TSTF-10-24, Submittal of TSTF-514, Revision 3, Revise BWR Operability Requirements and Actions for RCS Leakage Instrumentation.
| ML103280389 | |
| Person / Time | |
|---|---|
| Site: | Technical Specifications Task Force |
| Issue date: | 11/24/2010 |
| From: | Browning R, Croft W, Raidy T, Schrader K BWR Owners Group, PWR Owners Group, Technical Specifications Task Force |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| TSTF-10-24 | |
| Download: ML103280389 (40) | |
Text
TECHNICAL SPECIFICATIONS TASK FORCE TSTF A JOINT OWNERS GROUP ACTIVITY November 24, 2010 TSTF-10-24 PROJ0753 Attn: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001
SUBJECT:
Submittal of TSTF-514, Revision 3, "Revise BWR Operability Requirements and Actions for RCS Leakage Instrumentation"
Dear Sir or Madam:
Attached for NRC review is Revision 3 of TSTF-514, "Revise BWR Operability Requirements and Actions for RCS Leakage Instrumentation." At the November 4, 2010 TSTF NRC public meeting, the NRC stated that the model application and draft Safety Evaluation for TSTF-514 will require the licensee to specify in the model application and the Bases the administrative means used to monitor Reactor Coolant System (RCS) leakage when the primary containment atmospheric gaseous radiation monitor is the only operable monitor.
Previous revisions of TSTF-514 did not require licensee to specify the administrative means of monitoring RCS leakage. Revision 3 revises the justification and Bases to be consistent with the model application and draft Safety Evaluation.
In a letter from J. E. Dyer (NRC) to TSTF dated March 27, 2009, the review of TSTF-514 has been granted an exemption from review fees.
Should you have any questions, please do not hesitate to contact us.
Kenneth J. Schrader (PWROG/W) Roy A. Browning (BWROG)
Thomas W. Raidy (PWROG/CE) Wendy E. Croft (PWROG/B&W)
Enclosure cc: Robert Elliott, Technical Specifications Branch, NRC Michelle Honcharik, Licensing Processes Branch, NRC 11921 Rockville Pike, Suite 100, Rockville, MD 20852 Phone: 301-984-4400, Fax: 301-984-7600 Administration by EXCEL Services Corporation
BWROG-118, Rev. 0 TSTF-514, Rev. 3 Technical Specification Task Force Improved Standard Technical Specifications Change Traveler Revise BWR Operability Requirements and Actions for RCS Leakage Instrumentation NUREGs Affected: 1430 1431 1432 1433 1434 Classification 1) Technical Change Recommended for CLIIP?: Yes Correction or Improvement: Improvement NRC Fee Status: Exempt Benefit: Avoids Future Amendments See attached.
Revision History OG Revision 0 Revision Status: Closed Revision Proposed by: BWROG Revision
Description:
Original Issue Owners Group Review Information Date Originated by OG: 14-Jan-09 Owners Group Comments (No Comments)
Owners Group Resolution: Approved Date: 18-Feb-09 TSTF Review Information TSTF Received Date: 14-Jan-09 Date Distributed for Review 06-Feb-09 OG Review Completed: BWOG WOG CEOG BWROG TSTF Comments:
(No Comments)
TSTF Resolution: Approved Date: 18-Feb-09 NRC Review Information NRC Received Date: 18-Feb-09 NRC Comments:
Fee exemption granted on 3/30/09.
TSTF Revision 1 Revision Status: Closed Revision Proposed by: NRC 24-Nov-10 Traveler Rev. 3. Copyright(C) 2010, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.
BWROG-118, Rev. 0 TSTF-514, Rev. 3 TSTF Revision 1 Revision Status: Closed Revision
Description:
TSTF-514 is revised to reflect the industry's response to the NRC's 6/11/2009 Request for Additional Information.
Specific changes are:
- 1. The Background section of the Bases is revised to include the optional statement, "[In addition to meeting the OPERABILITY requirements, the monitors are typically set to provide the most sensitive response without causing an excessive number of spurious alarms.]"
- 2. Proposed Required Action F.2 is revised from, "Monitor RCS leakage by administrative means" to "Verify no increase in RCS LEAKAGE over pre-established values."
- 3. The LCO Bases are revised to clarify that the drywell floor drain sump monitoring system is required to quanitify the leakage rate, not leakage.
The justification is revised to reflect these changes.
Owners Group Review Information Date Originated by OG: 14-Aug-09 Owners Group Comments (No Comments)
Owners Group Resolution: Date:
TSTF Review Information TSTF Received Date: 14-Aug-09 Date Distributed for Review 14-Aug-09 OG Review Completed: BWOG WOG CEOG BWROG TSTF Comments:
(No Comments)
TSTF Resolution: Approved Date: 08-Sep-09 NRC Review Information NRC Received Date: 08-Sep-09 NRC Comments:
The NRC requested that the TSTF revise the Traveler to remove the change associated with no operable RCS leakage monitoring instrumentation, as that change was not seen as being directly related to the issue described in Regulatory Issue Summary 2009-02, Rev. 1, "Use of Containment Atmosphere Gaseous Radioactivity Monitors as Reactor Coolant System Leakage Detection Equipment at Nuclear Power Reactors," which was the basis for the TSTF's fee waiver request. In a letter dated June 21, 2010, the TSTF volunteered to pay for the NRC review of the change associated with no Operable RCS leakage monitoring instrumentation. At the July 15, 2010 TSTF/NRC public meeting, the NRC did not accept the TSTF's offer and requested that the TSTF revise the Traveler to remove the changes. The TSTF agreed to revise the Traveler as requested.
Final Resolution: Superceded by Revision 24-Nov-10 Traveler Rev. 3. Copyright(C) 2010, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.
BWROG-118, Rev. 0 TSTF-514, Rev. 3 TSTF Revision 1 Revision Status: Closed TSTF Revision 2 Revision Status: Closed Revision Proposed by: NRC Revision
Description:
The NRC requested that the TSTF revise the Traveler to remove the change associated with no operable RCS leakage monitoring instrumentation, as that change was not seen as being directly related to the issue described in Regulatory Issue Summary 2009-02, Rev. 1, "Use of Containment Atmosphere Gaseous Radioactivity Monitors as Reactor Coolant System Leakage Detection Equipment at Nuclear Power Reactors," which was the basis for the TSTF's fee waiver request. In a letter dated June 21, 2010, the TSTF volunteered to pay for the NRC review of the change associated with no Operable RCS leakage monitoring instrumentation. At the July 15, 2010 TSTF/NRC public meeting, the NRC did not accept the TSTF's offer and requested that the TSTF revise the Traveler to remove the changes. The TSTF agreed to revise the Traveler as requested.
The revision removes the changes to Condition F and the associated change to move Condition E to Condition G. The associated changes to the Bases are removed, as well as the discussion of the removed changes from the justification.
