ML20058C412
| ML20058C412 | |
| Person / Time | |
|---|---|
| Site: | River Bend  |
| Issue date: | 11/18/1993 |
| From: | Mcgaha J GULF STATES UTILITIES CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML20058C416 | List: |
| References | |
| RBEXEC-93-656, RBG-39425, NUDOCS 9312020449 | |
| Download: ML20058C412 (12) | |
Text
{{#Wiki_filter:4 4-GULF STATES UTILITIES COMPANY RIVE 4 BEND STATION
- 5485 U,S HIGHWAY 61 POST OFFICE BOX 220 S T.. F F4 A N C i S V I L t. E.
LOutStANA 70775 AREA CODE 504 635-6294 346-8651 P JOHN R. McGAllA, JR Vice (1csident - Rixr Bend Nuclear Group (501)3814371 Thr (bat) 3814872 i I November 18,1993 RBG-39425 File No. G9.5, G9.42 RBEXEC-93-656 ) i U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 River Bend Station - Unit 1 Docket No. 50-458 Gentlemen: Gulf States Utilities Company (GSU) hereby files an application to amend the River Bend Station - Unit 1 Technical Specifications. This application is filed to revise applicable Technical Specifications related to valve leak rate testing to allow a one-time extension of the sun'eillance intervals. Included in this request are administrative changes to the l Technical Specifications related to 10 CFR 50 Appendix J, Type C test intervals. These changes have been addressed by our request for exemption from the schedular . l requirements of 10 CFR 50, Appendix J submitted this date. The administrative changes l implement the extension to be granted based on that exemption request. The requested extensions are requested on a one-time only basis to support our current i refueling outage schedule. To require a plant shutdown solely to perform surveillance i tests would cause an unnecessary transient on the plant and result in unnecessary exposure to personnel. GSU will make a good faith effort to complete the surveillance tests within the current frequency if an outage of sufficient length occurs. Attachment I and Enclosures I and 2 to this letter provide the justification for the proposed revisions to the Technical Specifications as shown in Attachment 3. Attachment 2 provides the no significant hazards consideration discussion. j 9312O20449 931118 PDR ADOCK 05000458 P PDR f ./ I i
3 4 L-w Page 2 of 2 Ixtter to U. S. Nuclear Regulatory Conunission Document Control Desk i November 18,1993 RBG-39425 RBEXEC-93-656 i r If you have any questions or comments, please contact Mr. Ixif L. Dietrich of my staff at (504) 381-4866. Sincerely, N~ ohn IcGaha 1 Attachments i xc: U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, TX 76011 NRC Resident Inspector P.O. Box 1051 St. Francisville, LA 70775 Mr. Edward T. Baker U.S. Nuclear Regulatory Commission M/S OWFN 13-H-15 Washington, D.C. 20555 ' i Mr. Glenn Miller Radiation Protection Division I.ouisiana Department of Environmental Quality [ P.O. Box 14690 Baton Rouge, LA 70898 i 4 v i - j I I
l 1 UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION l STATE OF LOUISIANA ) PARISH OF WEST FELICIANA ) Docket No. 50-458 In the Matter of ) p GULF STATES UTILITIES COMPANY ) (River Band Station - Unit 1) ? AFFIDAVIT John R. McGaha Jr., being duly sworn, states that he is a Vice President of Gulf States Utilities Company; that he is authorized 1 on the part of said company to sign and file with the Nuclear Regulatory Commission the documents attached hereto; and that all such documents are true and correct to the best of his knowledge, i information and belief. John R. McGaha Jr. [ [ l Subscribed and sworn to before me, a Notary Public in and for the State and Parish above
- named, this
)T$4k day of % Qa h (LLA 1993. My Commission expires' with Life. J. kul Claudia F. Hurst Notary Public in and for West Feliciana Parish, Louisiana
