed to confirm that the revisions to the B leg piping were correctly installed.
The configuration of the piping associated with the A reactor vessel fuel zone level instrumentation was tested and verified to match the P&ID. Modification 01Q075 was satisfactorily completed on the A leg piping.
An extent of condition evaluation was completed and no other similar excess flow check valve P&ID discrepancies were found. The results of this evaluation are document in a Condition Report.
Failed Component Identification None Similar Events None
DRYWELL
PENETRATION
X-29A ELEVATION 980'
FLOOR
962' TO 935' INSTRUMENT RACK C122 ELEVATION 935' Instrument Piping "Rolled" Between Floors During Construction in this Location
REACTOR
VESSEL
NOZZLE
N-11B
FUEL ZONE REF LEG
& LOW-LOW SET
PRESSURE SWITCHES
s's--- � ..----"-i '.7 To 935'
RHR INTERLOCK
PRESSURE
SWITCHES
(PRESSURE BLEED FOR XFV-57 TEST) Figure 1 Simplified Drawing of As-Designed B Reactor Vessel Instrument Piping
INSTRUMENT RACK
C56 ELEVATION 962'
FEEDWATER LEVEL
INSTRUMENTS
(PRESSURE BLEED FOR XFV-26 TEST) XFV-26 1E' � XFV-57 I*
REACTOR
VESSEL
Method of Discovery
During modification 01Q075 as described above.
Reactor Power 0% s/d Shift Manager Notification SM: Bruce MacKissock D Date 3/28/01 Immediate Actions Taken General Condition Report � gen20011860.doc 05/23/01 Review of surveillance 0255-20-IA-1 and P&IDs M-115, M-116, and M-116-1 and walkdown of piping. No other immediate actions since the safeguards, feedwater, and fuel zone instruments are isolated per the modification.
II. � Screening A. � Prompt Operability Determination 1. Does the condition affect safety-related SSCs or Z Yes SSCs covered by the Technical Specifications? Go to II.A.2 2. Have the involved SSCs been declared Z Yes inoperable? Go to II.B 3. Are the involved SSCs CLEARLY operable? ❑ Yes Go to II.B 4. Is there REASONABLE EXPECTATION the [-I Yes SSCs are operable? Perform an operability evaluation 5. Check this box to insert an operability evaluation. ❑ ❑ No Go to II.B ❑ No Go to II.A.3 ❑ No Go to II.A.4 ❑ No Notify Operations and go to II.B B. Compliance with Technical Specifications Since the plant is in cold shutdown, the check valves are not required to be operable. Therefore, we are not currently in violation of technical specifications. However, we were not in compliance with technical specifications 4.7.D.1.b and 4.15.B.1, as noted in the description, during past operation.
C. NRC 10CFR50.72 or State notification required Not required.
D. Personnel Qualifications Affected None.
General Condition Report � gen20011860.doc 05/23/01 E. Initial Extent of Condition Review 1. Identify any immediate actions necessary for other safety-related equipment as a result of this condition.
It is possible that the same condition exists on the A reference leg. That leg is protected during work on the B reference leg. Determination must await completion of the B leg work.
Testing on 3/30/01 showed that the configuration on A reference leg configuration matches the P&ID and therefore does not have the problem.
F. 10CFR Part 21 Screening 1. Is the equipment associated with this Condition Report Z Yes ❑ No safety related? 2. Does the equipment contain a defect, does it not meet ❑ Yes Z No purchase specifications or has there been a failure to comply with NRC regulations? If both of the above = Yes, and this has not already been reported to the NRC, you should insert a Part 21 evaluation.
3. Has the NRC been formally notified of this issue? � ❑ Yes Z No 4. Check this box to insert a Part 21 evaluation. � ❑ III. Assign Assessor (Provide management expectations, person hours, etc.) John Grubb is assigned as the management sponsor for this CR. John has determined that the condition requires an LER and that an investigation report is not necessary IAW 4AWI-10-01-05; the LER is considered the investigation report.
