ET 05-0007, Request for Approval of Changes to the Reactor Coolant System Leakage Detection Instrumentation Methodology

Request for Approval of Changes to the Reactor Coolant System Leakage Detection Instrumentation Methodology

ML052510236
Person / Time
Site:	Wolf Creek
Issue date:	08/26/2005
From:	Garrett T Wolf Creek
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
+kBR1SISP20060306, ET 05-0007
Download: ML052510236 (28)

Text

'NUCLEAR OPERATING CORPORATION Terry J. Garrett Vice President Engineering August 26, 2005 ET 05-0007 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

Subject:

Docket No. 50-482: Request for Approval of Changes to the Reactor Coolant System Leakage Detection Instrumentation Methodology.

Gentlemen:

Wolf Creek Nuclear Operating Corporation (WCNOC) herewith transmits a request for approval of a change to Reactor Coolant System (RCS) leak detection instrumentation methodology employed for the Wolf Creek Generating Station (WCGS). This change was evaluated under 10 CFR 50.59 and it was concluded, pursuant to criterion viii of 10 CFR 50.59(c)(2), that the activity may be construed to be a departure from a method of evaluation described in the Updated Safety Analysis Report (USAR) that was used to establish the design bases or in the safety analyses for the facility.

This proposed amendment to the Wolf. Creek Generating Station (WCGS) license is being submitted per the guidance provided in -10 CFR 50.59(c). Implementation of the proposed change requires revising the Bases for TS 3.4.13, 'RCS Operational LEAKAGE," Bases for Technical Specification (TS) 3.4.15, "RCS Leakage Detection Instrumentation," USAR Appendix 3A, Section 5.2.5.2.3 and Table 5.2-6. This change would clarify the requirements of the containment atmosphere gaseous radioactivity monitor with regard to its RCS leak detection capability and provide clarification that the monitor can be considered OPERABLE (in compliance with TS Limiting Condition for Operation (LCO) 3.4.15) during' all applicable MODES even when reactor coolant radioactivity levels are below the levels assumed in the original licensing basis for WCGS.

Attachments I through IV provide the Evaluation, Markup of Technical Specification (TS) Bases, Markup of USAR, and Summary of Regulatory Commitments, respectively, in support of this amendment request. Final TS Bases changes will be implemented pursuant to TS 5.5.14, "Technical Specification Bases Control Program," at the time the amendment is implemented.

P.O. Box 411/ Burlington, KS 66839 Phone: (620) 364-8831 An Equal Opportunity Employer M/F/HCNIET

ET 05-0007 Page 2 It has been determined that this amendment application does not involve a significant hazard consideration as determined per 10 CFR 50.92. Pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the issuance of this amendment. The WCNOC Plant Safety Review Committee and the Nuclear Safety Review Committee have reviewed and approved the attached licensing evaluations and have approved the submittal of this amendment application. WCNOC requests approval of this proposed License Amendment by March 2006. The amendment will be implemented within 90 days after NRC approval. In accordance with 10 CFR 50.91, a copy of this amendment application is being provided to the designated Kansas State official.

If you have any questions concerning this matter, please contact me at (620) 364-4084, or Mr.

Kevin Moles at (620) 364-4126.

Very truly yours, Terry J. Garrett TJG/rlg Attachments: Evaluation I1 Markup of Technical Specification Bases Ill Markup of USAR IV Summary of Regulatory Commitments cc: J. N. Donohew (NRC), w/a W. B. Jones (NRC), w/a B. S. Mallett (NRC), w/a Senior Resident Inspector (NRC), w/a

STATE OF KANSAS

) SS COUNTY OF COFFEY Terry J. Garrett, of lawful age, being first duly sworn upon oath says that he is Vice President Engineering of Wolf Creek Nuclear Operating Corporation; that he has read the foregoing document and knows the contents thereof; that he has executed the same for and on behalf of said Corporation with full power and authority to do so; and that the facts therein stated are true and correct to the best of his knowledge, information and belief.

By (f, Terry. Garrett VicdPresident Engineering SUBSCRIBED and sworn to before me this c2 / day of lT)ay, 2005.

__IStraw cJ'J-it 1 1/2o 7 RHONDALGEj Notary Public SIIWEZV ,n .,

l//?U 14c A,

Expiration Date 2

Attachment I to ET 05-0007 Page1 of 10 EVALUATION

1.0 DESCRIPTION

The proposed change would revise the Bases for TS 3.4.13, uRCS Operational LEAKAGE," the Bases for Technical Specification (TS) 3.4.15, "RCS Leakage Detection Instrumentation," and Updated Safety Analysis Report (USAR) Appendix 3A, Section 5.2.5.2.3 and Table 5.2-6 (Reference 7.3) to clarify the design and OPERABILITY requirements of the containment atmosphere gaseous radioactivity monitor as a method of Reactor Coolant System (RCS) leak detection. Table 5.2-6 is revised to identify the capabilities and limitations of the containment atmosphere gaseous radioactivity monitors at low RCS activity levels.

Evaluations have shown that the pre-existing containment radioactive gaseous background levels for which reliable detection is possible is dependent upon reactor power level, percent failed fuel, and containment purge operation. With primary coolant concentrations less than background equilibrium levels, such as during startup and operation with no fuel defects, the increase in detector count rate due to leakage will be partially masked by the statistical variation of the minimum detector background count rate, rendering reliable detection of a 1 gpm leak in one hour uncertain.

Operating experience has shown gaseous background radiation levels at the Wolf Creek Generating Station (WCGS) would partially mask the detection of a 1 gpm leak. However, the monitor is capable of detecting an RCS to containment atmosphere leak if elevated reactor coolant gaseous activity is present above the background equilibrium levels.

This change was evaluated under 10 CFR 50.59 and it was concluded, pursuant to criterion viii of 10 CFR 50.59(c)(2), that the activity may be construed to be a departure from a method of evaluation described in the USAR that was used to establish the design bases or in the safety analyses for the facility. This method of evaluation is described in USAR Section 5.2.5.2.3, "Component Operation," for the containment atmosphere gaseous radioactivity monitor.

However, based on the RCS activity being lower than the primary coolant radioactivity concentration assumption in Regulatory Guide 1.45, the results of the current method of evaluation are non-conservative since a one gpm leak cannot be reliably detected in one hour.

The proposed use of the containment atmosphere gaseous radioactivity monitor with low RCS activity levels (based on continuous fuel improvements) is construed to be a departure from a method of evaluation described in the USAR used in establishing the design bases or in the safety analyses.