~ Attached to: RBG 39425 J ATTACHMENT 1 GULF STATES UTILITIES COMPANY RIVER BEND STATION DOCKET 50-458/ LICENSE NO. NPF-47 VALVE LEAK RATE TESTING (93-11) DOCUMENT INVOLVED: Technical Specifications P ITEMS: Surveillance Requirement 4.4.3.2.2a Surveillance Requimment 4.6.1.3d Surveillance Requirement 4.6.1.3f REASON FOR REQUEST: The River Bend Station (RBS) Technical Specifications (TS) require, in several TS Surveillance Requirements (SRs), that valves providing isolation of Primary Containment that are scaled by the Main Steam - Positive Leakage Control System (MS-PLCS) or the Penetration Valve Leakage Contml System (PVLCS), and valves that provide isolation of the reactor coolant system from lower pressure rated systems (i.e., pressure isolation valves (PIVs)) be leak rate tested, nominally at refueling intervals but at least once every 18 months. TS 4.0.2 allows a 25% extension of the surveillance interval to 22.5 months, i if required, to provide Dexibility in cycle lengths. In addition to the above, valves providing isolation of Primary Containment are also required to be Type C leak rate tested in accordance with 10 CFR 50, Appendix J, Section III.D.3 at intervals not to exceed 24 months. The allowable extension of TS 4.0.2 does not apply to the intervals specified by 10 CFR 50, Appendix J, Section III.D.3. A one-time change is being requested to extend the surveillance intervals for the above cited TS SRs and, as applicable, to reflect our concurrent request for exemption fmm the i schedular requirements of 10 CFR 50, Appendix J, Section III.D.3. The TS SRs for which extension of the surveillance intervals is requested are a) SR 4.4.3.2.2a, Reactor Coolant System PIVs, and b) SR 4.6.1.3f, MS-PLCS and PVLCS sealing air leakage to containment. The TS. SR which is requested to reDect the exemption from the schedular requirements of 10 CFR 50, Appendix J is 4.6.1.3d, Type C tests. i GSU will make a good faith effort to conduct these surveillance tests on the current [ frequency if an outage of sufficient duration occurs. In order to perform the above suneillance tests, the plant umst be in a shutdown condition. To require the plant to shut i i l D k
1 1 4 Attached to: RBG-39425 down solely to perfonn surveillance tests would caue an unnecessary thermal transient on the plant and result in unnecessary exposure to personnel. GSU proposes to amend the cited TS contained in Appendix A to the RBS Operating License, as discussed below and in the respective enclosures, to perfonn the subject surveillance tests during the fifth refueling outage (RF-5), presently scheduled to begin April 16, 1994. The applicability of the extension should be until at least April 19, 1994, in order to allow time for cooldown to Mode 4 wherein the Limiting Conditions for Operation for the respective SRs are not applicable. Therefore, the proposed revisions to the TS are worded such that the surveillance tests 'may be performed during the refueling outage following the fifth' operating cycle scheduled to begin April 16, 1994'. Should the proposed changes not be granted by Febmary 7,1994, GSU will be forced to implement an unplanned outage during this operating cycle. BACKGROUND: i t The River Bend Station - Unit 1 (RBS) has been in operating Cycle 5 since September 8, 1992, after completing the fourth refueling outage which began March 12,1992. During this period, several forced outages have occurred which have impacted the 18-month surveillance intervals required by the TS for reactor coolant system PIV leak rate testing,. PVLCS and MS-PLCS leak rate testing, and the 24-month interval required by 10 CFR 50, Appendix J for valve leak rate testing. This will result in several surveillance tests. perfonned during the last refueling outage to exceed the surveillance interval plus the allowable extension to the interval specified in TS 4.0.2, where applicable. DISCUSSION: As stated in Section 5.2.5.1.4 of the RBS Updated Safety Analysis Report (USAR), safety systems connected to the reactor coolant pressure boundary (High Pressure Core Spray, Low Pressure Core Spray, Residual Heat Removal, and Reactor Core Isolation Cooling) are isolated from the reactor coolant system by two or more isolation valves placed in series. Periodic leak testing of each of these PIVs is perfonned to ensure the integrity of the valve, demonstrate the adequacy of the redundant pressure isolation function, and give indication of valve degradation over a period of time. In addition, the pressure in each of these systems is monitored. A high pressure alann, located in the main control room provides an indication of possible reactor coolant leakage into the system across the PIVs. Technical Specification SR 4.4.3.2.2a provides the leak testing requirement for each .} reactor coolant system PIV specified in TS Table 3.4.3.2-1. The valves are required to be demonstrated operable by leak testing pursuant to TS 4.0.5 [ASME Section -XI], .l including paragraph IWV-3427(B) of ASME Section XI and verifying that the leakage of each valve is within the specified limit at least once per 18 months (with a maximum allowable extension per TS 4.0.2 of 4.5 months). The cited PIVs from TS SR 4.4.3.2.2a require an extension of this surveillance interval in that 5 of the total 16 valves will exceed i 1 i i
