ML20141G485
| ML20141G485 | |
| Person / Time | |
|---|---|
| Site: | Waterford  |
| Issue date: | 05/20/1997 |
| From: | NRC (Affiliation Not Assigned) |
| To: | |
| Shared Package | |
| ML20141G483 | List: |
| References | |
| NUDOCS 9705220373 | |
| Download: ML20141G485 (5) | |
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NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20666 4 001 p%...../
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION REMT.EQ TO AMENDMENT NO.128 TO FACILITY 0PERATING LICENSE NO. NPF-38 i
ENTERGY OPERATIONS. INC.
WATERFORD STEAM ELECTRIC STATION. UNIT 3 DOCKET NO. 50-382
1.0 INTRODUCTION
By application dated August 21, 1996, as supplemented by letter dated March 17, 1997, Entergy Operations, Inc. (the licensee), submitted a request for changes to the License No. NPF-38 issued for Waterford Steam Electric j
Station, Unit 3 (Waterford 3). The requested changes involve the design and testing modifications at Waterford 3.
These modifications require the Nuclear Regulatory Commission (NRC) staff approval for the adequacy of both the l
containment isolation arrangement and the Type C leak testing of the barriers of two instrument sensing lines at Waterford 3.
These lines are in the Containment Vacuum Relief System (CVR) that penetrate the primary containment.
The penetrations are commonly referred to as Penetrations 53 and 65. These modifications were found necessary because it was discovered that the current i
plant configuration did not agree with information provided to the NRC staff during the licensing process for Waterford 3.
In addition the licensee proposed to revise a License Condition (Attachment 1) to the Operating License No. NPF-38 for Waterford 3 to reflect the modifications in Penetration 53 and 65.
The March 17, 1997, letter provided additional information that did not change the initial proposed no siginficant hazards consideration determination.
2.0 DISCUSSION AND EVALUATION During the licensing process for Waterford 3, the staff requested additional information concerning the isolation arrangements and testing commitments for Penetrations 53 and 65 at Waterford 3.
The licensee's response described the arrangement by indicating that penetrations 53 and 65 each contain two instrument lines. One is considered i
an essential line sensing differential pressure across the containment vessel and provides a signal to actuate the vacuum relief system, the other monitors this differential pressure and provides en input to the plant computer. This 1
other signal is considered to be non-essential. Whether or not the line is essential is important since the isolation requirements differ between essential and non-essential lines.
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The response indicated that the essential line contains an excess flow check valve. The non-essential line also contains an excess flow check valve but a commitment was made to also add a solenoid operated valve during the first refueling outage. This added valve would be automatically closed on a containment isolation signal. This commitment to add the solenoid valves was included as a license condition in the Waterford 3 license.
In addition to the excess flow check valves and the solenoid valves, the licensee indicated that both lines formed a closed system outside containment, are seismically qualified, and terminate in an area exhausted by the filters of the Controlled Ventilation Area System.
Based on this information, the staff concluded that the closed system was an acceptable barrier.
Therefore, the essential line was assumed to have two barriers; the excess flow check valve and the closed system. The non-essential line also had the same two barriers and a third barrier would be added during the first refueling outage. This barrier would be a solenoid operated automatic valve.
The licensee further indicated that with the above isolation arrangements for both lines, Type C leak testing was not required to be performed. The NRC in the Waterford 3 SER accepted the design configuration and testing requirements for the CVR instrument lines in penetrations 53 and 65. The commitment to install the solenoid valves was satisfied on January 19, 1987, however, the license condition was not removed.
The above situation continued until it was discovered by'the licensee that the conditions for a closed system were not consistent with the as builc i
situation. This required a reassessment of both the isolation arrangements as well as the testing requirements for both penetrations.
The reassessment separated the essential and non-easantial lines, since the requirements are different. The discussion will begin with the essential lines in penetrations 53 and 65.
The essential lines do qualify for the criteria of Regulatory Guide (RG) 1.141. The significance of this criteria is to not require automatic containment isolation. The next criteria that was identified as applicable was General Design Criterion (GDC) 56. This GDC addresses the isolation requirements of penetrations that are connected to the containment.
Generally, this GDC requires specific isolation valve types that would be acceptable as containment isolation barriers. However, instrument lines that are considered to be vital or essential to the overall safety of the power plant have further relaxations. Excess flow check valves, for example, are normally not considered as acceptable containment isolation ' barriers.