Owners Group Review Information Date Originated by OG: 23-Jul-10 Owners Group Comments (No Comments)
Owners Group Resolution: Approved Date: 04-Aug-10 TSTF Review Information TSTF Received Date: 23-Jul-10 Date Distributed for Review 23-Jul-10 OG Review Completed: BWOG WOG CEOG BWROG TSTF Comments:
(No Comments)
TSTF Resolution: Approved Date: 06-Aug-10 NRC Review Information NRC Received Date: 06-Aug-10 TSTF Revision 3 Revision Status: Active Revision Proposed by: NRC Revision
Description:
The NRC model application and model Safety Evaluation require the licensee to list in the application and the 24-Nov-10 Traveler Rev. 3. Copyright(C) 2010, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.
BWROG-118, Rev. 0 TSTF-514, Rev. 3 TSTF Revision 3 Revision Status: Active Bases the administrative methods that will be used to confirm that RCS leakage is not increasing when the gaseous monitor is the only Operable monitor. The list may be revised after adoption of TSTF-514 under the Technical Specification Bases Control Program.
The justification and the Bases (Condition D, second paragraph) are revised from:
"The administrative methods include, but are not limited to, primary containment and drywell pressure, temperature, and humidity, Component Cooling Water System outlet temperatures and makeup, Reactor Recirculation System pump seal pressure and temperature and motor cooler temperature indications, Drywell cooling fan outlet temperatures, Reactor Building Chiller amperage, Control Rod Drive System flange temperatures, and Safety Relief Valves tailpipe temperature, flow, or pressure."
to "The administrative methods are [primary containment and drywell pressure, temperature, and humidity, Component Cooling Water System outlet temperatures and makeup, Reactor Recirculation System pump seal pressure and temperature and motor cooler temperature indications, Drywell cooling fan outlet temperatures, Reactor Building Chiller amperage, Control Rod Drive System flange temperatures, and Safety Relief Valves tailpipe temperature, flow, or pressure.] "
Owners Group Review Information Date Originated by OG: 08-Nov-10 Owners Group Comments (No Comments)
Owners Group Resolution: Date:
TSTF Review Information TSTF Received Date: 08-Nov-10 Date Distributed for Review 08-Nov-10 OG Review Completed: BWOG WOG CEOG BWROG TSTF Comments:
(No Comments)
TSTF Resolution: Approved Date: 24-Nov-10 NRC Review Information NRC Received Date: 24-Nov-10 Affected Technical Specifications Bkgnd 3.4.6 Bases RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only 24-Nov-10 Traveler Rev. 3. Copyright(C) 2010, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.
BWROG-118, Rev. 0 TSTF-514, Rev. 3 S/A 3.4.6 Bases RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only LCO 3.4.6 Bases RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Ref. 3.4.6 Bases RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Action 3.4.6.C Bases RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Change
Description:
Corrected SR Reference Action 3.4.6.D RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Change
Description:
New Action Action 3.4.6.D RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Change
Description:
Relabeled E Action 3.4.6.D Bases RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Change
Description:
Relabeled E Action 3.4.6.D Bases RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Change
Description:
New Action Action 3.4.6.E RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Change
Description:
Relabeled F Action 3.4.6.E Bases RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Change
Description:
Relabeled F Action 3.4.6.F RCS Leakage Detection Instrumentation NUREG(s)- 1433 Only Change
Description:
Relabeled G Bkgnd 3.4.7 Bases RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Change
Description:
Relabeled G S/A 3.4.7 Bases RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only LCO 3.4.7 Bases RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Ref. 3.4.7 Bases RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Action 3.4.7.D RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Change
Description:
Relabeled E Action 3.4.7.D RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Change
Description:
New Action Action 3.4.7.D Bases RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Change
Description:
Relabeled E Action 3.4.7.D Bases RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Change
Description:
New Action Action 3.4.7.E RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Change
Description:
Relabeled F 24-Nov-10 Traveler Rev. 3. Copyright(C) 2010, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.
BWROG-118, Rev. 0 TSTF-514, Rev. 3 Action 3.4.7.E Bases RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Change
Description:
Relabeled F Action 3.4.7.F RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Change
Description:
Relabeled G Action 3.4.7.F Bases RCS Leakage Detection Instrumentation NUREG(s)- 1434 Only Change
Description:
Relabeled G 24-Nov-10 Traveler Rev. 3. Copyright(C) 2010, EXCEL Services Corporation. Use by EXCEL Services associates, utility clients, and the U.S. Nuclear Regulatory Commission is granted. All other use without written permission is prohibited.
TSTF-514, Rev. 3 1.0 Description NUREG-1433 Specification 3.4.6, "RCS Leakage Detection Instrumentation," and NUREG-1434 Specification 3.4.7 of the same title require instrumentation 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. The Improved Standard Technical Specifications (ISTS) for BWR/4 plants (NUREG-1433) requires one drywell floor drain sump monitoring system, one channel of either primary containment atmospheric particulate or atmospheric gaseous monitoring system, and (optionally) a primary containment air cooler condensate flow rate monitoring system.
The BWR/6 ISTS (NUREG-1434) requires one drywell floor drain sump monitoring system, one channel of either drywell atmospheric particulate or atmospheric gaseous monitoring system, and (optionally) a drywell air cooler condensate flow rate monitoring system.
Questions have been raised regarding the Operability requirements for these instruments.
In particular, improvements in plant fuel integrity have resulted in a reduction of the Reactor Coolant System (RCS) activity. As a result, the atmospheric radioactivity monitors may not be capable of promptly detecting an increase in RCS leakage.
The proposed change revises the Bases to clearly define the RCS leakage detection instrumentation Operability requirements and to modify the Actions to be taken when the atmospheric gaseous radioactivity monitor is the only Operable monitor to require additional, more frequent monitoring of other indications of RCS leakage and to shorten the time allowed to restore another monitor to Operable status.
2.0 Proposed Change The "RCS Leakage Detection Instrumentation," specification (BWR/4 LCO 3.4.6 and BWR/6 LCO 3.4.7) is revised to add a new Condition. New Condition D is applicable when the atmospheric gaseous radioactivity monitor is the only Operable monitor (i.e., all other monitors are inoperable). The Required Actions require analyzing grab samples of the primary containment (BWR/4) or drywell (BWR/6) atmosphere and monitoring RCS leakage using administrative means every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and restoring another monitor to Operable status within 7 days. The subsequent Conditions are renumbered to reflect in addition of the new Condition.
The Bases are revised to clearly define the RCS leakage detection instrumentation Operability requirements in the LCO Bases and to eliminate discussion from the Bases that could be erroneously construed as Operability requirements. The Bases are also revised to reflect the changes to the Technical Specifications and to more accurately reflect the existing Technical Specifications.
Also, the primary containment and drywell air cooler condensate flow rate monitor is plant-specific, and therefore bracketed in the NUREG. The specifications and Bases are revised to consistently bracket references to this monitor.
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TSTF-514, Rev. 3
3.0 Background
General Design Criterion (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 (RG) 1.45, Revision 0, "Reactor Coolant Pressure Boundary Leakage Detection Systems," May 1973, describes acceptable methods for selecting leakage detection systems. Revision 1 of RG 1.45 was issued in May 2008. However, operating nuclear power plants are not committed to Revision 1 of RG 1.45.
NRC Information Notice (IN) 2005-24, "Non-conservatism in Leakage Detection Sensitivity," (ADAMS Accession No. ML051780073) pointed out that the reactor coolant activity assumptions used for designing the containment radiation gaseous radiation monitor may be greater than the RCS radioactivity level present during normal operation. As a result, the containment gas channel may not be able to detect a 1 gpm leak within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> at the current RCS radioactivity level.
