ML16243A515
| ML16243A515 | |
| Person / Time | |
|---|---|
| Site: | Columbia  |
| Issue date: | 08/30/2016 |
| From: | Javorik A L Energy Northwest |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML16245A273 | List: |
| References | |
| GO2-16-112 | |
| Download: ML16243A515 (24) | |
Text
Alex L. Javorik Columbia Generating Station P.O. Box 968, PE04Richland, WA 99352-0968 Ph. 509-377-8555 F. 509-377-4150 aljavorik@energy-northwest.com GO2-16-11210 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk
Washington, DC 20555-0001
Subject:
COLUMBIA GENERATING STATION, DOCKET NO. 50-397LICENSE AMENDMENT REQUEST FOR RECLASSIFYING QUALITY GROUP OF LOW TEMPERATURE PORTIONS OF REACTOR WATER CLEANUP SYSTEM
Dear Sir or Madam:
In accordance with 10 CFR 50.90, Energy Northwest hereby requests an amendment to Facility Operating License Number NPF-21 for Columbia Generating Station (Columbia). This submittal requests approval to revise the Quality Group designation for the piping, valves, pumps and mechanical modules located in low temperature
portions of the reactor water cleanup (RWCU) system located in the radwaste building from Quality Group C to Quality Group D.Approval of the proposed amendment is requested within one year of the date of the submittal. Once approved, the amendment shall be implemented within 120 days. to this letter provides Energy Northwest's evaluation of the change demonstrating that the relevant Nuclear Regulatory Commission (NRC) requirements continue to be met. Attachment 2 provides existing descriptions of the RWCU system in the Final Safety Analysis Report (FSAR) marked up to show the proposed changes.
This letter and attachments contain no regulatory commitments.
In accordance with 10 CFR 50.91, Energy Northwest is notifying the State of Washington of this amendment request by transmitting a copy of this letter and attachments to the designated State Official.
August 30, 2016
Page 1 of 17 Evaluation of Proposed Change 1.
SUMMARY
OF DESCRIPTIONThe proposed change would reclassify reactor water cleanup (RWCU) piping, valves, pumps and mechanical modules located outside of primary and secondary containment
in the radwaste building from Quality Group C to Quality Group D. The proposed reclassification represents a change in the quality classification for the RWCU system design established for Columbia Generating Station (Columbia). Specifically, the RWCU system design is currently based on the use of Quality Group C components
outside of primary containment as specified by position C.2.c of Regulatory Guide 1.26, Revision 3 (Reference 1). 2.DETAILED DESCRIPTION2.1 Proposed Change The radwaste building houses RWCU filter demineralizer subsystem components and a small portion of return line from the RWCU blowdown line to the radwaste system.
RWCU system components in the radwaste building are depicted in Final Safety Analysis Report (FSAR) Figure 5.4-22.3. The proposed change will involve selected components in the radwaste building between where the 4" RWCU piping exits the reactor building (secondary containment)
and re-enters the reactor building by way of the radwaste corridor (see Figure 1 and , Figure 5.4-22.3 markup).The proposed change will establish a transition
from Quality Group C to Quality Group D at the entry and exit points specified above and include all piping, valves and components, with exceptions as noted below. The seismic category of some of the reclassified components in the radwaste building will also be changed as specified in Attachment 2 and summarized as follows: Filter demineralizers (RWCU-DM-1A & RWCU-DM-1B) will remain Quality Group C, Seismic Category II, and Quality Class II. Low pressure portions of the system downstream from the pressure transition valves (such as the precoating units) will remain less than Code Group C. Large bore (greater than 2" diameter) piping between the entry/exit points noted above will be reclassified from Seismic Category II to Seismic Category II+
1;Quality Class (QC) will remain QC II. Small bore (2" or less diameter) piping between the entry/exit points noted above will remain Seismic Category II.
1 Seismic II+ designation indicates that hangars supporting RWCU piping are qualified for Seismic I loading GO2-16-112
Page 2 of 17 The existing 6" RWCU blowdown line running through the radwaste building is classified as quality group D+
2 and is not impacted by this change Seismic classification of RWCU components in the radwaste building corridor is already Seismic Category II+.