+ j P L Attached to: RBG-39425 this interval duration by a maximum of 65 days. The justincation for this extension is provided in Enclosure 1. As cited in Section 6.2.4 of the RBS USAR, the purpose of the Containment Isolation System is to prevent the release of significant amounts of radioactive materials from the fuel, the reactor coolant pressum boundary, and the steel primary containment by automatically isolating appmpriate lines in the nuclear steam supply system, auxiliary systems, and suppon systems which penetrate the primary containment. As part of the Containment Isolation System, the MS-PLCS, per USAR Section 6.7, prevents the release of nssion products, in the event ofleakage, through the closed main steam isolation valves (MSIVs) and main steam drain lines after a design-basis loss of coolant accident (LOCA). The system establishes a pmssurized volume in the main steam lines by maintaining a pressure of at least 10 percent over the pmvailing post LOCA reactor vessel pmssure which could otherwise instigate leakage to the environment. In the same vein, per USAR Section 9.3.6, the purpose of the PVLCS is to control and minimize the release of Rssion pmducts which could leak through and from valves in lines penetrating the containment structure, which could potentially leak to the environment without prior processing by the standby gas treatment system or the charcoal filtmtion system of the fuel building ventilation system (bypass leakage). The PVLCS, similar to the MS-PLCS, uses air to pressurize valve bodies in various Guid systems that penetrate the containment by injecting air into the space between the seats of the double-disk gate valves. The pressure barrier is maintained at a pressure at least 10 percent higher than the peak calculated drywell pressure. Thus, for MS-PLCS and PVLCS sealed valves, only inleakage of nonradioactive air into the containment is possible l past the valves, and no post-LOCA containment atmosphere is discharged through the pressurized valves. Technical Specification SRs 4.6.1.3d,4.6.1.3f, and 4.6.1.3h specify the leak testing requirements for the valves which provide a containment isolation function. SR 4.6.1.3d requires that penetmtions and valves which provide a containment isolation function be Type C tested with gas at P, [ accident pressure), 7.6 psig, at intervals no e greater than 24 months. This SR implements the requirements of 10 CFR 50, Appendix l J. There are, however, exceptions to this SR, which include the containment isolation valves that are sealed with MS-PLCS and PVLCS (SR 4.6.1.3f). The valves that are sealed with MS-PLCS and PVLCS are required to be tested at 11.5 psid and 33 psid, respectively, to determine the sealing air leakage into primary containment. This SR is required to be conducted every 18 months. j Thiny-6ve (35) valves are sealed by MS-PLCS and PVLCS and are required to be tested i by TS SR 4.6.1.3f. Eleven (11) of these valves requim an extension of the surveillance interval for a maximum of 46' days. The justiGeation for this extension is provided in. l
