ML20217H534
| ML20217H534 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 04/28/1998 |
| From: | Ewing E ENTERGY OPERATIONS, INC. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 50-382-97-25, W3F1-98-0091, W3F1-98-91, NUDOCS 9804300002 | |
| Download: ML20217H534 (9) | |
Text
,,y EntIrgy Oper;tioni, Inc.
Killona. LA 70066 Tel 504 739 6242 Early C. Ewing,111 Director Nuclea SafeN & Regulatory Affairs W3F1-98-0091 A4.05 PR April 28,1998 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555
Subject:
Waterford 3 SES Docket No. 50-382 License No. NPF-38 NRC Inspection Report 97-25 Reply to Notice of Violation Gentlemen:
In accordance with 10CFR2.201, Entergy Operations, Inc. hereby submits in the response to the violation identified in Enclosure 1 of the subject inspection Report. On April 9,1998, an extension of the original 30-day response date until April 28,1998, was granted to Waterford 3 by Ms. L. Smith, NRC Recion IV, acting on behalf of Mr. T. Stetka.
If you have any questions concerning this response, please contact me at (504) 739-6242 or Tim Gaudet at (504) 739-6666.
Very truly yours, E.C. Ewing i
- Director,
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Nuclear Safety & Regulatory Affairs I
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ECE/ ell /rtk gu3 Attachment cc:
E.W. Merschoff (NRC Region IV), C.P. Patel (NRC-NRR), J. Lieberman (Office of Enforcement), J. Smith, N.S. Reynolds, NRC Resident inspectors Office 98043o0002 980428 DR ADOCK 050o 2
Attachmnnt to W3F1-98-0091 Page 1 of 8 ATTACHMENT 1 ENTERGY OPERATIONS. INC. RESPONSE TO THE VIOLATION IDENTIFIED IN 1
ENCLOSURE 1 OF INSPECTION REPORT 97-25 VIOLATION NO. 9725-04 10 CFR Part 50, Appendix B, Criterion V, requires, in pait, that activities affecting quality shall be prescribed by procedures appropriate to the circumstances and shall be accomplished in accordance with these procedures.
Procedure W2.501, " Corrective Actions," Revision 6, Section 4.1, requires that condition reports be generated when licensee personnel identify an adverse I
condition. Section 3.1 of the procedure defines an adverse condition as an event, defect, characteristic, state or activity, which prohibits or detracts from the safe, efficient operation of Waterford 3. The adverse condition was further defined to include nonconforming conditions.
Contrary to the above, from October 29 through December 1,1997, the licensee i
failed to initiate a condition report when an adverse condition was identified.
Specifically, a condition report was not initiated when industry data indicated that Main Feedwater Isolation Valves FW-184A and B, an Anchor-Darling hydraulically-operated gate valve, operated with a valve factor (a measure of the friction resistance of the valve), which did not conform to the valve factor assumptions that were made in the valve actuator capability assessment. Industry data indicated that these valves operated at a valve factor of 0.4, but the calculations for sizing the actuators for Valves FW-184A and B were based on a valve factor of 0.2.
This is a Severity Level IV violation (Supplement 1) (50-382/9725-04).
RESPONSE
Summary Entergy Operations Inc. has carefully evaluated the information in Violation 9725-04 and has reached the following conclusions:
(a) Entergy Operations Inc. denies that a failure to comply with Procedure W2.501,
" Corrective Action," Revision 6 existed.
(b) Entergy Operations Inc. admits that an opportunity was missed to question the valve factor used during installation of design change DC-3364 in 1995.
(c)
Entergy Operations Inc. admits that the recommendations provided by the l
Operational Experience Engineering (OEE) group based on its evaluation of Information Notice 96-48, " Motor-Operated Valve Performance issues", and the subsequent Components Engineering response were weak in that this EPRI MOV
[
L Attachmsnt to i
3 W3F1-98-0091 Pago 2 of 8 program evaluation was not formally extended to air-operated or hydraulically-operated valves (AOVs/HOVs).
Basis for Enterav Operations Inc. Position (a) Entergy Operations Inc. denies that a failure to comply with Procedure W2.501,
" Corrective Action," Revision 6 existed.
j Basis for Denial l
l The violation states tnat Entergy Operations Inc. knew that an adverse condition j
existed between October 29 and December 1,1997, and yet failed to comply with i
L our corrective action program by not documenting this adverse condition in a condition report (CR). Entergy Operations Inc. believes our corrective action program distinguishes between potential and actual adverse conditions. The issue with the 0.2 valve factor for the Main Feedwater Isolation Valves (MFIVs), FW-184A(B), represented a potential adverse condition, appropriate actions were taken based on that potential adverse condition, and once an actual adverse condition with the MFIVs was identified (for maximum expected differential pressure), a CR was written.
l Backaround (1) Procedure W2.501 Requirements Procedure W2.501, " Corrective Action", Revision 6, requires the following:
Section 5.1 Allindividuals working at Waterford 3 are responsible for:
5.1.1 identifying and reporting adverse conditions in accordance with section 6.1 of this procedure.