The FSAR is the only licensing basis document that requires changing as a result of this reclassification. No technical specifications (TS) changes are required. 2.2 Reason for Request Columbia's RWCU system was originally designed fully compliant with Regulatory Guide 1.26, Revision 3 guidance as noted in NUREG-0892 (Reference 2). A design
change was completed in 1995 to replace problematic valves in the low temperature
portion of the system with more reliable Quality Group D alternatives. In 2013, the NRC
revisited the reclassification effort and concluded that prior NRC approval should have been obtained before installing Quality Group D components. A severity level IV
violation was issued in 2013 for this issue (Reference 3). Since the violation, Energy Northwest has restored certain components of the system to Quality Group C and is
actively managing all remaining non-conforming components under Columbia's corrective action program.The proposed changes will allow for the portions of the system located in the radwaste building, which were reclassified in 1995, to remain as Quality Group D, thus allowing for currently installed non-conforming components in Columbia's RWCU system to be
accepted as is. This license amendment request establishes a basis for concluding that
an acceptable level of quality and safety will be provided by Quality Group D components in the reclassified portions of the RWCU system. This classification change does not affect the safety related portions of the system. The specified safety function of the RWCU system is to automatically isolate from the reactor coolant pressure boundary (RCPB) and to isolate primary containment. This isolation is accomplished by inboard and outboard containment isolation valves on the suction and return lines to the reactor pressure vessel.The RWCU isolation instrumentation performs the safety related function to automatically isolate the RWCU system upon sensing parameters indicative of a leak in the RWCU piping (RWCU high
delta flow or high blowdown flow). The classification change also does not affect the non-safety related portions of the system located in the reactor building.These portions of the RWCU system pump the reactor water through the regenerative heat exchangers and non-regenerative heat 2 D+ categorization is applied to Radioactive Waste Management structures, systems and components designed in accordance with Regulatory Guide 1.143, Revision 1, October 1979 which may contain ASME N-stamped components (exceeding design requirements) due to implementation of the regulatory guide after component fabrication had commenced GO2-16-112
Page 3 of 17 exchangers in order to cool the fluid so it can be processed through the filter demineralizers without damaging the resins. These portions of the RWCU system also reheat the purified fluid to normal reactor operating temperatures via the regenerative heat exchanger prior to injection into the reactor pressure vessel (RPV).3.TECHNICAL EVALUATION3.1 System Description The RWCU system is an auxiliary system, which continuously purifies reactor water during all modes of reactor operation. The majority of the RWCU system equipment is
located in the reactor building and includes the two main RWCU pumps as well as three regenerative and two non-regenerative heat exchangers. The two filter-demineralizers and supporting equipment are located in the radwaste building. The temperature of the reactor coolant water processed through the filter-demineralizers is limited by resin operating temperature and the piping design limits. Therefore, the reactor coolant must
be cooled from a normal reactor recirculating (RRC) loop operating temperature of
approximately 534°F to approximately 120°F before it enters the filter demineralizers.
This is accomplished by cooling the water in regenerative and non-regenerative heat exchangers. Non-regenerative heat exchangers reject heat to the Reactor Closed
Cooling (RCC) system.Upon exiting the filter demineralizers, the reactor coolant water passes through the regenerative heat exchangers and returns to the reactor via the reactor feedwater (RFW) system. Additional normally closed, effluent flow paths are available including blowdown to the main condenser or the radwaste system. Valves supporting the various effluent paths are all located in the reactor building as depicted in Figure 1. The portion of the RWCU system in the radwaste building processes the low temperature fluid through the filter demineralizers. This portion of the system is classified as non-safety related and is not relied upon to remain functional during and
following a design basis event. The radwaste portion of RWCU system does not
perform any of the functions associated with safety related SSCs as defined in 10 CFR
50.2. Namely it does not assure: the integrity of the RCPB, capability to achieve and maintain safe shutdown, or prevention or mitigation of offsite exposure due to accidents. The non-safety related classification for this portion of the system is also consistent with considerations presented by the NRC in Generic Letter 84-01 (Reference 4) in that the portion of the RWCU system to be reclassified is in the broader important to safety category of equipment subject to General Design Criteria (GDC) 1 requirements.