2.0 PROPOSED CHANGE

S The proposed changes would clarify the design and OPERABILITY requirements of the containment atmosphere gaseous radioactivity monitor as a method for RCS leakage detection as described in TS 3.4.15 and 3.4.13 Bases and USAR Section 5.2.5 and Appendix 3A. Table 5.2-6 is revised to indicate that containment atmosphere gaseous radioactivity monitors provide reliable leak detection capabilities provided that the equilibrium activity of the containment atmosphere is below the level that would mask the change in activity corresponding to a 1 gpm leak in one hour. All of the changes are more specifically described as follows.

Attachment I to ET 05-0007 Page&2 of 10 The following changes are proposed to the Bases for TS 3.4.13:*

Bases for TS 3.4.13, SR 3.4.13.1 are revised to indicate that early detection of pressure boundary LEAKAGE or unidentified LEAKAGE is provided by systems that monitor containment atmosphere particulate radioactivity and containment sump level.

The following changes are proposed to the Bases for TS 3.4.15:

Bases for TS 3.4.15, BACKGROUND, are revised to separate the discussion of the containment atmospheric particulate radioactivity monitor and the containment atmosphere gaseous radioactivity monitor as a method for RCS leakage detection. In addition, text is added to discuss the limitations of the containment atmosphere gaseous radioactivity monitor as a method for RCS leakage detection with low levels of radioactivity in the RCS.

Bases for TS 3.4.15, LCO, are revised to include additional text discussing the OPERABILITY requirements for the containment atmosphere gaseous radioactivity monitor.

In particular, this section will be revised to state that, given the limitations of the monitor at low reactor coolant radioactivity levels, OPERABILITY of the gaseous radioactivity monitors is based on the monitor's ability to meet the required surveillances and not on its ability to indicate 1 gpm RCS boundary leakage in one hour.

The following changes are proposed to the USAR:

Appendix 3A is revised to indicate an exception to Regulatory Guide 1.45 (Reference 7.2),

"Reactor Coolant Pressure Boundary Leakage" as specified in Table 5.2-6.

USAR Section 5.2.5.2.3 is revised to include additional discussion on the limitations on the use of the containment atmosphere gaseous radioactivity monitor as a method of RCS leakage detection.

USAR Table 5.2-6, item 5, is revised to include text identifying the capabilities of the containment atmosphere radioactivity monitor for meeting the requirements of Position C.5 of Regulatory Guide 1.45.

Attachments 2 and 3 provide the TS Bases and USAR markups, respectively, in support of this amendment request. Final TS Bases changes will be implemented pursuant to TS 5.5.14,

'Technical Specification Bases Control Program," at the time the amendment is implemented.

3.0 BACKGROUND

On November 9,2004, the WCGS-Nuclear Regulatory Commission (NRC) Integrated Inspection Report 05000482/2004004 issued noncited violation (NCV)05000482/2004004-001 for failure to identify and correct a significant condition adverse to quality. In the report the NRC stated that the licensee failed to recognize that the containment atmosphere gaseous radioactivity monitors were inoperable. This issue had been previously entered into and evaluated under our corrective action program (Performance Improvement Request (PIR) 2003-1038). That evaluation determined that the containment atmosphere gaseous

Attachment I to ET 05-0007 Page 3 of 10 radioactivity monitors meet the design and licensing basis requirements in accordance with Regulatory Guide 1.45, "Reactor Coolant Pressure Boundary Leakage Detection Systems," as documented in the WCGS USAR. On November 17, 2004, WCNOC conservatively declared the containment atmosphere gaseous radioactivity monitors inoperable for meeting LCO 3.4.15, pending resolution of this issue. Declaring the gaseous radioactivity monitors inoperable was based on the regulatory concern identified in the inspection report and ensuring compliance with LCO 3.4.15. The monitors were designed consistent with the guidance of Regulatory Guide 1.45 for having a sensitivity. capable of detecting a 1 gpm leak in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> based on a primary coolant radioactivity concentration assumption utilized in the plant environmental report.

The monitors are fully functioning in accordance with specified design requirements and are meeting the current TS surveillance requirements. Approval of this proposed amendment will clarify the design and OPERABILITY requirements for the containment atmosphere gaseous radioactivity monitor as a method of RCS leak detection, and that the monitor may still be regarded as OPERABLE during all applicable MODES, even when reactor coolant radioactivity levels are low, as long as the monitor otherwise meets Regulatory Guide 1.45 requirements (for detector sensitivity, etc.) and can meet their Surveillance Requirements. This change is based on a change to the methodology described in Regulatory Guide 1.45 as effected through appropriate change to the USAR.

Leak Detection System Design The diverse reactor coolant pressure boundary leakage detection system consists of the containment sump level and flow monitoring system, the containment air particulate monitoring system, the containment radioactive gas monitoring system, and the containment cooler condensate measuring system. The sump level and flow monitoring system'indicates leakage by monitoring increases in sump level. The containment cooler condensate measuring system detects leakage from the release of steam or water to the containment atmosphere. The air particulate and 'radioactive gas monitoring systems detect leakage from the release of radioactive materials to the containment atmosphere. OPERABILITY requirements for these systems are specified in the plant TSs. Each of these systems is described in further detail below.

In addition to the above systems, the containment humidity measuring system is also available as an indirect indication of leakage to the containment. Further, reactor coolant pressure boundary leakage can also be indicated by increasing charging pump flow rate compared with reactor coolant system inventory changes and by unscheduled increases in reactor makeup water usage.

CONTAINMENT SUMP LEVEL AND FLOW MONITORING SYSTEM - Since a leak in the primary system would result in reactor coolant flowing into the containment normal or instrument tunnel sumps, leakage would be indicated by a level increase in the sumps.

Indication of increasing sump level is transmitted from the sump to the control room level indicator by means of a sump level transmitter. The system provides measurements of low leakages by monitoring level increase versus time. A sensitivity of 1 gpm in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> can be achieved assuming that the water from the leak is collected in the sump.

The minimum detectable change in the containment normal sump level is 3 gallons and in the instrument tunnel sump level is 15 gallons. When the instrument tunnel sump is completely dry, the minimum detectable level change is 25 gallons. The levels are scanned by the Balance

Attac.hment I to ET 05-0007 Page4of 10 of Plant (BOP) computer once per minute, and the normal background rate of increase in sump level is subtracted to determine the leakage rate. The actual reactor coolant leakage rate can be established from the increase above the normal rate of change of sump level after consideration of 35 percent of the high temperature leakage which initially evaporates but may be condensed by the containment coolers and then is routed to the sump. A check of other instrumentation would be required to eliminate possible leakage from nonradioactive systems as a cause of an increase in sump level.