L Attached to: RBG-39425 L The penetrations and valves requiring Type C testing pursuant to 10 CFR 50, Appendix J as addressed by TS SR 4.6.1.3d have been addressed by the request for exemption from the schedular requin ments of 10 CFR 50, Appendix J, Section III.D.3, which was submitted on this date under separate cover. Granting of the exemption will allow the TS SR 4.6.1.3d to be extended consistent with the exemption. i I REVISED TECHNICAL SPECIFICATIONS -l The requested revision to the Technical Specifications 4.4.3.2.2a,4.6.1.3d, and 4.6.1.3f f are shown on. This revision is a one-time only extension of the j surveillance intervals to allow the surveillance testing to be performed during the fifth refueling outage scheduled to begin April 16,1994. SCHEDULE FOR A'ITAINING COMPLIANCE As indicated above, RBS is currently in compliance with the applicable Technical l SpeciGcations. The Technical SpeciGcation revisions are required prior to February.7, t 1994, in order to avoid a unit outage to conduct the required surveillance tests as discussed herem. NOTIFICATION OF STATE PERSONNEL l A copy of this amendment request has been provided to the State of Louisiana, Depanment l of Environmental Quality - Radiation Protection Division. l ENVIRONMENTAL IMPACT APPRAISAL { GSU has reviewed the proposed license amendment request against the criteria of l 10 CFR 51.22 for categorical exclusion from envimnmental review. The proposed l changes to the Technical Specifications do not involve a significant hazards consideration, do not significantly change the types or significantly increase the amounts of efGuents which may be released offsite, and do not signiGcantly increase individual or cumulative l occupational exposure. Based on the foregoing, GSU concludes that the proposed change meets the criteria given in 10 CFR 51.22(c)(9) for categorical exclusion. from the requirement for environmental review. t I
-. ~. =. -- = Attached to: RBG-39425 ENCLOSURE 1 JUSTIFICATION FOR EXTENSION OF SURVEILLANCE REQUIREMENT l INTERVAL OF TECIINICAL SPECIFICATION 4.4.3.2.2a l RCS PRESSURE ISOLATION VALVE LEAK TESTING l The Reactor Coolant System Leakage, Operational Leakage TS SR 4.4.3.2.2a requims that the reactor coolant system (RCS) pressure isolation valves (PIVs) be tested once per 18 months (plus an allowable extension of 25 %). This testing involves a total of 16 valves. Five (5) of these valves require an extension of the surveillance interval for a maximum [ of 65 days. Technical Specification 3.4.3.2 provides for an allowable leak rate of 0.5 gpm per nominal inch of valve size, up to a maximum of 5 gpm per valve at a RCS pressum of 1025 15 i psig when tested pursuant to TS 4.0.5 and ASME Section XI, IWV-3427(B). Depending i on the valve sizes, the allowable leak mie per valve ranges from three (3) to five (5) gpm. i The as-found leakage exhibited by the 5 valves requiring extension, as measured dunng the last refueling outage, was 0.0048 gpm. Previously, during the third refueling outage,. .i these 5 valves exhibited an as-left leakage of approximately 0.332 gpm. This small 3 difference can probably be attributed to the diffemnce in the seating of the valves after l closure prior to testing. But the small measured leakage during both tests shows that the { valves am not subject to degradation over the 18-month period. In addition, at the last j refueling outage, only 5 of the total complement of PIVs exhibited any leakage, and the total as-left leakage was 0.385 gpm whien is well within the allowable leak rate. l. It should be further noted that NUREG-1463, " Regulatory Analysis for the Resolution of I Generic Safety Issue 105: Interfacing System less-of-Coolant Accident in Light Water Reactors" (July 1993), Section 2.5, "BWR Results" states: "An ISLOCA analysis was performed as part of the GI-105 research program and i is documented in NUREG/CR-5928. The work consisted of screening analyses and bounding calculations on the systems identified as potentially susceptible to an ISLOCA. A BWR/4 was examined,' and the following systems were explicitly j addressed: reactor core isolation cooling, high pressure coolant injection, core j spray, RHR, reactor water cleanup, and control rod drive. The study concluded [ that ISLOCA is not a risk concem." .} The above is applicable to RBS in that the design and accident response of a BWR/6 is j very similar to a BWR/4 for this issue. l l l