Section 6.1 of procedure W2.501, " Corrective Action," requires in part:
6.1.1 An individual who identifies an adverse condition shall:
6.1.1.6 When a potential adverse condition has been identified that requires further investigation or analysis to validate the condition or facilitate a proper operability /reportability review, such investigation or analysis should be carried out expeditiously and appropriate plant management should be made aware of the potential adverse condition; and 6.1.1.7 When an adverse condition has been identified, the originator should carry the CR to the Shift Support Center j
or the Control Room to facilitate a prompt operability /reportability review.
r Attachment to W3F1-98-0091 Page 3 of 8 i
l Thus, the Waterford 3 corrective action program provides that when a potential adverse condition is identified, the appropriate action is to conduct an investigation or analysis in a timely manner to confirm whether or not an adverse condition l
exists, if the results of the investigation or analysis indicate an adverse condition exists, a CR is written and taken to the Shift Support Center or Control Room.
Conversely, if no adverse condition is identified, no CR is written.
(2) Potential Adverse Condition with FW-184A(B)
Information Notice 90-72 was issued in November 1990 to alert licensees to issues regarding testing of parallel disc gate valves. A 1992 closure time analysis, calculation EC-M92-009, evaluated a 0.3 valve factor for the FWlVs, basing the evaluation on the information stated in IN 90-72. Using this valve factor, along with information provided by the valve manufacturer on actuator capability, it was i
determined that the valve required thrust was approximately equal to the available actuator thrust. Therefore, the valve was determined capable of closing with a valve factor of approximately 0.3. The applicability of this valve factor was again confirmed in December 1997, with the immediate operability discussion in CR 2759. The available valve factor was found to be 0.31, using conservative accumulator pressures and a differential pressure equal to the maximum operating pressure.
Data gathered by Waterford 3 personnel shows that a valve factor of 0.3 is acceptable for the 20" FWlVs, based on the limited industry test results available and engineering judgment. Anchor Darling (A/D) tested an A/D 6" parallel disc gate valve which resulted in a valve factor of 0.305 during blowdown conditions with a differential pressure of 1481 psid and a temperature of 580 F (Reference A/D Report CTS-27) which is similar to the design basis conditions for the FWlVs. The FWlV design conditions are a differential pressure of 1571 psid and a temperature of 480 F. In addition, EPRI tested an A/D 6" parallel disc gate valve which l
resulted in a valve factor of 0.331 at isolation during blowdown conditions with a differential pressure of 1270 psid and a temperature of 510 F (Reference EPRI Topical Report TR-103237 Rev. 2).
The EPRI MOV Performance Prediction Program, EPRI Topical Report TR-10237, Table 11-1, page 11-13, concluded that valve factors decrease with increasing contact stress. Therefore, considering the valve factors derived from the
/JD and EPRI test data were for a 6" valve with lower contact stresses, the valve Octor for the 20" FWlVs should be lower due to the higher " disc to seat" contact mress in these larger valves. EPRI testing also indicated the apparent valve factor tends to decrease with increasing differential pressure. The FWlVs are large 20" valves with 18" internals, and are potentially subjected to pressures as high as 1571 psig. Therefore, based on industry test data a valve factor of 0.3 is appropriate.
In December 1997, the NRC E&TS Inspection team identified that the valve
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factor used by Anchor Darling in the closure time analysis for the FWlVs, performed as part of the 1995 accumulator modification, was 0.2. The use of this valve factor in this modification had not been identified by Waterford 3 at m
Attachm:nt to W3F1-98-0091 Page 4 of 8
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- this time, it is and was known by Waterford 3 personnel that according to the limited industry test data, a 0.2 valve factor may be nonconservative. CR '
2759 was written to document resolution of the NRC inspection team's concern with the impact of the higher valve factor on the FWlVs and to document the nonconservative assumption. Initiation of a more in-depth review of the valve's design basis and abilities was initiated in response to e
CR-97-2759. At the time CR-97-2759 was written, an actual adverse condition had not yet been identified because the FWlV evaluation confirmed the available valve factor was approximately 0.3 which was in agreement with the 1992 closure time analysis and the most recent industry test data. The actual capability of the valve was believed to be satisfactory even though a nonconservative valve factor had been used by the vendor in developing modification DC-3364.
Thus, Entergy Operations concludes that the valve factor issue with FW-184A(B) represented a potential adverse condition. Appropriate actions were taken in accordance with Procedure W2.501 to investigate the valve factor issue to determine if an adverse condition existed, no adverse condition with FW-184A(B) was identified during this investigation, and the valve was capable of closing with a valve factor of approximately 0.3.