RG 1.45, Rev. 0, Regulatory Position C.2 states that "Leakage to the primary reactor containment from unidentified sources should be collected and the flow rate monitored with an accuracy of one gallon per minute (gpm) or better." Regulatory Position C.3 states, "At least three separate detection methods should be employed and two of these methods should be (1) sump level and flow monitoring and (2) airborne particulate radioactivity monitoring. The third method may be selected from the following: a.
monitoring of condensate flow rate from air coolers, b. monitoring of airborne gaseous radioactivity. Humidity, temperature, or pressure monitoring of the containment atmosphere should be considered as alarms or indirect indication of leakage to the containment." Regulatory Position C.5 states, "The sensitivity and response time of each leakage detection system in regulatory position [C.]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." RG 1.45, Rev. 0, states, "In analyzing the sensitivity of leak detection systems using airborne particulate or gaseous radioactivity, a realistic primary coolant radioactivity concentration assumption should be used. The expected values used in the plant environmental report would be acceptable." Many plants pre-date the issuance of RG 1.45 and their plant-specific licensing basis is described in their UFSAR. In either case, the appropriate sensitivity of the atmospheric radiation monitors is dependent on the design assumptions and the plant licensing basis of each licensee.
The ISTS "RCS Leakage Detection Instrumentation" Bases do not clearly define the basis for Operability for the RCS leakage detection instrumentation. Operability requirements should be defined in the LCO section of the Bases. However, the current Bases contain information that could be construed as Operability requirements in the Background, Applicable Safety Analysis, and LCO sections. In addition, the current Bases do not accurately describe the Operability of a detector as being based on the design assumptions and licensing basis for the plant.
Because the atmospheric gaseous radiation monitor cannot always detect an RCS leak at a rate of 1 gpm within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />, some plants have removed the monitor from the Technical Specification list of required monitors. However, experience has shown that the Page 3
TSTF-514, Rev. 3 containment atmosphere gaseous radiation monitor is useful to detect an increase in RCS leak rate and provides a diverse means to confirm an RCS leak exists when other monitors detect an increase in RCS leak rate. Therefore, the preferred solution is to retain the atmospheric gaseous radiation monitor in the LCO list of required equipment, and to revise the Actions to require additional monitoring and to provide less time before a plant shutdown is required when the atmospheric gaseous radiation monitor is the only Operable monitor.
4.0 Technical Analysis This change will reduce the number of unnecessary MODE changes and requests for enforcement discretion by clarifying the Operability requirements for the RCS leakage detection instrumentation and by allowing a limited time to repair one or more of the inoperable monitors. A plant shut down solely as a result of the loss of the preferred TS monitoring capability could be avoided. The use of alternate leakage detection monitoring for a limited time is an appropriate response to this condition.
The proposed Bases changes will clarify the Operability requirements of the RCS leakage detection instrumentation. All references to RG 1.45 are revised to reference Revision 0 of the RG. Information in the Background and Applicable Safety Analysis sections of the Bases that could be construed as Operability requirements is deleted. The LCO section of the Bases is expanded to provide a detailed discussion of the Operability requirements for each of the required instruments. For the atmospheric radioactivity monitors, the Bases clearly relate Operability to the design assumptions and licensing basis for the plant and a reference to the Final Safety Analysis Report description of the design basis of the monitors is included.
As described in 10 CFR 50.36(c)(2)(i), the Limiting Condition for Operation and associated Operability requirements represent the lowest functional capability or performance levels of equipment required for safe operation of the facility. In practice, the leakage monitoring instrumentation is typically set to provide the most sensitive response without distracting the reactor operators with unnecessary alarms.
When the atmospheric gaseous radiation monitor is the only Operable monitor, the current Technical Specifications require grab samples of the primary containment or drywell atmosphere once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and restoration of the inoperable monitors within 30 days. The proposed change requires analyzing grab samples from the primary containment or drywell atmosphere and monitoring RCS leakage by administrative means once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and restoration of at least one additional monitor within 7 days.
Administrative means of monitoring RCS leakage include monitoring and trending parameters that may indicate an increase in RCS leakage. There are diverse alternative mechanisms from which appropriate indicators may be selected based on plant conditions.
It is not necessary to utilize all of these methods, but a method or methods should be selected considering the current plant conditions and historical or expected sources of unidentified leakage. The Bases list the plant-specific administrative methods, such as primary containment and drywell pressure, temperature, and humidity, Component Page 4
TSTF-514, Rev. 3 Cooling Water System outlet temperatures and makeup, Reactor Recirculation System pump seal pressure and temperature and motor cooler temperature indications, Drywell cooling fan outlet temperatures, Reactor Building Chiller amperage, Control Rod Drive System flange temperatures, and Safety Relief Valves tailpipe temperature, flow, or pressure. Licensees may revise these methods using the Technical Specification Bases Control Program. These indications, coupled with the atmospheric grab samples, are sufficient to alert the operating staff to an unexpected increase in unidentified LEAKAGE.
A primary containment or drywell grab sample is comparable to the atmospheric particulate radiation monitor with respect to the ability to detect RCS leakage. Due to the time to take and analyze the grab sample, this is not a continuous monitoring method.
However, the frequent performance of the grab samples ensures there is no significant loss of monitoring capability during the limited time period allowed by the proposed change. The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> (once per shift) performance of primary containment or drywell grab samples and monitoring by administrative means is reasonable given the availability of the atmospheric gaseous radiation monitor. The 7 day Completion Time to restore another monitor to Operable status is reasonable given the diverse methods employed in the Required Actions to detect an RCS leak and the low probability of a large RCS leak during this period.
5.0 Regulatory Analysis 5.1 No Significant Hazards Consideration The Technical Specification Task Force (TSTF) has evaluated whether or not a significant hazards consideration is involved with the proposed generic change by focusing on the three standards set forth in 10 CFR 50.92, "Issuance of amendment," as discussed below:
- 1. Does the proposed change involve a significant increase in the probability or consequences of an accident previously evaluated?
Response: No.
The proposed change clarifies the Operability requirements for the Reactor Coolant System (RCS) leakage detection instrumentation and reduces the time allowed for the plant to operate when the only Operable RCS leakage detection instrumentation monitor is the atmospheric gaseous radiation monitor. The monitoring of RCS leakage is not a precursor to any accident previously evaluated.
The monitoring of RCS leakage is not used to mitigate the consequences of any accident previously evaluated.
Therefore, it is concluded that this change does not involve a significant increase in the probability or consequences of an accident previously evaluated.
- 2. Does the proposed change create the possibility of a new or different kind of accident from any accident previously evaluated?
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TSTF-514, Rev. 3 Response: No.
The proposed change clarifies the Operability requirements for the Reactor Coolant System (RCS) leakage detection instrumentation and reduces the time allowed for the plant to operate when the only Operable RCS leakage detection instrumentation monitor is the atmospheric gaseous radiation monitor. The proposed change does not involve a physical alteration of the plant (no new or different type of equipment will be installed) or a change in the methods governing normal plant operation.
Therefore, it is concluded that this change does not create the possibility of a new or different kind of accident from any accident previously evaluated.