CONTAINMENT AIR PARTICULATE MONITOR - An air sample is drawn outside the containment into a closed system by a sample pump and is then consecutively passed through a particulate filter with detector, an iodine filter with detector, and a gaseous monitor chamber with detector. The particulate monitor has a range of 10.12 to 1077pCi/cc and a minimum detectable concentration of 10 "pCi/cc.

Particulate activity is determined from the containment free volume and the coolant fission and corrosion product particulate activity concentrations. Any increase of more than two standard deviations above the count rate for background would indicate a possible leak. The total particulate activity concentration above background, due to an abnormal leak and natural decay, increases almost linearly with time for the first several hours after the beginning of a leak. With 0.1-percent failed fuel, containment background airborne particulate radioactivity equivalent to 104 percent/day, and a partition factor equal to 0.2, a 1-gpm leak would be detected in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

CONTAINMENT COOLER CONDENSATE MONITORING SYSTEM - The condensate monitoring system permits measurements of the liquid runoff from the containment cooler units.

It consists of a containment cooler drain collection header, a vertical standpipe, valving, and standpipe level instrumentation for each cooler.

The condensate flow rate is a function of containment humidity, essential service water temperature leaving the coolers, and containment purge rate. The water vapor dispersed by a I gpm leak is much greater than the water vapor brought in with the outside air. Air brought in from the outside is heated to 500 F before it enters the containment.

After the air enters the containment, it is heated to 100-1200 F so that the relative humidity drops. The water vapor brought in with the outside air does not build up in the containment.

Level changes of as little as 0.25 inches in the cooler condensate standpipes can be detected.

Increases in the condensation rates over normal background are monitored by the BOP computer based upon level checks each minute in order to determine the unidentified leakage.

A sensitivity of 1 gpm in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> can be achieved with cold essential service water temperature to the containment coolers or with initial background leakage.

CONTAINMENT GASEOUS RADIOACTIVITY MONITOR - The containment gaseous radioactivity monitor determines gaseous radioactivity in the containment by monitoring continuous air samples from the containment atmosphere. After passing through the gas monitor, the sample is returned via the closed system to the containment atmosphere. Each sample is continuously mixed in a fixed, shielded volume where its activity is monitored. The monitor has a range of 10'7 to 10 2pCi/cc and a minimum detectable concentration of 2 x 10 7 pCi/cc.

Attachment I to ET 05-0007 Page 5 of 10 Gaseous radioactivity is determined from the containment free volume and the gaseous activity concentration of the reactor coolant. Any increase more than two standard deviations aboye the count rate for background would indicate a possible leak. The total gaseous activity level above background (after 1 year of normal operation) increases almost linearly for the first several hours after the beginning of the leak. With 0.1-percent failed fuel, containment background airborne gaseous radioactivity equivalent to 1 percent/day, and a partition factor equal to 1 (NUREG-0017 assumptions),.a 1-gpm leak would be detected within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Need for the Amendment Although the detection capabilities of the containment gaseous radioactivity monitor are consistent with its design basis, the level of radioactivity in the reactor coolant at WCGS has become much lower than what is assumed in the USAR analysis. As such, the containment atmosphere gaseous radioactivity monitors will not respond within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> to a 1 gpm leak with low RCS activity levels.

Approval of this, proposed amendment would clarify the design and OPERABILITY requirements for the containment atmosphere gaseous radioactivity monitor as an acceptable method of RCS leak detection.

4.0 TECHNICAL ANALYSIS

RCS leakage detection requirements are given in TS 3.4.15 which requires the following RCS leakage detection instrumentation to be OPERABLE:

a. The containment sump level and flow monitoring system;

b. One containment atmosphere particulate radioactive monitor; and

c. The containment cooler condensate monitoring system or one containment atmosphere gaseous radioactivity monitor.

The Bases for TS 3.4.15 state that GDC 30 of Appendix A to 10 CFR 50 requires means for detecting and, to the extent practical, identifying the location of the source of RCS LEAKAGE.

Regulatory Guide 1.45 describes acceptable methods for selecting leakage detection systems.

In addition the Bases discusses that leakage detection systems must have the capability to detect significant reactor coolant pressure boundary (RCPB) degradation as soon after occurrence as practical to minimize the potential for propagation to a gross failure.

NUREG-0881, uSafety Evaluation Report Related to the Operation of Wolf Creek, Unit 1,"

Section 5.2.5, "RCPB Leakage Detection,". refers to NUREG-0830. In NUREG-0830, "Safety Evaluation Report related to the operation of Callaway Plant, Unit No. 1," Section 5.2.5, the NRC acknowledged that the installed RCS leakage detection systems are in compliance with the guidance found in Regulatory Guide 1.45 such that leakage of one gpm in one hour can be detected, satisfy the criteria of GDC 30, and are therefore acceptable. This criterion continues to be met by the diverse RCS leakage detection system consisting of the containment sump level and flow monitoring system, the containment air particulate radioactivity monitor, the containment cooler condensate monitoring system and the containment atmosphere gaseous radioactivity monitor under certain operating conditions.

Attachment I to ET 05-0007 Page 6 of 10 The detection of RCS leakage using radiation monitors is affected by the type and quantity of isotopes that are contained in the reactor coolant and the background level of radiation affecting/influencing the detectors. Regulatory Guide 1.45 guidance on analyzing the sensitivity of radiation monitors used for RCS leakage detection recommends that a realistic primary coolant radioactivity concentration assumption be used. The Regulatory Guide further defines the realistic primary coolant concentration as the values used in the plant environmental report.

For WCGS these concentration values are based on a 0.12% fuel defect from the WCGS Environmental Report - Operating Licensing Stage (Reference 7.4). With the level of radioactivity in the reactor coolant assumed in the WCGS Environmental Report - Operating Licensing Stage, the containment atmosphere particulate and gaseous radioactivity detectors are capable of detecting a one gpm leak in one hour. However, operational history of the plant has shown the level of radioactivity in the reactor coolant with no fuel defects is much lower than what is assumed in the USAR. The regulatory guide acknowledges the limitations of radiation monitoring for leak detection when the RCS activity is low. Further, the regulatory guide recommends a sensitivity of 1 x 106 for gaseous radioactivity monitors used for leak detection. The existing containment atmosphere gaseous radioactivity channel has a sensitivity of 2 x 10'7 and a range of 10-7 to 10.2 pCi/cc, which meets the criteria specified in Regulatory Guide 1.45.

Given the level of radioactivity in the reactor coolant at WCGS with no or minor fuel cladding defects, evaluation has shown that the containment atmosphere gaseous radioactivity monitors would not promptly detect a one gpm leak in one hour. This conclusion is based on a realistic nominal detector background level, with the typical RCS gaseous activity associated with no fuel cladding defects. For these lower RCS activity levels, the increase in detector count rate due to leakage will be partially masked by 1) the statistical variation of the minimum detector background count rate, and 2) the Ar-41 activation activity rendering reliable detection of a 1 gpm leak in one hour uncertain. At elevated RCS activity/failed fuel conditions as discussed in Regulatory Guide 1.45, a one gpm leak would be detectable within one hour, even at higher detector background.