IV. Assessment A. Detailed Description (if necessary to complement the Initiator's Description) Description is accurate.
B. Operability (for Safety-Related SSCs and SSCs covered by Tech Specs) 1. Changes to the Prompt Operability Determination (if any).
None required; plant was in cold shutdown at the time of determination.
2. Identify any Inoperable SSCs and the length of time of inoperability (Include any safety significance in the section below).
Removal and testing of the single excess flow check valve following the General Condition Report � gen20011860.doc 05/23/01 determination that it had not been previously tested showed that the valve operated properly and within specification. The conclusion is that no SSCs were ever inoperable.
C. Reportability 10CFR50.73(a)(2)(1)(B) states: "Any operation or condition which was prohibited by the plant's technical specifications except when (1) the TS is administrative in nature; (2) the event consisted solely of a case of a late surveillance test where the oversight was corrected, the test was performed, and the equipment was found to be capable of performing its specified safety functions; or (3) the TS was revised prior to discovery of the event such that the operation or condition was no longer prohibited at the time of discovery of the event." In NUREG-1022 Rev. 2 on page 33, it states "Reporting is not required if an event consists solely of a case of a late surveillance test where the oversight is corrected, the test is performed, and the equipment is found to be capable of performing its safety functions." A survey of NMC members resulted in essentially two recommendations. Most felt that the issue did not warrant an LER under the 50.73 rule while some felt that even if the event didn't meet the technical requirements for reporting, it would be a good idea to voluntarily submit a report. The plant has decided to submit an LER for the event.
D. Final Extent of Condition Review 1. Determine if this condition has generic implications on other equipment, systems or programs.
Division A does not have the same problem. This was confirmed prior to the work on the A instrument leg.
Review of walkdown drawings performed for seismic qualification of small bore piping for Project 88Z007 did not show any other significant piping or documentation problems (CR 20011840).
2. Scope of Review Demin water was injected at various instrument taps with the instruments and associated trips bypassed to determine that actual piping paths prior to the work on the A leg.
Review of CR 20011840, Apparent Discrepancies on P&ID Lead to Connecting to Wrong Instrument Line.
E. Cause Determination 1. Evaluation The cause of this occurrence was an original construction error that resulted in a difference between the instrument lines in the plant and the P&ID. The first presumption was that the P&ID was incorrect. However, after further analysis of other drawings and the results of testing on the A General Condition Report � gen20011860.doc 05/23/01 leg and after conversations with GE on plant design, it is concluded that the P&ID shows the piping the way it was originally designed. The actual pipe connections on the B leg were "rolled" between elevations 935' and 962'. A review of all revisions of the P&IDs also shows that piping in this area had not been changed. Thus, it is concluded that this condition has existed since the plant was constructed.
2. Scope of Review Review of all revisions of the applicable P&ID.
Walkdowns of the actual pipe runs which illustrate the difficulties encountered when the piping trays traverse concrete structures.
Analysis of surveillance 0255-20-ID-1, Excess Flow Check Valve Test Procedure to determine which valves may have gone unchecked due to the discrepancies.
Review of CR 20011840, Apparent Discrepancies on P&ID Lead to Connecting to Wrong Instrument Line.
F. Safety Significance
Since the affected excess flow check valve tested successfully, the safety significance of missing previous tests is negligible. Since the extend of condition evaluation did not identify any other similar drawing or P&ID discrepancies, the safety significance is none.
G. Actions Taken Excess Flow Check Valve XFV-57 was detached and bench tested successfully (WO 0106899).
APR 20012394 written to revise surveillance 0255-20-ID-1, Excess Flow Check Valve Test Procedure to assure XFV-57 is properly tested.
H. Maintenance Rule Functional Failure � [S] No V. � Due Date Extensions Old Due Date New Due Date Date that the Due Date was Changed Reason for the Change Who Authorized the Change 4/27/01 5/29/01 4/30/01 To match the due date of the associated LER S A Engelke General Condition Report � gen20011860.doc 05/23/01 VI. Review Comments � (if any) VII. Approver Comments � (if any) VIII. Other Comments FINAL REVIEW AT OC MTG 2269 ON 5/23/01.