(3) FW-184A(B) Maximum Expected Differential Pressure As a result of a design basis review performed as a corrective action for CR-97-2795, it was determined that the maximum expected differential pressure seen by the FWlVs in the valve's worst case design basis scenario is higher than the originally assumed system design pressure. This, along with the 0.3 valve factor assumption and the use of the low alarm setpoint, less tolerance and instrument inaccuracies in the hydraulic accumulators, has resulted in the requirement to have both accumulators in service to ensure valve closure against the maximum expected differential pressure in the required time. On March 6,1998, CR 98-0337 was written to document this adverse condition and initiate immediate actions to ensure operability was maintained.
(b) Entergy Operations Inc. admits an opportunity was missed to question the valve factor used during installation o' design change DC-3364 in 1995.
Design change DC-3364 installed larger accumulators and added stop tubes inside the accumulators, to ensure the required nitrogen volume is maintained. In an addenda to the original Anchor Darling closure time analysis to incorporate the modifications, a 0.2 valve factor was used by the vendor. The previous closure time analysis performed by Waterford 3, which used a 0.3 valve factor, was voided because the modification changed the actuator flow control settings which invalidated the calculation.
Entergy Operations Inc. believes the probable cause of this missed opportunity was an inadequate review of the Anchor Darling supplied documentation. The documentation was never formally added to the Waterford system (i.e., given a calculation number) and a reasonableness review was not performed.
Attachment to W3F1-98-0091 Pag @ 5 of 8 (c)' Entergy Operations Inc. admits the recommendations provided by the Operational Experience Engineering (OEE) group, based on its evaluation of Information Notice 96-48, " Motor-Operated Valve Performance issues", and the subsequent Components Engineering response were weak in that the EPRI MOV program evaluation was not formally extended to air-operated or hydraulically-operated valves (AOVs/HOVs). This occurred even though the IN and the OEE evaluation both identified that the EPRI program provided important information applicable to gate, globe, and butterfly valves, regardless of the type of actuator operating the valve.
I Entergy believes the probable cause for this weakness is that the response was prepared with the same focus as the IN which was MOVs and GL 89-10 programs.
Waterford 3 realizes that AOVs and HOVs hold the same importance and share some of the same issues. However, AOV/HOV program development is for the most part in its infancy.
1 No specific mention of AOVs or HOVs was made in any of the responses to the IN. However, other power-operated valves were looked at. In the actions established by Components Engineering from their review of IN 96-048, Engineering Request (ER) W3-98-0170-00-00 has been issued to Design j
Engineering to determine a valve scope and replacement frequency for all butterfly valve seats (one of the findings addressed in the IN). Thus, Waterford 3 extended the scope of its evaluation of one IN recommendation to all power-i operated valves regardless of the actuator type.
It has been previously recognized at Waterford 3 that AOVs and HOVs are subject to many of the same lessons learned as the MOVs, and appropriate actions have been taken. An Entergy AOV Peer group was established in 1994, and discussions of an AOV Design Engineering Administrative Manual (DEAM) began. The purpose of this DEAM is to provide for the basic components to be included in Entergy Operations Inc. site AOV programs and provide assurance that AOVs providing active safety functions and balance-of-i plant AOVs which are critical in terms of radiation exposure, reliable operation, or cost perform as required, included in this DEAM are references to MOV lessons learned, and the expectation is to incorporate MOV lessons learned into site AOV Programs. This DEAM was approved by all Entergy sites in January of 1998.
During the time that the IN 96-48 evaluation by Components Engineering was'in preparation, the site AOV/HOV program was in development. In September of 1997, a contract was awarded to ERIN Engineering to perform design basis review calculations on the first phase of safety related AOVs (over 100 AOVs).
As the valves undergo their design basis reviews, and calculations are prepared, the parameters established / discovered through MOV testing and experience will be included. This was the first documented step toward the development of the Design Engineering side of the AOV Program. This process parallels the GL 89-10 MOV design basis review effort which took several years to complete in accordance with the schedule outlined in GL 89-10. As the MOV design basis reviews and/or testing were completed, CRs were initiated when 4
Attachmnnt to W3F1-98-0091 Page 6 of 8 adverse conditions were identified. The engineering contractor (ERIN) selected
' to perform the AOV Design Basis Review (DBR) calculations also prepared the design basis review calculations for the Waterford 3 GL 89-10 MOV Program and participated in the three GL 89-10 MOV inspections (Phase I, Phase ll, &
Closure). Therefore, considering their GL 89-10 experience, Waterford 3 selected ERIN to perform the AOV DBR calculations with the expectation that the MOV lessons learned would be incorporated into the calculations.