Regulatory Guide 1.45, Section B, discusses the selection of diverse leak detection methods given that the methods differ in sensitivity and response time. Prudent selection of detection methods should include sufficient systems to assure effective monitoring during periods when some detection systems may be ineffective or inoperable. The Bases for TS 3.4.15 thus state, This LCO is satisfied when diverse monitoring methods are available."

Impact on Leak Before Break Analysis for WCGS In light of the RCS leakage detection capabilities of the containment atmosphere gaseous radioactivity monitors described above, the technical bases for applying leak-before-break (LBB) analyses to WCGS is still valid due to the selection of diverse leak detection methods.

The LBB approach is the application of fracture mechanics technology to demonstrate that high energy piping is very unlikely to experience catastrophic ruptures or failures. The NRC LBB guidance is provided in NUREG-1061, "Report of the U.S. Nuclear Regulatory Commission Piping Review Committee," Volume 3 (Ref. 7.1), "Evaluation of Potential for Pipe Breaks,"

requires the following criteria to be satisfied: 1) the leakage flaw size should be large enough so that the leakage is assured of detection with at least a margin of 10 using the minimum installed leak detection capability when the pipe is subjected to normal operational loads; 2) under normal plus safe shutdown earthquake (SSE) loads there should be a margin of 2.0 between

Attachment I to ET 05-0007 Page7of 10 the leakage size flaw and the critical-size flaw which could propagate to piping failure to account for the uncertainties inherent in the analyses and the leakage detection capability; arnd

3) flaw stability must be demonstrated. In addition, NUREG-1061, Volume 3, specifies that the RCS leakage detection capability should meet the criteria established in Regulatory Guide 1.45.

As stated in NUREG-1061, Volume 3, licensees and applicants have the option of requesting a decrease in leakage margin provided they could confirm that their leakage detection systems are sufficiently reliable, redundant, diverse, and sensitive. The basis for the NRC's approval of previous LBB analysis for WCGS continues to be supported by the overall RCS leakage detection capability of the diverse methods described in Section 3.0 above.

Conclusion In summary, the proposed amendment will clarify the design and OPERABILITY requirements of the containment atmosphere gaseous radioactivity monitor as a method of RCS leak detection and identifies the specific exception to position C.5 of Regulatory Guide 1.45 for this method of RCS leak detection. In addition, this change will add wording to the LCO Bases for TS 3.4.15 and 3.4.13 to make OPERABILITY of the containment atmosphere gaseous radioactivity monitor dependent on meeting the sensitivity and other requirements of Regulatory Guide 1.45 and not dependent on being capable of detecting a 1 gpm leak in one hour. The proposed amendment continues to require diverse methods of RCS leakage detection, to satisfy the intent of Regulatory Guide 1.45, with the capability to detect and measure RCS leakage with sufficient degree of accuracy to support the technical basis for WCGS.

5.0 REGULATORY ANALYSIS

5.1 NO SIGNIFICANT HAZARDS CONSIDERATION The proposed change would revise TS 3.4.13 and 3.4.15 Bases and-Updated Safety Analysis Report (USAR) Section 5.2.5 and Appendix 3A to clarify the design and OPERABILITY requirements of the containment atmosphere gaseous radioactivity monitor as a method of Reactor Coolant System (RCS) leak detection. Table 5.2-6 is revised to indicate that containment atmosphere gaseous radioactivity monitors provide reliable leak detection capabilities provided that the equilibrium activity of the containment atmosphere is below the level that would mask the change in activity corresponding to a 1 gpm leak in one hour.

The WCGS RCS leakage detection instrumentation continues to provide a diverse means of promptly detecting an RCS leak. The proposed amendment clarifies the design and OPERABILITY requirements and identifies the capabilities of the containment atmosphere gaseous radioactivity monitors at low RCS activity levels for satisfying the intent of Regulatory Guide 1.45, by requiring diverse means of leakage detection equipment with capability to promptly detect RCS leakage consistent with the technical basis in the leak-before-break analysis for WCGS.

The proposed change does not involve a significant hazards consideration for WCGS based on the three standards set forth in 10 CFR 50.92(c) as discussed below:

Attachment I to ET 05-0007 Page 8 of 10 (1) The proposed change does not involve a significant increase in the probability or consequences of an accident previously evaluated.

The proposed change has been evaluated and determined to not increase the probability or consequences of an accident previously evaluated. The proposed change does not make any hardware changes and does not alter the configuration of any plant system, structure, or component (SSC). The proposed change only clarifies the design and OPERABILITY requirements for the containment atmosphere gaseous radioactivity monitors and identifies the capabilities of the monitors at low RCS activity levels. The containment atmosphere gaseous radioactivity monitors are not initiators of any accident; therefore, the probability of occurrence of an accident is not increased. The USAR and TSs will continue to require diverse means of leakage detection equipment, thus ensuring that leakage due to cracks would continue to be identified prior to propagating to the point of a pipe break. Therefore, the consequences of an accident are not increased.

(2) The proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

The proposed change does not involve the use or installation of new equipment and the currently installed equipment will not be operated in a new or different manner. No new or different system interactions are created and no new processes are introduced. The proposed changes will not introduce any new failure mechanisms, malfunctions, or accident initiators not already considered in the design and licensing bases. The proposed change does not affect any SSC associated with an accident initiator. Based on this evaluation, the proposed change does not create the possibility of a new or different kind of accident from any accident previously evaluated.

(3) The proposed change does not involve a significant reduction In a margin of safety.

The proposed change does not alter any RCS leakage detection components. The proposed change only clarifies the design and operability requirements for the containment atmosphere gaseous radioactivity monitor and identifies the capabilities of the containment atmosphere gaseous radioactivity monitors at low RCS activity levels. This change is required since the level of radioactivity in the WCGS reactor coolant has become much lower than what was assumed in the USAR and the gaseous channel can no longer promptly detect a small RCS leak under all operating conditions. The proposed amendment continues to require diverse means of leakage detection equipment with capability to promptly detect RCS leakage.

Although not required by TS, additional diverse means of leakage detection capability are available as described in the USAR Section 5.2.5. Early detection of leakage, as the potential indicator of a crack(s) in the RCS pressure boundary, will thus continue to be in place so that such a condition is known and appropriate actions taken well before any such crack would propagate to a more severe condition. Based on this evaluation, the proposed change does not involve a significant reduction in a margin of safety.