- 3. Does the proposed change involve a significant reduction in a margin of safety?
Response: No.
The proposed change clarifies the Operability requirements for the Reactor Coolant System (RCS) leakage detection instrumentation and reduces the time allowed for the plant to operate when the only Operable RCS leakage detection instrumentation monitor is the atmospheric gaseous radiation monitor. Reducing the amount of time the plant is allowed to operate with only the atmospheric gaseous radiation monitor Operable increases the margin of safety by increasing the likelihood that an increase in RCS leakage will be detected before it potentially results in gross failure.
Therefore, it is concluded that this change does not involve a significant reduction in a margin of safety.
Based on the above, the TSTF concludes that the proposed change presents no significant hazards considerations under the standards set forth in 10 CFR 50.92(c), and, accordingly, a finding of "no significant hazards consideration" is justified.
5.2 Applicable Regulatory Requirements/Criteria 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 specific attributes of the reactor coolant leakage detection systems are outlined in Regulatory Positions 1 through 9 of Regulatory Guide 1.45, Rev. 0.
10 CFR 50.36, "Technical Specifications," paragraph (c)(2)(ii)(A), specifies that a Limiting Condition for Operation 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. This instrumentation is required by the "RCS Leakage Detection Instrumentation" Specification. The modification of the Actions in Page 6
TSTF-514, Rev. 3 the Specification is not in conflict with the 10 CFR 50.36 requirements. The proposed changes do not adversely impact the ability of the Reactor Coolant System leakage detection system to function as designed and do not impact conformance to the applicable GDCs. Therefore, the proposed changes are consistent with all applicable regulatory requirements or criteria.
Based on the considerations discussed above, (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 Commissions regulations, and (3) the approval of the proposed change will not be inimical to the common defense and security or to the health and safety of the public.
6.0 Environmental Consideration A review has determined that the proposed change would change a requirement with respect to 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, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed change.
7.0 References None.
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TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation 3.4.6 3.4 REACTOR COOLANT SYSTEM (RCS) 3.4.6 RCS Leakage Detection Instrumentation LCO 3.4.6 The following RCS leakage detection instrumentation shall be OPERABLE:
- a. Drywell floor drain sump monitoring system, [and]
- b. One channel of either primary containment atmospheric particulate or atmospheric gaseous monitoring system, and
[ c. Primary containment air cooler condensate flow rate monitoring system. ]
APPLICABILITY: MODES 1, 2, and 3.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Drywell floor drain sump A.1 Restore drywell floor drain 30 days monitoring system sump monitoring system to inoperable. OPERABLE status.
B. Required primary B.1 Analyze grab samples of Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> containment primary containment atmospheric monitoring atmosphere.
system inoperable.
AND B.2 [ Restore required primary 30 days ]
containment atmospheric monitoring system to OPERABLE status.
BWR/4 STS 3.4.6-1 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation 3.4.6 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME C. [ Primary containment C.1 --------------NOTE--------------
air cooler condensate Not applicable when flow rate monitoring required primary system inoperable. containment atmospheric monitoring system is inoperable.
Perform SR 3.4.6.1. Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> ]
NOTE -------------- D.1 Analyze grab samples of Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Only applicable when the the primary containment primary containment atmosphere.
atmospheric gaseous radiation monitor is the only AND OPERABLE monitor.
D.2 Monitor RCS LEAKAGE by Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> administrative means.
D. Drywell floor drain sump monitoring system AND inoperable.
D.3.1 Restore drywell floor drain 7 days AND sump monitoring system to OPERABLE status.
[Primary containment air cooler condensate flow OR rate monitoring system inoperable.] [ D.3.2 Restore primary 7 days ]
containment air cooler condensate flow rate monitoring system to OPERABLE status.
ED. [ Required primary ED.1 Restore required primary 30 days containment containment atmospheric atmospheric monitoring monitoring system to system inoperable. OPERABLE status.
AND OR Primary containment air ED.2 Restore primary 30 days ]
cooler condensate flow containment air cooler rate monitoring system condensate flow rate BWR/4 STS 3.4.6-2 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation 3.4.6 inoperable. monitoring system to OPERABLE status.
FE. Required Action and FE.1 Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> associated Completion Time of Condition A, B, AND
[C, D, or ED] not met.
FE.2 Be in MODE 4. 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> GF. All required leakage GF.1 Enter LCO 3.0.3. Immediately detection systems inoperable.
BWR/4 STS 3.4.6-3 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation 3.4.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.6.1 Perform a CHANNEL CHECK of required primary 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> containment atmospheric monitoring system.
SR 3.4.6.2 Perform a CHANNEL FUNCTIONAL TEST of 31 days required leakage detection instrumentation.
SR 3.4.6.3 Perform a CHANNEL CALIBRATION of required [18] months leakage detection instrumentation.
BWR/4 STS 3.4.6-4 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6 B 3.4 REACTOR COOLANT SYSTEM (RCS)
B 3.4.6 RCS Leakage Detection Instrumentation BASES BACKGROUND GDC 30 of 10 CFR 50, Appendix A (Ref. 1), requires means for detecting and, to the extent practical, identifying the location of the source of RCS LEAKAGE. Regulatory Guide 1.45, Revision 0, (Ref. 2) describes acceptable methods for selecting leakage detection systems.
Limits on LEAKAGE from the reactor coolant pressure boundary (RCPB) are required so that appropriate action can be taken before the integrity of the RCPB is impaired (Ref. 2). Leakage detection systems for the RCS are provided to alert the operators when leakage rates above normal background levels are detected and also to supply quantitative measurement of leakage rates. [In addition to meeting the OPERABILITY requirements, the monitors are typically set to provide the most sensitive response without causing an excessive number of spurious alarms.] The Bases for LCO 3.4.4, "RCS Operational LEAKAGE," discuss the limits on RCS LEAKAGE rates.
Systems for separating the LEAKAGE of an identified source from an unidentified source are necessary to provide prompt and quantitative information to the operators to permit them to take immediate corrective action.
LEAKAGE from the RCPB inside the drywell is detected by at least one of two or three independently monitored variables, such as sump level changes and drywell gaseous and particulate radioactivity levels. The primary means of quantifying LEAKAGE in the drywell is the drywell floor drain sump monitoring system.
The drywell floor drain sump monitoring system monitors the LEAKAGE collected in the floor drain sump. This unidentified LEAKAGE consists of LEAKAGE from control rod drives, valve flanges or packings, floor drains, the Closed Cooling Water System, and drywell air cooling unit condensate drains, and any LEAKAGE not collected in the drywell equipment drain sump. The primary containment floor drain sump has transmitters that supply level indications in the main control room.
The floor drain sump level indicators have switches that start and stop the sump pumps when required. A timer starts each time the sump is pumped down to the low level setpoint. If the sump fills to the high level setpoint before the timer ends, an alarm sounds in the control room, indicating a LEAKAGE rate into the sump in excess of a preset limit.
BWR/4 STS B 3.4.6-1 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6 A flow indicator in the discharge line of the drywell floor drain sump pumps provides flow indication in the control room. The pumps can also be started from the control room.