Page 4 of 17 The extent of safety related equipment within the greater RWCU system is limited to the containment isolation valves and instrumentation supporting the isolation function contained in the TS. Although not safety related, this system is considered important to safety since it is connected to the reactor coolant system and also contains radioactive demineralizer resins. Failure of the system could result in a loss of coolant accident, release of reactor coolant outside containment or release of demineralizer resins. As
such, the system design is in accordance with General Design Criteria 1 in that its
design and quality is established and maintained at a level commensurate with the
importance of the safety functions it performs.The portion of the system located within the primary containment and the small portion located outside of containment up to and including the outboard containment isolation valve are considered part of the RCPB. The other portions of the system are not part of
the RCPB and, in the event of detected reactor coolant leakage, are automatically
isolated by closure of motor-operated containment isolation valves. The TS credited primary containment isolation instrumentation for the RWCU system provides for system isolation using safety related components not affected by this request under the following conditions: differential flow greater than or equal to 67.4 gpm, blowdown flow greater than or equal to 271.7 gpm, temperature in the heat exchanger room greater than or equal to 160 degrees Fahrenheit, heat exchanger room area ventilation differential temperature greater than or equal to 70 degrees Fahrenheit pump room area temperature greater than or equal to 180 degrees Fahrenheit pump room area ventilation differential temperature greater than or equal to 100 degrees Fahrenheit area temperature in the RWCU/reactor core isolation cooling line routing area greater than or equal to 180 degrees Fahrenheit area temperature in the RWCU line routing area greater than or equal to 175 degrees Fahrenheit (Rooms 409 & 509) or 180 degrees Fahrenheit (Rooms 408
& 511) reactor vessel low, low water level (less than or equal to negative 58 inches) standby liquid control system initiation All sensors driving system isolation are located in the reactor building. While area temperature monitoring based isolations would not occur due to a system breach in the radwaste building, the two flow based isolation signals are still available to provide
isolation for leaks in the reclassified portion of the system. 3.2 Current Licensing Basis The system is designed in accordance with Regulatory Guide 1.26. Portions of the RWCU which constitute the RCPB are designed to Quality Group A, while the remaining GO2-16-112
Page 5 of 17 portions (excluding the precoating unit) are designed to Quality Group C , D or D+.System seismic design is in accordance with Regulatory Guide 1.29, Revision 3 (Reference 5). The system is operated to purify reactor water in all modes, maintaining reactor coolant system (RCS) chemistry within limits established in the Licensee
Controlled Specifications to minimize the probability of failure of the reactor coolant pressure boundary as a result of general corrosion or intergranular stress corrosion
cracking (IGSCC).The operating pressure of the main RWCU system process lines outside of containment is above the threshold for consideration as a high energy system in accordance with Branch Technical Position 3-3 (Reference 6) (formerly BTP ASB 3-1). However, the current licensing basis for the system limits the high energy portions of the system to supply and return piping between the RPV and radwaste building as presented in FSAR Table 3.6-1 during original plant licensing. NRC acceptance is documented in section 3.6.1 of NUREG-0892. Although not included as part of this license amendment request, the high-pressure portions of the RWCU system in the radwaste building are being added to the current licensing basis as high energy lines as part of a design
reconstitution effort. The effort will be completed prior to or in conjunction with implementation of the system reclassification. Additional details are presented below. 4.Safety Analysis of Proposed Changes4.1 System Design Attributes - Not Impacted
Section 4.1 of this LAR describes design attributes of the RWCU system that are not being significantly changed. The discussions in this section are presented in topical
areas aligned with Standard Review Plan (SRP) acceptance criteria and system
considerations presented in the standard review plan (References 7 and 8). Since these aspects of the system are not being significantly changed, it is concluded that the system continues to meet applicable regulatory requirements in these areas. 4.1.1 Interconnections with primary coolant and radwaste systems There are no changes to the interconnections with the primary coolant and radwaste systems, or the isolation of the system on low low reactor water level. Additionally, the isolation logic following injection of the standby liquid control system is not impacted by the proposed change. 4.1.2 Resin management and component venting There are no changes to the existing system design or operation related to the control of ion exchange resins used in the filter demineralizers. Resins are prevented from