Based on the above evaluation, WCNOC concludes that the proposed amendment presents no significant hazards consideration under the standards set forth in 10 CFR 50.92(c).

Attachment I to ET 05-0007 Page 9 of 10 5.2 APPLICABLE REGULATORY REQUIREMENTS/CRITERIA 10 CFR 50, Appendix A, "General Design Criteria for Nuclear Power Plants," Criterion 4, "Environmental and dynamic effects design bases," requires that structures, systems, and components important to safety be designed to accommodate the effects of, and to be compatible with, the environmental conditions associated with the normal operation, maintenance, testing, and postulated accidents, including loss-of-coolant accidents. These structures, systems, and components shall be appropriately protected against dynamic effects, including the effects of missiles, pipe whipping, discharging fluids that may result from equipment failures, and from events and conditions outside the nuclear power unit. However, dynamic effects associated with postulated pipe ruptures in nuclear power units may be excluded from the design basis when analyses reviewed and approved by the Commission demonstrate that the probability of fluid system piping rupture is extremely low under conditions consistent with the design basis for the piping. Criterion 4 is mentioned here for reference only since RCS leak detection instrumentation evaluated in the leak-before-break evaluations are involved.

10 CFR 50, Appendix A, "General Design Criteria for Nuclear-Power Plants," Criterion 30, "Quality of reactor coolant pressure boundary," requires that means be provided for detecting and, to the extent practical, identifying the location of the source of reactor coolant leakage.

The various means for detecting reactor coolant leakage at WCGS were previously discussed in Section 3.0, "Background."

The WCGS design, with certain clarifications and exceptions, conforms to Regulatory Guide 1.45, "Reactor Coolant Pressure Boundary Leakage Detection Systems," dated May 1973.

Regulatory Guide 1.45 describes acceptable methods for implementing the requirement of Criterion 30 (above) with regard to the selection of leakage detection systems for the reactor coolant pressure boundary. The specific attributes of the reactor coolant leakage detection systems are outlined in Regulatory Position 1 through 9 of Regulatory Guide 1.45. WCGS conformance with Regulatory Guide 1.45 is described in Appendix 3A and USAR Table 5.2-6.

NUREG-0800, Standard Review Plan, Draft Section 3.6.3, "Leak-Before-Break Evaluation Procedures," 52 FR 32626-32633, August 28, 1987, provides NRC staff guidance for evaluation of leakage detection systems to support leak-before-break evaluations. Leak detection systems equivalent to those recommended in Regulatory Guide 1.45 are required for piping inside containment. As stated above, the WCGS design, with certain clarifications and exceptions, conforms to Regulatory Guide 1.45. The diverse RCS Leakage Detection Instrumentation continues to satisfy the Regulatory Guide 1.45 criteria.

10 CFR 50.36, 'Technical Specifications," paragraph (c)(2)(ii)(A), specifies that a TS limiting condition for operation of a nuclear reactor must be established for installed instrumentation that is used to detect, and indicate in the control room, a significant abnormal degradation of the reactor coolant pressure boundary. Currently, the instrumentation addressed in TS 3.4.15 satisfies this requirement.

There will be no changes such that compliance with any of the regulatory requirements and guidance documents above would come into question. The evaluations performed by WCNOC confirm that WCGS will continue to comply with all applicable regulatory requirements.

Attachment I to ET 05-0007 Page 10 of 10

6.0 ENVIRONMENTAL CONSIDERATION

WCNOC has determined that the proposed amendment would change requirements with respect to the installation or use of a facility component located within the restricted area, as defined in 10 CFR 20, or would change an inspection or surveillance requirement. However, WCNOC has evaluated the proposed amendment and has determined that the amendment does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amount of effluent that may be released offsite, or (iii) a significant increase in the individual or cumulative occupational radiation exposure. Accordingly, the proposed amendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22 (b), an environmental assessment of the proposed amendment is not required.

7.0 REFERENCES

7.1 NUREG-1061, Volume 3, "Report of the U.S. Nuclear Regulatory Commission Piping Review Committee - Evaluation of Potential for Pipe Breaks," November 1984.

7.2 Regulatory Guide 1.45, "Reactor Coolant Pressure Boundary Leakage Detection Systems," May 1973.

7.3 WCGS Updated Safety Analysis Report, Revision 18.

7.4 WCGS Environmental Report - Operating Licensing Stage (letter KMLNRC-023 dated August 19, 1980).

Attachment II to ET 05-0007 Page 1 of 8 ATTACHMENT 11 MARKUP OF TECHNICAL SPECIFICATION BASES

Attachment 11 to ET 05-0007

• Page 2of8 RCS Leakage Detection Instrumentation B 3.4.15 B 3.4 REACTOR COOLANT SYSTEM (RCS)

B 3.4.15 RCS Leakage Detection Instrumentation BASES BACKGROUND GDC 30 of Appendix A to 10 CFR 50 (Ref. 1) requires means for detecting and, to the extent practical, identifying the location of the source of RCS LEAKAGE. Regulatory Guide 1.45 (Ref. 2) describes acceptable methods for selecting leakage detection systems.

Leakage detection systems must have the capability to detect significant reactor coolant pressure boundary (RCPB) degradation as soon after occurrence as practical to minimize the potential for propagation to a gross failure. Thus, an early indication or warning signal is necessary to permit proper evaluation of all unidentified LEAKAGE.

Industry practice has shown that water flow changes of 0.5 to 1.0 gpm can be readily detected in contained volumes by monitoring changes in water level, in flow rate, or in the operating frequency of a pump (Ref. 2).

The Containment Sump Level and Flow Monitoring System used to collect unidentified LEAKAGE and Containment Cooler Condensate Monitoring System are instrumented to alarm for increases of 0.5 to 1.0 gpm in the normal flow rates. The instrumentation provided is such that over a period of time (1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> or more), the collected flow rate can be determined with an accuracy of better than 1.0 gpm (Ref. 3). This sensitivity is acceptable for detecting increases in unidentified LEAKAGE.

The reactor coolant contains radioactivity that, when released to the containment. can be detected by radiation monitorina instrumentation.

dfor a gw wee ther~er, ui acptedc rrosioV ha /

zbeen famed 1 fissiorfprodyts apgear ffi fuelerementladdi ga co__aminatiofi or cla ding dect Instrument sensitivities of 10 ' gCilcc radioactivity for particulate monitoring and of l O6tCi/cc radioactivity for gaseous monitoring are practical for these leakage detection systems.

Radioactivity detection systems (GT RE-31 or GT RE-32) are included for monitoring both particulate and gaseous activities because of their sensitivities and rapid responses to RCS LEAKAGE.