However, GDC 56/57 allow specific relaxations for signals that are considered to be important enough that interruption of the signal represents a reduction to the plant safety.
This line class is identified as essential.
This consideration allowed the use of an excess flow check valve as an acceptable containment isolation barrier. The next consideration was the determination of whether or not the system represented a closed system beyond the excess flow check valve. Normally, the system should be designed in accordance with Quality Group B standards as defined by RG 1.26.
This means ASME Section III, Class 2.
However, instrument lines are not covered by RG 1.26.
Therefore, the licensee criteria classified there lines as ISA-67.02. The licensee considered that this classification was consistent with the endorsement by the NRC.
The staff agrees that the above criteria is consistent with the requirements of Quality Group C (i.e., A5Mr,Section III, Class 3) which is consistent with the staff's interpretation of the criteria governing instrument lines. The staff conclusion is that tSe design meets all of the criteria of a closed system. Therefore, the staff concurs that the system is a closed system.
The staff concludes that the existing containment isolation provisions of the essential lines of penetrations 53 and 65 are acceptab h without any hardware modifications.
Consideration of the non-essential lines is significantly different from the essential lines.
Each line has a solenoid globe valve that will automatically close on a containment isolation signal. However, the second containment isolation barrier was in question. The remaining tubing beyond the solenoid valve is non-safety.
In addition, the monitoring lit:es downstream of the isolation valves are not classified as seismic Category I.
These combined variations cause the staff to conclude that a closed system is not present and therefore, the existing hardware arrangement does not meet the containment isolation requirements.
An important consideration is the acceptability of the excess flow check valve as a containment isolation barrier. The staff concludes that this barrier is unacceptable since it does not meet the criteria of RG 1.11.
The acceptably of this type of barrier can only be justified for the essential signals.
In order to comply with the criteria of Safety Guide 11, one must be able to sh0w that the importance of the line signal is safety significant.
For a non-safety line, this condition cannot be met. The relaxation of the use of an excess flow check valve as an acceptable barrier is therefore unacceptable.
Therefore, an acceptable barrier in addition to the solenoid automatic valve 1s required.
The licensee recognized this limitation and proposed an additional valve.
The licensee proposes to add a second solenoid automatic valve. This is acceptable to the staff.
There were two penetrations for the non-safety function.
The licensee proposes that one of the lines be closed via closing the penetration with seal welding.
For.the other penetration, the license will add the automatic solenoid valve from the seal closed line as the second valve meeting the acceptance criteria of GDC 56.
Based on the above, the staff finds the isolation criteria of penetrations 53 and 65 acceptable.
For the essential sensing instrument lines, the licensee indicated that the lines will be pressurized and leak tested at refueling intervals. This satisfies the testing of the closed system. The testing pressure will be 48
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psig and the measured leakage will be added to the bypass leakage total.
In addition, in light of the failures of the excess flow check valves, functional testing will be performed at refueling intervals.
j For tne non-essential lines, the licensee has indicated that local leak rate f
testing (LLRT) and inservice testing (IST) program testing will be performed i
on both automatic solenoid containment isolation valves.
LLRT means Type.C
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testing under the Appendix J program.
Based on the above information, the staff finds that the testing requirements have been satisff 9d and, therefore, are acceptable for both the essential and non-essential instrument lines in penetrations 53 and 65.
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The licensee proposed to revise a License Condition (Attachment 1 to the License) to reflect the proposed changes. The proposed changes in the License Condition are acceptable to the staff.
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l Based on the above findings, the staff finds the proposed modifications to the lines in penetrations 53 and 65 acceptable.
In addition, the testing criteria proposed for the barriers are also acceptable. The proposed changes in the License Condition are also acceptable.
3.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Louisiana State official was notified of the proposed issuance of the amendment. The State official had no comments.
4.0 ENVIRONMENTAL CONSIDERATION
l The amendment changes a requirement with respect to installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 and changes surveillance requirements. The NRC staff has determined that the amendment involves no significant increase in the amounts, and no 4
significant change in the types, of any effluents that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously issued a pro-posed finding that the amendment involves no significant hazards consideration and there has been no public comment on such finding (61 FR 57484),
Accordingly, the amendment meets the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9).
Pursuant to 10 CFR 51.22(b) no environmental impact statement or environmental assessment need be prepared in connection with the issuance of the amendment.
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>., 5.0 @NCLUSION The Commission has concluded, based on the considerations discussed above, thrt:
(1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendment will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor:
J. Kudrick Date:
May 20, 1997
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