BWR/4 STS B 3.4.6-2 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6 BASES BACKGROUND (continued)
The primary containment air monitoring systems continuously monitor the primary containment atmosphere for airborne particulate and gaseous radioactivity. A sudden increase of radioactivity, which may be attributed to RCPB steam or reactor water LEAKAGE, is annunciated in the control room. The primary containment atmosphere particulate and gaseous radioactivity monitoring systems are not capable of quantifying LEAKAGE rates, but are sensitive enough to indicate increased LEAKAGE rates of 1 gpm within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Larger changes in LEAKAGE rates are detected in proportionally shorter times (Ref. 3).
[ Condensate from four of the six primary containment coolers is routed to the primary containment floor drain sump and is monitored by a flow transmitter that provides indication and alarms in the control room. This primary containment air cooler condensate flow rate monitoring system serves as an added indicator, but not quantifier, of RCS unidentified LEAKAGE. ]
APPLICABLE A threat of significant compromise to the RCPB exists if the barrier SAFETY contains a crack that is large enough to propagate rapidly. LEAKAGE ANALYSES rate limits are set low enough to detect the LEAKAGE emitted from a single crack in the RCPB (Refs. 4 3 and 54). Each of the leakage detection systems inside the drywell is designed with the capability of detecting LEAKAGE less than the established LEAKAGE rate limits and providing appropriate alarm of excess LEAKAGE in the control room.
A control room alarm allows the operators to evaluate the significance of the indicated LEAKAGE and, if necessary, shut down the reactor for further investigation and corrective action. The allowed LEAKAGE rates are well below the rates predicted for critical crack sizes (Ref. 65).
Therefore, these actions provide adequate response before a significant break in the RCPB can occur.
RCS leakage detection instrumentation satisfies Criterion 1 of 10 CFR 50.36(c)(2)(ii).
LCO This LCO requires instruments of diverse monitoring principles to be OPERABLE to provide confidence that small amounts of unidentified LEAKAGE are detected in time to allow actions to place the plant in a safe condition, when RCS LEAKAGE indicates possible RCPB degradation.
The LCO requires [three] instruments to be OPERABLE.
The drywell floor drain sump monitoring system is required to quantify the unidentified LEAKAGE rate from the RCS. Thus, for the system to be considered OPERABLE, either the flow monitoring or the sump level BWR/4 STS B 3.4.6-3 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6 monitoring portion of the system must be OPERABLE and capable of determining the leakage rate. The identification of an increase in unidentified LEAKAGE will be delayed by the time required for the unidentified LEAKAGE to travel to the drywell floor drain sump and it may take longer than one hour to detect a 1 gpm increase in unidentified LEAKAGE, depending on the origin and magnitude of the LEAKAGE.
This sensitivity is acceptable for containment sump monitor OPERABILITY.
The reactor coolant contains radioactivity that, when released to the primary containment, can be detected by the gaseous or particulate primary containment atmospheric radioactivity monitor. Only one of the two detectors is required to be OPERABLE. Radioactivity detection systems are included for monitoring both particulate and gaseous activities because of their sensitivities and rapid responses to RCS LEAKAGE, but have recognized limitations. Reactor coolant radioactivity levels will be low during initial reactor startup and for a few weeks thereafter, until activated corrosion products have been formed and fission products appear from fuel element cladding contamination or cladding defects. If there are few fuel element cladding defects and low levels of activation products, it may not be possible for the gaseous or particulate primary containment atmospheric radioactivity monitors to detect a 1 gpm increase within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> during normal operation. However, the gaseous or particulate containment primary atmospheric radioactivity monitor is OPERABLE when it is capable of detecting a 1 gpm increase in unidentified LEAKAGE within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> given an RCS activity equivalent to that assumed in the design calculations for the monitors (Reference 6).
[An increase in humidity of the containment atmospheric could indicate the release of water vapor to the containment. Primary containment air cooler condensate flow rate is instrumented to detect when there is an increase above the normal value by 1 gpm. The time required to detect a 1 gpm increase above the normal value varies based on environmental and system conditions and may take longer than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. This sensitivity is acceptable for containment air cooler condensate flow rate monitor OPERABILITY.]
The LCO is satisfied when monitors of diverse measurement means are available. Thus, the drywell floor drain sump monitoring system, in combination with a gaseous or particulate primary containment atmospheric radioactivity monitor [and a primary containment air cooler condensate flow rate monitoring system], provides an acceptable minimum.
The drywell floor drain sump monitoring system is required to quantify the unidentified LEAKAGE from the RCS. Thus, for the system to be considered OPERABLE, either the flow monitoring or the sump level monitoring portion of the system must be OPERABLE. The other monitoring systems provide early alarms to the operators so closer examination of other detection systems will be made to determine the extent of any corrective action that may be required. With the leakage BWR/4 STS B 3.4.6-4 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6 detection systems inoperable, monitoring for LEAKAGE in the RCPB is degraded.
BWR/4 STS B 3.4.6-5 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6 BASES APPLICABILITY In MODES 1, 2, and 3, leakage detection systems are required to be OPERABLE to support LCO 3.4.4. This Applicability is consistent with that for LCO 3.4.4.
ACTIONS A.1 With the drywell floor drain sump monitoring system inoperable, no other form of sampling can provide the equivalent information to quantify leakage. However, the primary containment atmospheric activity monitor
[and the primary containment air cooler condensate flow rate monitor] will provide indication of changes in leakage.
With the drywell floor drain sump monitoring system inoperable, but with RCS unidentified and total LEAKAGE being determined every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (SR 3.4.4.1), operation may continue for 30 days. The 30 day Completion Time of Required Action A.1 is acceptable, based on operating experience, considering the multiple forms of leakage detection that are still available.
B.1 and B.2 With both gaseous and particulate primary containment atmospheric monitoring channels inoperable, grab samples of the primary containment atmosphere must be taken and analyzed to provide periodic leakage information. [Provided a sample is obtained and analyzed once every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, the plant may be operated for up to 30 days to allow restoration of at least one of the required monitors.] [Provided a sample is obtained and analyzed every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, the plant may continue operation since at least one other form of drywell leakage detection (i.e., air cooler condensate flow rate monitor) is available.]
The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> interval provides periodic information that is adequate to detect LEAKAGE. The 30 day Completion Time for restoration recognizes that at least one other form of leakage detection is available.
BWR/4 STS B 3.4.6-6 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6 BASES ACTIONS (continued)
[ C.1 With the required primary containment air cooler condensate flow rate monitoring system inoperable, SR 3.4.6.1 must be performed every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to provide periodic information of activity in the primary containment at a more frequent interval than the routine Frequency of SR 3.4.76.1. The 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> interval provides periodic information that is adequate to detect LEAKAGE and recognizes that other forms of leakage detection are available. However, this Required Action is modified by a Note that allows this action to be not applicable if the required primary containment atmospheric monitoring system is inoperable. Consistent with SR 3.0.1, Surveillances are not required to be performed on inoperable equipment. ]
D.1, D.2, D.3.1, and D.3.2 With the drywell floor drain sump monitoring system [and the primary containment air cooler condensate flow rate monitoring system]
inoperable, the only means of detecting LEAKAGE is the primary containment atmospheric gaseous radiation monitor. A Note clarifies this applicability of the Condition. The primary containment atmospheric gaseous radiation monitor typically cannot detect a 1 gpm leak within one hour when RCS activity is low. In addition, this configuration does not provide the required diverse means of leakage detection. Indirect methods of monitoring RCS leakage must be implemented. Grab samples of the primary containment atmosphere must be taken and analyzed and monitoring of RCS leakage by administrative means must be performed every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to provide alternate periodic information.