(1:se~ ~D An increase in humidity of the containment atmosphere would indicate release of water vapor to the containment. Dew point temperature measurements can thus be used to monitor humidity levels of the containment atmosphere as an indicator of potential RCS LEAKAGE. A I OF increase in dew point is well within the sensitivity range of available instruments.

Wolf Creek - Unit 1 B 3.4.1 5-1 Revision 2

05-0007 110 ET a.

Attachment II to ET 05-0007 Page3of8 INSERT A The sensitivity of the containment air particulate monitors for primary coolant leakage detection is dependent on both the primary coolant activity level and the background radiation level in containment which is dependent upon the power level, percent failed fuel, crud bursts, iodine spiking, and natural radioactivity brought in by the containment purge.

Shortly after startup and also during steady state operation with low levels of fuel defects, the level of radioactivity in the reactor coolant is lower than what was assumed in the original design basis calculation. Using a reactor coolant source term based on Cycle 13 data, with no fuel defects, it was determined that the containment air particulate monitors are capable of detecting a one gpm leak in one hour (Ref. 6).

The measurement of containment atmosphere gaseous radioactivity is less sensitive than the measurement of particulate radioactivity for the purpose of detecting RCS leakage. Evaluations have shown that the pre-existing containment radioactive gaseous background levels for which reliable detection is possible is dependent upon the reactor power level, percent failed fuel in the reactor, and air volume exchange brought about by the containment purge system. With primary coolant radionuclide concentrations less than equilibrium levels, such as during startup and operation with no fuel defects, the increase in detector count rate due to leakage will be partially masked by 1) the statistical variation of the minimum detector background count rate, and 2) the Ar-41 activation activity rendering reliable detection of a I gpm leak uncertain.

Operating experience has shown activated Ar-41 gaseous background radiation levels that would partially mask the detection of a I gpm leak from the RCS with low radioactivity concentrations in the reactor coolant. However, the monitor is capable of detecting an RCS-to-containment atmosphere leak if elevated reactor coolant gaseous activity is present.

1 to ET 05-0007 Page 4 of 8 RCS Leakage Detection Instrumentation

, B 3.4.15 BASES APPLICABLE locations are utilized, if needed, to ensure that the transport delay time of SAFETY ANALYSES the leakage from its source to an instrument location yields an acceptable (continued) overall response time.

The safety significance of RCS LEAKAGE varies widely depending on its source, rate, and duration. Therefore, detecting and monitoring RCS LEAKAGE into the containment area is necessary. Quickly separating the identified LEAKAGE from the unidentified LEAKAGE provides quantitative information to the operators, allowing them to take corrective action should a leak occur detrimental to the safety of the unit and the public.

RCS leakage detection instrumentation satisfies Criterion 1 of 10 CFR 50.36(c)(2)(ii).

LCO One method of protecting against large RCS leakage derives from the ability of instruments to rapidly detect extremely small leaks. This LCO requires instruments of diverse monitoring principles to be OPERABLE to provide a high degree of confidence that extremely small leaks are detected in time to allow actions to place the plant in a safe condition, when RCS LEAKAGE indicates possible RCPB degradation.

The LCO is satisfied when monitors of diverse measurement means are available. Thus, the Containment Sump Level and Flow Monitoring System, one containment atmosphere particulate radioactivity monitor and either the Containment Cooler Condensate Flow Monitoring System or one containment atmosphere gaseous radioactivity monitor provide an acceptable minimum.

For containment atmosphere gaseous and particulate radioactivity monitor instrumentation, OPERABILITY involves more than OPERABILITY of the channel electronics. OPERABILITY also requires correct valve lineups, sample pump operation, and, for particulate monitors, sample line insulation and heat tracing, as well as detector OPERABILITY, since these supporting features are necessary for the monitors to rapidly detect RCS LEAKAGE.

APPLICABILITY Because of elevated RCS temperature and pressure in MODES 1, 2, 3, and 4, RCS leakage detection instrumentation is required to be OPERABLE.

In MODE 5 or 6, the temperature is required to be s 200 0F and pressure is maintained low or at atmospheric pressure. Since the temperatures and pressures are far lower than those for MODES 1, 2, 3, and 4, the likelihood of leakage and crack propagation are much smaller. Therefore, the requirements of this LCO are not applicable in MODES 5 and 6.

Wolf Creek - Unit 1 B 3.4.15-3 Revision 9 1to ET 05-0007 Page5of8 INSERT B The measurement of containment atmosphere gaseous radioactivity is less sensitive than the measurement of particulate radioactivity for the purpose of detecting RCS leakage under very low RCS activity conditions. However, it will provide a positive indication of leakage in the event that high levels of reactor coolant gaseous activity exist as a result of fuel cladding defects.

Given the potential limitations of the containment atmosphere gaseous radioactivity monitor at conditions when low radioactivity levels are present in the reactor coolant, OPERABILITY is based on the monitor's ability to meet the required Surveillances and not on its ability to indicate a I gpm RCS boundary leakage in one hour.

Attachment II to ET 05-0007

' Page 6 of 8 RCS Leakage Detection Instrumentation I B 3.4.15 BASES SURVEILLANCE SR 3.4.15.3. SR 3.4.15.4. and SR 3.4.15.5 (continued)

REQUIREMENTS typical refueling cycle and considers channel reliability. Again, operating experience has proven that this Frequency is acceptable REFERENCES 1. 10 CFR 50, Appendix A, Section IV,GDC 30.

2. Regulatory Guide 1.45.

3. USAR, Section 5.2.5.

4. NUREG-609, 'Asymmetric Blowdown Loads on PWR Primary Systems," 1981.

5. Generic Letter 84-04, "Safety Evaluation of Westinghouse Topical Reports Dealing with Elimination of Postulated Pipe Breaks in PWR Primary Main Loops."

qetest(l Wolf Creek - Unit 1 B 3.4.1 5-7 Revision 0

Attachment 11to ET 05-0007 Page 7 of 8 RCS Operational LEAKAGE B 3.4.13 BASES LCO b. Unidentified LEAKAGE (continued)

One gallon per minute (gpm) of unidentified LEAKAGE is allowed )

as a reaso ble minimum detectable amount that the ato, orhaaaiiea urn(Jeydmonitoring equipment C<~ can detect within a reasonable time period. Violation of this LCO could result in continued degradation of the RCPB, if the LEAKAGE

= is from the pressure boundary.

c. Identified LEAKAGE Up to 10 gpm of identified LEAKAGE is considered allowable because LEAKAGE is from known sources that do not interfere with detection of unidentified LEAKAGE and is well within the capability of the RCS Makeup System. Identified LEAKAGE includes LEAKAGE to the containment from specifically known and located sources, but does not include pressure boundary LEAKAGE or controlled reactor coolant pump (RCP) seal leakoff (a normal function not considered LEAKAGE). Violation of this LCO could result in continued degradation of a component or system.

d. Primary to Secondary LEAKAGE through All Steam Generators (SGs)

Total primary to secondary LEAKAGE amounting to I gpm through all SGs produces acceptable offsite doses in the accident analyses involving secondary steam discharge to the atmosphere. Violation of this LCO could exceed the offsite dose limits for these accidents.