Attached to: RBG-39425 In addition, the River Bend Station Individual Plant Examination (IPE) (submitted to NRC by RBG-38,077 dated February 1,1993), Section 3.4.4.2 states: l "The chance of an ISLOCA causing a harsh operating environment for ECCS equipment was found to be negligibly small and the risk posed by an ISLOCA given a nonnal operating environment for ECCS equipment (and thus generic failure probabilities for ECCS) is very small." Based on a) the low as-found leak rate of the subject valves as measured during the last refueling outage, b) evidence from previous tests that the valves am not subject to degradation during the fuel cycle, c) the margin available fmm the previous as-left. leak rate test (0.385 gpm) and the TS allowed leakage (3 to 5 gpm per valve), and d) the conclusion of NUREG-1463 and the confinnation of the RBS PRA that the ISLOCA (which is the rationale for the PIVs in the system design) is not a risk concem for BWRs, the extension of the surveillance interval for 65 days is justified. l I i I i ? i i Y h
Attached to: RBG 39425 i ENCLOSURE 2 i JUSTIFICATION FOR EXTENSION OF SURVEILLANCE REQUIREMENT I INTERVAL OF TECHNICAL SPECIFICATION 4.6.1.3f l MS-PLCS AND PVLCS LEAKAGE INTO CONTAINMENT I Technical Specification SR 4.6.1.3f requires that the total sealing air leakage into ~ containment, at a test pressure of 11.5 psid for MS-PLCS valves and 33 psid for PVLCS valves, be detennined by test at least once per 18 months (plus an allowable extension of 25 %). Of the 35 valves which encompass this SR requirement, eleven (11) of the PVLCS . valves requim an extension in their surveillance interval for a maximum of 46 days. The valves requiring a surveillance interval extension constitute 31 % of the total number and do the Main Steam Isolation Valves (MSIVs) which were tested during a forced outage which occurred in the April to June 1993 period of this cycle. The valves which require an extension exhibited an as-found leak rate of 53.85 standard cubic feet per hour (scfh) during testing.at the last refueling outage. The as-left leak rate for these valves was 32.09 scfh. As cited in the River Bend Station Safety Evaluation Report, Supplement 2 (NUREG-0989), Section 6.2.1.3, analyses have detennined that a j constant 425 scfh of leakage from both the MS-PLCS and PVLCS sealed valves into containment is the maximum allowed to ensure a potential repressurization of containment is limited to less than 50 percent of containment design pressure during a 30 day period i following Loss of Coolant Accident. However, as stated in NUREG-0989, Supplement i 1, the TS 3.6.1.3c limit has been specified as 340 scfh, or 80% of the acceptable j inleakage. Following testing of the MSIVs during the aforementioned forced outage during this cycle, total leakage into containment on July 17,1993 (utilizing the as-left leak j rates detennined during the last refueling outage for valves not retested during the forced j outage) was detennined to be 75.15 scfh. Additionally, as stated in USAR Sections 6.7.2.2 and 9.3.6.3.2, if high flow from the MS-l PLCS or PVLCS or low pressure at the pressurized boundary in the main steam line or j the process line valves for PVLCS is detected, the systems will automatically isolate to prevent repressurization of containment. i Based on a) the low as-found and as-left leak rates for the valves requiring extension, b) low leakage detennined at this mid-cycle period, c) the fact that the major contributors (MSIVs) are not a part of the extension, d) the inherent 20% margin in the TS allowable leak rate value, and c) the system design which will isolate the MS-PLCS and PVLCS so that inleakage considerations can be maintained, the extension of 46 days for the surveillance interval for the remaining valves is justified. j t 1 j
l t Attached to: RBG-39425 l t 1 ATTACHMENT 2 'i i NO SIGNIFICANT HAZARDS CONSIDERATION t In accordance with the requirements of 10 CFR 50.92, the following discussion is pmvided in support of the detennination that no significant hazards are created or increased by the change requested in the submittal. l 1. The proposed change would not significantly increase the probability or consequences of an accident because: l The pmposed TS change requests a one-time only extension of the surveillance j intervals for the TS SR 4.4.3.2.2a, Reactor Coolant System Pressure Isolation l Valve (PIV) leak festing; and TS SR 4.6.1.3f, MS-PLCS and PVLCS sealed valves l leak rate testing, j Based on the discussion in the License Amendment Request which shows: a) the Reactor Coolant System Pressure Isolation Valves (PIVs) exhibited low as-found leak rates as measured during the last refueling outage; evidence from previous tests show that the valves are not subject to degradation during'the fuel l cycle; there is substantial margin available for the PIVs from the as-left leakage j (0.385 gpm) to the TS allowed leakage (3 to 5 gpm per valve, depending on valve i size); the interval extension required (65 days) is small when compared to the ovenil surveillance interval allowed by TS (22.5 months); and, the conclusion of l NUREG-1463 and the confinnation by the RBS IPE which cite the ISLOCA (for which PIVs are provided to prevent) is not a risk concem for BWRs; and i b) there is a limited number of MS-PLCS and PVLCS valves requiring interval extension (11 of a total of 35 valves), the valves requiring extension in their surveillance interval have previously had low as-found and as-left leak rates, there - is substantial margin frun the last mid-cycle determination of leakage. to l containment (75.15 scfh) to that allowed by TS (340 scfh), there is an inherent -{ 20% margin in the TS allowable leak rate value and the value shown to be acceptable by analysis, and the interval extension requested (46 days) is a small part of the ovemil interval allowed 1 y TS (2.2.5 months). i 7 Therefore, from the above it is shown that the proposed change will not f significantly increase the probability or consequences of an accident. In addition, the one-time extension of the surveillance interval for Type C tests is - j consistent with the exemption request filed this date and is considered to be j f l
l + Attached to: RBG-39425 administrative in nature. This fact, and the fact that extension to the surveillance interval is for a maximum of 35 days, provides assurance that the proposed change ] will not significantly increase the probability or consequences of an accident. 2. The proposed change would not create the possibility of a new or different kind of accident from any previously evaluated because The proposed TS change requests a one-time extension of the surveillance intervals j for the Reactor Coolant System Pressure Isolation Valve leak rate tests and the measurement of MS-PLCS and PVLCS valve sealing air inleakage to containment. In that the requested extension durations are small as compared to the overall interval allowed by TS, the low as-found and as-left leak rate values of the valves as measured during the last refueling outage, and the substantial margins available i from the last testing compared to the TS allowable values are substantial, the proposed change does not create the possibility of a new or different kind of accident from any accident previously analyzed. I In addition, the one-time entension of the surveillance interval for Type C tests is consistent with the exemption request filed this date and is considered to be j i administrative in nature. This fact, and the fact that extension to the surveillance interval is for a maximum of 35 days, provides assurance that the pmposed change 1 does not create the possibility of a new or different kind of accident from any accident previously analyzed. 3. The pmposed change will not involve a significant reduction in the margin of' safety because: 1 The proposed TS change requests a one-time extension of the surveillance intervals i for the Reactor Coolant System Pressure Isolation Valves leak tests and the measurement of the MS-PLCS and PVLCS sealing air inleakage to containment. In that the requested extension durations are limited, the low as found and as-left leak rate values of the valves as measured du.ing the last refueling outage, and the margins provided from the last testing compared to the TS allowable values are substantial, the proposed change does not involve a significant reduction in the i margin of safety. i In addition, the one-time extension of the surveillance interval for Type C tests is I consistent with the exemption request filed this date and is considered to be administrative in nature. This fact, and the fact that extension to the surveillance' interval is for a maximum of 35 days, provides assurance that the proposed change does not provide a significant reduction in the margin of safety. i 5 -i 1 - -}}