Administrative means of monitoring RCS leakage include monitoring and trending parameters that may indicate an increase in RCS leakage.
There are diverse alternative mechanisms from which appropriate indicators may be selected based on plant conditions. It is not necessary to utilize all of these methods, but a method or methods should be selected considering the current plant conditions and historical or expected sources of unidentified leakage. The administrative methods are [primary containment and drywell pressure, temperature, and humidity, Component Cooling Water System outlet temperatures and makeup, Reactor Recirculation System pump seal pressure and temperature and motor cooler temperature indications, Drywell cooling fan outlet temperatures, Reactor Building Chiller amperage, Control Rod Drive System flange temperatures, and Safety Relief Valves tailpipe temperature, flow, or pressure.] These indications, coupled with the atmospheric grab samples, are sufficient to alert the operating staff to an unexpected increase in unidentified LEAKAGE.
BWR/4 STS B 3.4.6-7 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6 The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> interval is sufficient to detect increasing RCS leakage. The Required Action provides 7 days to restore another RCS leakage monitor to OPERABLE status to regain the intended leakage detection diversity.
The 7 day Completion Time ensures that the plant will not be operated in a degraded configuration for a lengthy time period.
[ ED.1 and ED.2 With both the primary containment gaseous and particulate atmospheric monitor channels and the primary containment air cooler condensate flow rate monitor inoperable, the only means of detecting LEAKAGE is the drywell floor drain sump monitor. This condition does not provide the required diverse means of leakage detection. The Required Action is to restore either of the inoperable monitors to OPERABLE status within 30 days to regain the intended leakage detection diversity. The 30 day Completion Time ensures that the plant will not be operated in a degraded configuration for a lengthy time period.]
FE.1 and FE.2 If any Required Action of Condition A, B, [C, D or E D] cannot be met within the associated Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and MODE 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to perform the actions in an orderly manner and without challenging plant systems.
GF.1 With all required monitors inoperable, no required automatic means of monitoring LEAKAGE are available, and immediate plant shutdown in accordance with LCO 3.0.3 is required.
BWR/4 STS B 3.4.6-8 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6 BASES SURVEILLANCE SR 3.4.6.1 REQUIREMENTS This SR is for the performance of a CHANNEL CHECK of the required primary containment atmospheric monitoring system. The check gives reasonable confidence that the channel is operating properly. The Frequency of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is based on instrument reliability and is reasonable for detecting off normal conditions.
SR 3.4.6.2 This SR is for the performance of a CHANNEL FUNCTIONAL TEST of the required RCS leakage detection instrumentation. The test ensures that the monitors can perform their function in the desired manner. The test also verifies the alarm setpoint and relative accuracy of the instrument string. A successful test of the required contact(s) of a channel relay may be performed by the verification of the change of state of a single contact of the relay. This clarifies what is an acceptable CHANNEL FUNCTIONAL TEST of a relay. This is acceptable because all of the other required contacts of the relay are verified by other Technical Specifications and non-Technical Specifications tests at least once per refueling interval with applicable extensions. The Frequency of 31 days considers instrument reliability, and operating experience has shown it proper for detecting degradation.
SR 3.4.6.3 This SR is for the performance of a CHANNEL CALIBRATION of required leakage detection instrumentation channels. The calibration verifies the accuracy of the instrument string, including the instruments located inside containment. The Frequency of [18] months is a typical refueling cycle and considers channel reliability. Operating experience has proven this Frequency is acceptable.
REFERENCES 1. 10 CFR 50, Appendix A, GDC 30.
- 2. Regulatory Guide 1.45, Revision 0, "Reactor Coolant Pressure Boundary Leakage Detection Systems," May 1973.
- 3. FSAR, Section [5.2.7.2.1].
- 43. GEAP-5620, April 1968.
5.4 NUREG-75/067, October 1975.
- 65. FSAR, Section [5.2.7.5.2].
BWR/4 STS B 3.4.6-9 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.6
- 6. FSAR, Section [5.2.7.2.1].
BWR/4 STS B 3.4.6-10 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation 3.4.7 3.4 REACTOR COOLANT SYSTEM (RCS) 3.4.7 RCS Leakage Detection Instrumentation LCO 3.4.7 The following RCS leakage detection instrumentation shall be OPERABLE:
- a. Drywell floor drain sump monitoring system, [and]
- b. One channel of either drywell atmospheric particulate or atmospheric gaseous monitoring system, [ and
[c. Drywell air cooler condensate flow rate monitoring system. ]
APPLICABILITY: MODES 1, 2, and 3.
ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. Drywell floor drain sump A.1 Restore drywell floor drain 30 days monitoring system sump monitoring system to inoperable. OPERABLE status.
B. Required drywell B.1 Analyze grab samples of Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> atmospheric monitoring drywell atmosphere.
system inoperable.
AND B.2 [ Restore required drywell 30 days ]
atmospheric monitoring system to OPERABLE status.
BWR/6 STS 3.4.7-1 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation 3.4.7 ACTIONS (continued)
CONDITION REQUIRED ACTION COMPLETION TIME C. [ Drywell air cooler --------------------NOTE-------------------
condensate flow rate Not applicable when the required monitoring system drywell atmospheric monitoring inoperable. system is inoperable.
C.1 Perform SR 3.4.7.1. Once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> ]
NOTE -------------- D.1 Analyze grab samples of Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Only applicable when the the drywell atmosphere.
drywell atmospheric gaseous monitoring system AND is the only OPERABLE monitor. D.2 Monitor RCS LEAKAGE by Once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />
administrative means.
D. Drywell floor drain sump AND monitoring system inoperable. D.3.1 Restore drywell floor drain 7 days sump monitoring system to AND OPERABLE status.
[Drywell air cooler OR condensate flow rate monitoring system [ D.3.2 Restore drywell air cooler 7 days ]
inoperable.] condensate flow rate monitoring system to OPERABLE status.
ED. [ Required drywell ED.1 Restore required drywell 30 days atmospheric monitoring atmospheric monitoring system inoperable. system to OPERABLE status.
AND OR Drywell air cooler condensate flow rate ED.2 Restore drywell air cooler 30 days ]
monitoring system condensate flow rate inoperable. monitoring system to OPERABLE status.
FE. Required Action and FE.1 Be in MODE 3. 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> BWR/6 STS 3.4.7-2 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation 3.4.7 associated Completion Time of Condition A, B, AND
[C, D, or ED] not met.
FE.2 Be in MODE 4. 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> GF. All required leakage GF.1 Enter LCO 3.0.3. Immediately detection systems inoperable.
SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.4.7.1 Perform CHANNEL CHECK of required drywell 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> atmospheric monitoring system.
BWR/6 STS 3.4.7-3 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation 3.4.7 SURVEILLANCE REQUIREMENTS (continued)
SURVEILLANCE FREQUENCY SR 3.4.7.2 Perform CHANNEL FUNCTIONAL TEST of required 31 days leakage detection instrumentation.