Primary to secondary LEAKAGE must be included in the total allowable limit for identified LEAKAGE.

e. Primary to Secondary LEAKAGE through Any One SG The 500 gallons per day limit on one SG is based on the assumption that a single crack leaking this amount would not propagate to a SGTR under the stress conditions of a LOCA or a, main steam line rupture. If leakage is through many cracks, then the cracks are very small, and the above assumption is conservative.

APPLICABILITY In MODES 1, 2, 3, and 4, the potential for RCPB LEAKAGE is greatest when the RCS is pressurized.

Wolf Creek - Unit 1 B 3.4.13-3 Revision 0

Attachment II to ET 05-0007 Page 8 of 8 . RCS Operational LEAKAGE B 3.4.13 BASES SURVEILLANCE SR 3.4.13.1 (continued)

REQUIREMENTS appear as unidentified LEAKAGE and can only be positively identified by inspection. It should be noted that LEAKAGE past seals and gaskets is not pressure boundary LEAKAGE. Unidentified LEAKAGE and identified LEAKAGE are determined by performance of an RCS water inventory balance. Primary to secondary LEAKAGE is also measured by performance of an RCS water inventory balance in conjunction with effluent monitoring within the secondary steam and feedwater systems.

The RCS water inventory balance must be met with the reactor at steady state operating conditions (stable temperature, power level, pressurizer and makeup tank levels, makeup and letdown, and RCP seal injection and return flows). Therefore, a Note is added allowing that this SR is not required to be performed until 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> after establishing steady state operation. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> allowance provides sufficient time to collect and process all necessary data after stable plant conditions are established.

Steady state operation is preferred when performing a proper inventory balance since calculations during non-steady state conditions must account for the changing parameters. For RCS operational LEAKAGE determination by water inventory balance, steady state is defined as stable RCS pressure, temperature, power level, pressurizer and makeup tank levels, makeup and letdown, and RCP seal injection and return flows. An early warning of pressure boundary LEAKAGE or unidentified LEAKAGE the automatic systems that monitor the containment atmosphere radioactivity and the containment sump level. It should be noted that LEAKAGE past seals and gaskets is not pressure boundary LEAKAGE. These leakage detection systems are specified in LCO 3.4.15, "RCS Leakage Detection Instrumentation."

The 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> Frequency is a reasonable interval to trend LEAKAGE and recognizes the importance of early leakage detection in the prevention of accidents. When non-steady state operation precludes surveillance performance, the surveillance should be performed in accordance with the Note, provided greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> have elapsed since the last performance.

SR 3.4.13.2 This SR provides the means necessary to determine SG OPERABILITY in an operational MODE. The requirement to demonstrate SG tube Wolf Creek - Unit 1 B 3.4.13-5 Revision 12

Attachment III to ET 05-0007 Page 1 of 6 ATTACHMENT III MARKUP OF USAR

Attachment III to ET 05-0007 Page2of 6 WOLF CREEK DISCUSSION:

Westinghouse practices achieve the same purpose as Regulatory Guide 1.43 by requiring qualification of any "high heat input" processes, such as the submerged-arc wide-strip welding process and the submerged-arc 6-wire process used on ASME SA-508, Class 2, material, with a performance test as described in Regulatory Position C.2 of the guide. No qualifications are required by the regulatory guide for ASME SA-533 material and equivalent chemistry for forging grade ASME SA-508, Class 3, material.

The fabricator monitors and records the weld parameters to verify agreement with the parameters established by the procedure qualification as stated in Regulatory Position C.3.

Stainless steel weld cladding of low-alloy steel components is not employed on components outside the NSSS.

REGULATORY GUIDE 1.44 REVISION 0 DATED 5/73 Control of the Use of Sensitized Stainless Steel DISCUSSION:

The recommendations of this regulatory guide are met as described in Table 6.1-4.

REGULATORY GUIDE 1.45 REVISION 0 DATED 5/73 Reactor Coolant Pressure Boundary Leakage Detection Systems DISCUSSION:

The recommendations of this regulatory guide are met as described in Table 5.2-REGULATORY GUIDE 1.46 REVISION 0 DATED 5/73 Protection Against Pipe Whip Inside Containment DISCUSSION:

The recommendations of this regulatory guide are met as described in Table 3.6-2 for the balance of plant and Section 3.6.1 for the NSSS.

REGULATORY GUIDE 1.47 REVISION 0 DATED 5/73 Bypassed and Inoperable Status Indication for Nuclear Power Plant Safety Systems DISCUSSION:

The recommendations of this regulatory guide are met as described in Table 7.5-

3. In addition, the bypassed and inoperable indicating system meets Branch Technical Position ICSB 21 titled Guidance for Application of Regulatory Guide 1.47.

3A-18 Rev. 9 l

, Attachment III to ET 05-0007 1 Page 3 of 6 WOLF CREEK tank level that is within the sensitivity range of the level indicators. The charging pump flow would automatically increase to try to maintain pressurizer level. Charging pump discharge flow indication is provided in the control room.

SUMP PUMP OPERATION - Since a leak in the primary system may result in reactor coolant flowing into the containment normal or instrument tunnel sumps, gross leakage can be indicated by an increase in the frequency of operation of the containment normal or the containment instrument tunnel sump pumps. Pump operation can be monitored from the control room.

LIQUID INVENTORY - Larger leaks may also be detected by unscheduled increases in the amount of reactor coolant makeup water which is required to maintain the normal level in the pressurizer. Pressurizer level can be monitored in the control room. Total makeup water flow is also available from the plant.

computer.

5.2.5.2.3 Component Operation CONTAINMENT AIR PARTICULATE MONITOR - Particulate activity is determined from the containment free volume and the coolant fission and corrosion product particulate activity concentrations. Any increase of more than two standard deviations above the count rate for background would indicate a possible leak.