Prior to contract issue, the AOV Design Engineer began to scope the Waterford 3 AOV/HOV Program valves. These included approximately 170 active safety related AOVs and six active safety related HOVs. Categorization and scoping were performed in accordance with the draft Entergy AOV Program DEAM and industry guidance. This scoping is not yet complete, but the calculations have begun. The scoping of the first phase of design basis review calculations was performed in accordance with the draft AOV DEAM and industry information.
The first phase included high and medium Probablistic Risk Assessment (PRA) valves. These valves are risk significant and important to the safe shutdown of the plant. Also included were valves associated with outstanding CRs, such as the Emergency Feedwater Flow Control and Isolation Valves and safety related AOVs with WKM actuators. Some safety related valves without active safety functions were included because of the WKM inclusion. Valves were also reviewed for safety significance and maintenance history. Some valves left out of the initial scope were valves that had previously developed sizing calculations, valves in ventilation systems, and valves with little safety significance. In the case of the FWlVs, closure of these valves is not considered risk significant, not identified as a failure that would prevent decay heat removal, and not included in the PRA model. Thus, the FWlVs were not included in the first phase of calculations.
MEASURES THAT HAVE BEEN TAKEN (a) On January 7,1998, DEAM EP-G-003-00, "AOV Program Plan", was issued to provide guidance in establishing site AOV programs. The DEAM effectively summarizes appropriate industry experience related to i
AOV performance, including lessons learned from industry MOV programs.
(b) Closure time is addressed, using a 0.3 valve factor and the determined i
maximum expected differential pressure, in the detailed engineering evaluation for CR-98-0337. This evaluation has concluded the valve is capable of closing within the required 5 seconds under maximum expected differential pressure.
(c) The sizing of air-operated parallel disc gate valves installed since 1995 has incorporated MOV lessons learned via the use of conservative valve factors, as specified by Waterford 3 engineers.
Attachm::nt to W3F1-98-0091 Page 7 of 8 In 1995, the Reactor Hot Leg injection Leakage Drain (SI-301 and 302) globe valves were replaced with A/D double disk gate valves; the Safety injection Tank Leakage Drain [SI-303A(B) and SI-304A(B)) globe valves
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were replaced with A/D double disk gate valves; and the Safety injection Tank Drain Header to the RWSP Containment Isolation (Sl-343) globe i
valves were replaced with A/D double disk gate valves. Each of these replacements specified the use of a 0.5 valve factor in the sizing of the -
1 valve air operators.
In 1997, BD-102 A&B were replaced with new Anchor Darling air operated, parallel disc gate valves which were sized using a 0.5 valve factor in the safety direction (closed).
(d) There are other safety related air operated and hydraulically operated gate valves in the plant, excluding the new valves discussed above.
These are CVC-209, CS-125A(B), SI-405A(B), and MS-124A(B). CVC-209 is a locked open valve which is scheduled for modification in the next
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refueling outage. Because it is locked open, it has a passive safety function. CS-125A(B) are dynamically tested every outage to ensure proper functioning. They are in the AOV/HOV program scope, but not in the first phase of calculations under contract with ERIN. SI-405 was reviewed in EC-M91-076, "SI-405A(B) Actuator Thrust Calculation," in 1995. A valve factor of 0.5 was used in the thrust calculation, which will
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be increased to 0.6 based on MOV testing of a similar valve. Finally, Main Steam isolation Valves, MS-124A(B), are currently undergoing a design basis review by the engineering contractor to document their sizing capability.
(e) Design basis review calculations, which will incorporate MOV lessons learned, are in progress for over 100 air operated valves with the remainder of the valves to follow in relation to their safety significance.
'(f)
Design Engineering Procedure NOECP-011," Engineering Calculations,"
requires that a supplier performed calculation undergo a reasonableness review which includes a review of all calculation design inputs and assumptions. The procedure was recently revised to more clearly define a reasonableness review and the expectations associated with them.
The Engineer is required to sign a calculation cover sheet which documents that the design inputs and assumptions have been reviewed and approved. Had these changes been in place when the Anchor Darling evaluation was received, the valve factor assumption of 0.2 should have been questioned and revised accordingly. Therefore, with the revision of the Engineering Calculation Procedure, adequate measures have been taken to address the probable cause of the missed opportunity associated with the design change package review.
(g) The current process used by OEE for evaluation of ins involves several peer reviews and the OEE Manager review for issuance of the evaluation and associated recommendations. Additionally OEE solicits feedback
Attachmsnt to W3F1-98-0091 Page 8 of 8 from the responsible department and others regarding the accuracy and adequacy ofits reviews and recommendations. Waterford 3 considers this process and the barriers in place adequate.
ER-98-0507-00-00 has been issued by OEE to request the findings discussed in the IN from the EPRI MOV program be evaluated for their impact on other power-operated and manually-operated valves.
I t