SR 3.4.7.3 Perform CHANNEL CALIBRATION of required [18] months leakage detection instrumentation.
BWR/6 STS 3.4.7-4 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.7 B 3.4 REACTOR COOLANT SYSTEM (RCS)
B 3.4.7 RCS Leakage Detection Instrumentation BASES BACKGROUND GDC 30 of 10 CFR 50, Appendix A (Ref. 1), requires means for detecting and, to the extent practical, identifying the location of the source of RCS LEAKAGE. Regulatory Guide 1.45, Revision 0, (Ref. 2) describes acceptable methods for selecting leakage detection systems.
Limits on LEAKAGE from the reactor coolant pressure boundary (RCPB) are required so that appropriate action can be taken before the integrity of the RCPB is impaired (Ref. 2). Leakage detection systems for the RCS are provided to alert the operators when leakage rates above normal background levels are detected and also to supply quantitative measurement of rates. [In addition to meeting the OPERABILITY requirements, the monitors are typically set to provide the most sensitive response without causing an excessive number of spurious alarms.] The Bases for LCO 3.4.5, "RCS Operational LEAKAGE," discuss the limits on RCS LEAKAGE rates.
Systems for separating the LEAKAGE of an identified source from an unidentified source are necessary to provide prompt and quantitative information to the operators to permit them to take immediate corrective action.
LEAKAGE from the RCPB inside the drywell is detected by at least one of two or three independently monitored variables, such as sump level changes and drywell gaseous and particulate radioactivity levels. The primary means of quantifying LEAKAGE in the drywell is the drywell floor drain sump monitoring system.
The drywell floor drain sump monitoring system monitors the LEAKAGE collected in the floor drain sump. This unidentified LEAKAGE consists of LEAKAGE from control rod drives, valve flanges or packings, floor drains, the Closed Cooling Water System, and drywell air cooling unit condensate drains, and any LEAKAGE not collected in the drywell equipment drain sump. The drywell floor drain sump has transmitters that supply level indications in the main control room.
The floor drain sump level indicators have switches that start and stop the sump pumps when required. A timer starts each time the sump is pumped down to the low level setpoint. If the sump fills to the high level setpoint before the timer ends, an alarm sounds in the control room, indicating a LEAKAGE rate into the sump in excess of a preset limit. A second timer starts when the sump pumps start on high level. Should this timer run out before the sump level reaches the low level setpoint, an alarm is sounded in the control room indicating a LEAKAGE rate into the BWR/6 STS B 3.4.7-1 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.7 sump in excess of a preset limit. A flow indicator in the discharge line of the drywell floor drain sump pumps provides flow indication in the control room.
BWR/6 STS B 3.4.7-2 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.7 BASES BACKGROUND (continued)
The drywell air monitoring systems continuously monitor the drywell atmosphere for airborne particulate and gaseous radioactivity. A sudden increase of radioactivity, which may be attributed to RCPB steam or reactor water LEAKAGE, is annunciated in the control room. The drywell atmosphere particulate and gaseous radioactivity monitoring systems are not capable of quantifying leakage rates, but are sensitive enough to indicate increased LEAKAGE rates of 1 gpm within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. Larger changes in LEAKAGE rates are detected in proportionally shorter times (Ref. 3).
[ Condensate from four of the six drywell coolers is routed to the drywell floor drain sump and is monitored by a flow transmitter that provides indication and alarms in the control room. This drywell air cooler condensate flow rate monitoring system serves as an added indicator, but not quantifier, of RCS unidentified LEAKAGE. ]
APPLICABLE A threat of significant compromise to the RCPB exists if the barrier SAFETY contains a crack that is large enough to propagate rapidly. LEAKAGE ANALYSES rate limits are set low enough to detect the LEAKAGE emitted from a single crack in the RCPB (Refs. 34 and 45). Each of the leakage detection systems inside the drywell is designed with the capability of detecting LEAKAGE less than the established LEAKAGE rate limits and providing appropriate alarm of excess LEAKAGE in the control room.
A control room alarm allows the operators to evaluate the significance of the indicated LEAKAGE and, if necessary, shut down the reactor for further investigation and corrective action. The allowed LEAKAGE rates are well below the rates predicted for critical crack sizes (Ref. 56).
Therefore, these actions provide adequate response before a significant break in the RCPB can occur.
RCS leakage detection instrumentation satisfies Criterion 1 of 10 CFR 50.36(c)(2)(ii).
LCO This LCO requires instruments of diverse monitoring principles to be OPERABLE to provide confidence that small amounts of unidentified LEAKAGE are detected in time to allow actions to place the plant in a safe condition, when RCS LEAKAGE indicates possible RCPB degradation.
The LCO requires [three] instruments to be OPERABLE.
The drywell floor drain sump monitoring system is required to quantify the unidentified LEAKAGE rate from the RCS. Thus, for the system to be considered OPERABLE, either the flow monitoring or the sump level monitoring portion of the system must be OPERABLE and capable of BWR/6 STS B 3.4.7-3 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.7 determining the leakage rate. The identification of an increase in unidentified LEAKAGE will be delayed by the time required for the unidentified LEAKAGE to travel to the drywell floor drain sump and it may take longer than one hour to detect a 1 gpm increase in unidentified LEAKAGE, depending on the origin and magnitude of the LEAKAGE.
This sensitivity is acceptable for containment sump monitor OPERABILITY.
The reactor coolant contains radioactivity that, when released to the drywell, can be detected by the gaseous or particulate drywell atmospheric radioactivity monitor. Only one of the two detectors is required to be OPERABLE. Radioactivity detection systems are included for monitoring both particulate and gaseous activities because of their sensitivities and rapid responses to RCS LEAKAGE, but have recognized limitations. Reactor coolant radioactivity levels will be low during initial reactor startup and for a few weeks thereafter, until activated corrosion products have been formed and fission products appear from fuel element cladding contamination or cladding defects. If there are few fuel element cladding defects and low levels of activation products, it may not be possible for the gaseous or particulate drywell atmospheric radioactivity monitors to detect a 1 gpm increase within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> during normal operation. However, the gaseous or particulate drywell atmospheric radioactivity monitor is OPERABLE when it is capable of detecting a 1 gpm increase in unidentified LEAKAGE within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> given an RCS activity equivalent to that assumed in the design calculations for the monitors (Reference 6).
[An increase in humidity of the drywell atmosphere could indicate the release of water vapor to the drywell. Drywell air cooler condensate flow rate is instrumented to detect when there is an increase above the normal value by 1 gpm. The time required to detect a 1 gpm increase above the normal value varies based on environmental and system conditions and may take longer than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />. This sensitivity is acceptable for containment air cooler condensate flow rate monitor OPERABILITY.]
The LCO is satisfied when monitors of diverse measurement means are available. Thus, the drywell floor drain sump monitoring system, in combination with a gaseous or particulate drywell atmospheric radioactivity monitor [and a drywell air cooler condensate flow rate monitoring system], provides an acceptable minimum.