The total particulate activity concentration above background, due to an abnormal leak and natural decay, increases almost linearly with time for the first several hours after the beginning of a leak. As shown in Figure 5.2-2, with 0.1-percent failed fuel, containment background airborne particulate radioactivity equivalent to 10-4 percent/day, and a partition factor equal to 0.01 (NUREG-0017 assumptions), a 1-gpm leak would be detected in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Larger leaks would be detected in proportionately shorter times (exclusive of sample transport time, which remains constant). The detection capabilities and response times are shown on Figure 5.2-2.-

The leakage flow rate can be determined from the count rate when the specific background radioactivity present before the leakage begins is known. The background activity is dependent upon the power level, percent failed fuel, crud bursts, iodine spiking, and natural radioactivity brought in by the containment purge.

CONTAINMENT GASEOUS RADIOACTIVITY MONITOR - Gaseous radioactivity is determined from the containment free volume and the gaseous activity concentration of the reactor coolant. Any increase more than two standard deviations above the count rate for background would indicate a possible leak. The total gaseous activity level above background (after 1 year of normal operation) increases 1 )at bu+/- g; a..josire. ion CC Ike of avg 4Ve,. evtz ikaesra-c1r e-oo 9 ,~bL~ optcic; equips~s a! tau t DF L-~o d dofan 5.2-40 Rev. 10 l

Attachment III to ET 05-0007 Page 4 of 6 WOLF CREEK almost linearly for the first several hours after the beginning of the leak.

As specified in Figure 5.2-2, with 0.1-percent failed fuel, containment background airborne gaseous radioactivity equivalent to 1 percent/day, and a partition factor equal to-l (NUREG-0017 assumptions), a l-gpm leak would be detected within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Larger leaks would be detected in proportionately shorter times (exclusive of the sample transport time which remains constant).

The detection capabilities and response times are shown on Figure 5.2-2.

GiD The leakage flow rate can be determined from the count rate when the specific background radioactivity present before the leakage begins is known. e (bac gro ed astivi~y is iepe Rdeny upgd t9 pow ~rleye, percen faild fue ,nd CONTAINMENT PURGE MONITORS - The containment purge monitors function the same as the containment air particulate and gaseous radioactivity monitors, except that the purge monitors sample from the containment purge exhaust line.

CONTAINMENT COOLER CONDENSATE MONITORING SYSTEM - The condensate flow rate is a function of containment humidity, essential service water temperature leaving the coolers, and containment purge rate. The water vapor dispersed by a 1 gpm leak is much greater than the water vapor brought in with the outside air. Air brought in from the outside is heated to 500 F before it enters the containment.

After the air enters the containment, it is heated to 100-120 0 F so that the relative humidity drops. The water vapor'brought in with the outside air does not build up in the containment since it is continually purged. The most important factor in condensing the water vapor is the temperature of the essential service water which is provided to the containment coolers. This water can vary between 38 - 1000 F on the outlet of the coolers, depending on seasonal conditions.

Level changes of as little 'as 0.25 inches in the cooler condensate standpipes can be detected. Increases in the condensation rates over-normal background are monitored by the BOP computer based upon level checks each minute in order to determine the unidentified leakage. Figure 5.2-2 shows the detection capabilities of the system for various seasonal conditions with no airborne identified leakage. Normal background leakage will increase containment humidity to the point where condensation will more readily occur and, thereby, will improve the detection capabilities of this system.

5.2-41 Rev. 0

Attachment IlIl to ET 05-0007 Page 5 of 6 INSERT C Evaluations have shown that the pre-existing containment radioactive gaseous background levels for which reliable detection is possible is dependent upon the reactor power level, percent failed fuel, and natural radioactivity brought in by the containment purge. With primary coolant concentrations less than equilibrium levels, such as during reactor startup and operation with no fuel defects, the increase in detector count rate due to leakage will be partially masked by 1) the statistical variation of the minimum detector background count rate, and 2) the Ar-41 activation activity rendering reliable detection of a 1 gpm leak uncertain.

Operating experience has shown activated Ar-41 gaseous background radiation levels that would partially mask the detection of a 1 gpm leak. However, the monitor is capable of detecting an RCS to containment atmosphere leak if elevated reactor coolant gaseous activity is present.

INSERT D This method is limited by the fact that large uncertainties are possible when determining the associated leak by calculation. Therefore, in the event of an alarm or increasing trend on these monitors, a water inventory balance is normally performed to determine the equivalent RCS leak rate.

.1

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CD ca)

WOLF CREEK 0) 3 0 (D 0)

TABLE 5.2-6 (Sheet 2) 5.

-I 0

Regulatory Guide 1.45 Position 0

01 (2) airborne particulate radioactivity monitoring. radioactivity monitoring, airborne 0 The third method may be selected from the gaseous radioactivity monitoring, 0 following: containment cooler condensate monitoring, -4 and containment atmosphere humidity

a. monitoring of condensate flow rate monitoring.

from air coolers,

b. monitoring of airborne gaseous radio-activity.

Humidity, temperature, or pressure monitoring:- ~

_ . 1 1 _

of the containment atmosphere should be considered .. _ ..

as alarms or indirect indication of leakage to the containment.

4. Provisions should be made to monitor systems 4. Complies. Refer to Sections connected to the RCPB for signs of intersystem 5.2.5.2.1, 9.3.3, and 11.5.

leakage. Methods should include radioactivity monitoring and indicators to show abnormal water levels or flow in the affected area.

5. The sensitivity and response time of each 5. Complies, as described in Section-leakage detection system in regulatory position 5.2.5.2.3 and as shown on Figure 5.2-2 e

3. above employed for unidentified leakage should be adequate to detect a leakage rate, or its equivalent, of one gpm in less than one hour.

6. The leakage detection systems should be 6. Complies. The airborne particulate capable of performing their functions following radioactivity system is designed to seismic events that do not require plant shutdown. remain functional when subjected to the The airborne particulate radioactivity monitoring SSE. Refer to Sections 11.5.2.3.2.2 and system should remain functional when subjected to 11.5.2.3.2.3. The remaining leakage the SSE. detection systems can reasonably be Rev. 0 K WWSMh4el-e o g esv" WC' FIC

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, T.-3 V-ntaff oFct' d~Ck.t%\J't\

Ve-% coyteebn ofRfuot VVS iitnl4 sInhv he6IL ranr Cocr ae rWeeA ek nVAW-o4 by ofese VsdW iees Ad bR t at twn 6QaN . .1.4.

Attachment IV to ET 05-0007 Page 1 of 1 LIST OF COMMITMENTS The following table identifies those actions-committed to by WCNOC in this document. Any other statements in this submittal are provided for information purposes and are not considered to be commitments. Please direct questions regarding these commitments to Mr. Kevin Moles at (620) 364-4126.

COMMITMENT The proposed changes to the Technical Specification Bases

! Due Date/Event Within 90 days of l

and USAR will be implemented within 90 days of NRC NRC approval .

approval.