The drywell floor drain sump monitoring system is required to quantify the unidentified LEAKAGE from the RCS. Thus, for the system to be considered OPERABLE, either the flow monitoring or the sump level monitoring portion of the system must be OPERABLE. The other monitoring systems provide early alarms to the operators so closer examination of other detection systems will be made to determine the extent of any corrective action that may be required. With the leakage detection systems inoperable, monitoring for LEAKAGE in the RCPB is degraded.
BWR/6 STS B 3.4.7-4 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.7 BASES APPLICABILITY In MODES 1, 2, and 3, leakage detection systems are required to be OPERABLE to support LCO 3.4.5. This Applicability is consistent with that for LCO 3.4.5.
ACTIONS A.1 With the drywell floor drain sump monitoring system inoperable, no other form of sampling can provide the equivalent information to quantify leakage. However, the drywell atmospheric activity monitor [and the drywell air cooler condensate flow rate monitor] will provide indications of changes in leakage.
With the drywell floor drain sump monitoring system inoperable, but with RCS unidentified and total LEAKAGE being determined every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (SR 3.4.5.1), operation may continue for 30 days. The 30 day Completion Time of Required Action A.1 is acceptable, based on operating experience, considering the multiple forms of leakage detection that are still available.
B.1 and B.2 With both gaseous and particulate drywell atmospheric monitoring channels inoperable, grab samples of the drywell atmosphere shall be taken and analyzed to provide periodic leakage information. [Provided a sample is obtained and analyzed every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, the plant may be operated for up to 30 days to allow restoration of at least one of the required monitors.] [Provided a sample is obtained and analyzed every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, the plant may continue operation since at least one other form of drywell leakage detection (i.e., air cooler condensate flow rate monitor) is available.]
The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> interval provides periodic information that is adequate to detect LEAKAGE. The 30 day Completion Time for restoration recognizes that at least one other form of leakage detection is available.
BWR/6 STS B 3.4.7-5 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.7 BASES ACTIONS (continued)
[ C.1 With the required drywell air cooler condensate flow rate monitoring system inoperable, SR 3.4.7.1 is performed every 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to provide periodic information of activity in the drywell at a more frequent interval than the routine Frequency of SR 3.4.7.1. The 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> interval provides periodic information that is adequate to detect LEAKAGE and recognizes that other forms of leakage detection are available. However, this Required Action is modified by a Note that allows this action to be not applicable if the required drywell atmospheric monitoring system is inoperable. Consistent with SR 3.0.1, Surveillances are not required to be performed on inoperable equipment. ]
D.1, D.2, D.3.1, and D.3.2 With the drywell floor drain sump monitoring system [and the drywell air cooler condensate flow rate monitoring system] inoperable, the only means of detecting LEAKAGE is the drywell atmospheric gaseous radiation monitor. A Note clarifies this applicability of the Condition. The drywell atmospheric gaseous radiation monitor typically cannot detect a 1 gpm leak within one hour when RCS activity is low. In addition, this configuration does not provide the required diverse means of leakage detection. Indirect methods of monitoring RCS leakage must be implemented. Grab samples of the drywell atmosphere must be taken and analyzed and monitoring of RCS leakage by administrative means must be performed every 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to provide alternate periodic information.
Administrative means of monitoring RCS leakage include monitoring and trending parameters that may indicate an increase in RCS leakage.
There are diverse alternative mechanisms from which appropriate indicators may be selected based on plant conditions. It is not necessary to utilize all of these methods, but a method or methods should be selected considering the current plant conditions and historical or expected sources of unidentified leakage. The administrative methods are [primary containment and drywell pressure, temperature, and humidity, Component Cooling Water System outlet temperatures and makeup, Reactor Recirculation System pump seal pressure and temperature and motor cooler temperature indications, Drywell cooling fan outlet temperatures, Reactor Building Chiller amperage, Control Rod Drive System flange temperatures, and Safety Relief Valves tailpipe temperature, flow, or pressure.] These indications, coupled with the atmospheric grab samples, are sufficient to alert the operating staff to an unexpected increase in unidentified LEAKAGE.
BWR/6 STS B 3.4.7-6 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.7 The 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> interval is sufficient to detect increasing RCS leakage. The Required Action provides 7 days to restore another RCS leakage monitor to OPERABLE status to regain the intended leakage detection diversity.
The 7 day Completion Time ensures that the plant will not be operated in a degraded configuration for a lengthy time period.
[ ED.1 and ED.2 With both the gaseous and particulate drywell atmospheric monitor channels and the drywell air cooler condensate flow rate monitor inoperable, the only means of detecting LEAKAGE is the drywell floor drain sump monitor. This Condition does not provide the required diverse means of leakage detection. The Required Action is to restore either of the inoperable monitors to OPERABLE status within 30 days to regain the intended leakage detection diversity. The 30 day Completion Time ensures that the plant will not be operated in a degraded configuration for a lengthy time period.]
FE.1 and FE.2 If any Required Action of Condition A, B, [C, D or D E] cannot be met within the associated Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> and to MODE 4 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br />. The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions in an orderly manner and without challenging plant systems.
GF.1 With all required monitors inoperable, no required automatic means of monitoring LEAKAGE are available, and immediate plant shutdown in accordance with LCO 3.0.3 is required.
BWR/6 STS B 3.4.7-7 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.7 BASES SURVEILLANCE SR 3.4.7.1 REQUIREMENTS This SR requires the performance of a CHANNEL CHECK of the required drywell atmospheric monitoring system. The check gives reasonable confidence that the channel is operating properly. The Frequency of 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> is based on instrument reliability and is reasonable for detecting off normal conditions.
SR 3.4.7.2 This SR requires the performance of a CHANNEL FUNCTIONAL TEST of the required RCS leakage detection instrumentation. The test ensures that the monitors can perform their function in the desired manner. The test also verifies the alarm setpoint and relative accuracy of the instrument string. A successful test of the required contact(s) of a channel relay may be performed by the verification of the change of state of a single contact of the relay. This clarifies what is an acceptable CHANNEL FUNCTIONAL TEST of a relay. This is acceptable because all of the other required contacts of the relay are verified by other Technical Specifications and non-Technical Specifications tests at least once per refueling interval with applicable extensions. The Frequency of 31 days considers instrument reliability, and operating experience has shown it proper for detecting degradation.
SR 3.4.7.3 This SR requires the performance of a CHANNEL CALIBRATION of the required RCS leakage detection instrumentation channels. The calibration verifies the accuracy of the instrument string, including the instruments located inside the drywell. The Frequency of [18] months is a typical refueling cycle and considers channel reliability. Operating experience has proven this Frequency is acceptable.
REFERENCES 1. 10 CFR 50, Appendix A, GDC 30.
- 2. Regulatory Guide 1.45, Revision 0, "Reactor Coolant Pressure Boundary Leakage Detection Systems," May 1973.
- 3. FSAR, Section [5.2.5.2].
- 34. GEAP-5620, April 1968.
- 45. NUREG-75/067, October 1975.
- 56. FSAR, Section [5.2.5.5.3].
BWR/6 STS B 3.4.7-8 Rev. 3.0, 03/31/04
TSTF-514, Rev. 3 RCS Leakage Detection Instrumentation B 3.4.7
- 6. FSAR, Section [5.2.5.2].
BWR/6 STS B 3.4.7-9 Rev. 3.0, 03/31/04