entering the reactor recirculation system by strainers on each filter demineralizer. Filter demineralizers are isolated when differential pressure between strainer and the filter demineralizer vessel exceeds preset thresholds. Transfer of spent resin to the solid GO2-16-112
Page 6 of 17 waste management system as described in FSAR Section 11.4.2.2 will be maintained.Venting from RWCU components in the radwaste building is processed and monitored by the radwaste building Heating, Ventilation and Air Conditioning (HVAC) system. 4.1.3 Reactor coolant pressure boundary considerations Sections 5.2.3 and 5.2.4 of the FSAR consider the following aspects for those portions of the RWCU system which constitute part of the RCPB: Material properties and compatibility In-service inspection requirements System operation to maintain reactor coolant water chemistry and levels of impurities in a manner which avoids deterioration of the reactor coolant pressure boundary by general corrosion or by intergranular stress corrosion
crackingThe proposed changes are for low temperature portions of the RWCU system located in the radwaste building which are not part of the RCPB. The operation of the system remains unchanged and capabilities and performance are not impacted by the
reclassification. Therefore, the basis under which the current system was found to be
acceptable with regard to RCPB considerations remains unchanged.4.1.4 Internal missile survivability for safety related systems As documented in section 3.5 of the FSAR, safety related systems inside and outside of primary containment are designed to withstand the effects of internally generated missiles. The safety related portions of the RWCU system consist of the piping and
valves from the RPV out to the outermost containment isolation valves and RWCU
system isolation instrumentation included in the technical specifications. All of the safety related portions of RWCU are located in the reactor building (external to the
radwaste building). Evaluation of the potential failure of high energy RWCU piping in
the radwaste building has concluded that there are no credible missiles originating from the RWCU system in the radwaste building. That is, all safety related equipment in the radwaste building is physically separated (by existing walls/ceilings/floors) from any missile source originating from the reclassified portion of the RWCU system; therefore, safe shutdown of the plant is not impacted by the proposed reclassification.4.1.5 Internal flooding protection Section 3.4 of the FSAR describes flood protection for safety related structures, systems and components (SSCs). The RWCU system is considered a potential source of flooding that could impact SSCs essential for safe shutdown or that could result in significant radiological releases. Analysis of potential flooding originating from a high energy line break (HELB) of the reclassified portion of the RWCU system was GO2-16-112
Page 7 of 17 performed and concluded that no safety related systems are impacted and similarly, no postulated flooding effects would result in release of significant radioactivity. Flooding
due to leakage from the reclassified portion of the RWCU system would be precluded from entering the vital island or impacting other safety related SSCs. The internal flooding protection design is adequate for the proposed system reclassification.4.1.6 Environmental qualification Section 3.11 of the FSAR, discusses qualification of important to safety SSCs for all environmental service conditions resulting from normal operations through accidents.
The portions of the RWCU system which are being reclassified do not qualify as
important to safety equipment within the scope of SRP 3.11 consideration. The safety
functions performed by portions of RWCU which are subject to section 3.11 are not impacted by this change. A rupture of the reclassified portion of the RWCU system
could produce harsh environmental conditions in portions of the radwaste building.
Safety related SSCs exposed to the harsh environment are either qualified for the
environment produced (and have been added to the existing environmental qualification program) or are considered "justified mild". Consideration as "justified mild" indicates
that impacted SSCs have no required safety function while exposed to the harsh environment and also will not fail in a way that is detrimental to plant safety.4.1.7 Performance of safety related function There are no changes to the safety related portions of the RWCU system. The primary active safety functions are to isolate the system as needed in response to breaks in the RWCU system or in other systems and to isolate the RWCU system following standby
liquid control (boron) injection. The logic and components supporting these active safety functions are governed by existing technical specification limiting condition for
operation (LCO) 3.3.6.1 - Primary Containment Isolation Instrumentation Function 4-RWCU System Isolation and are not impacted by the proposed change. The reactor building wall structure is sufficient to prevent postulated breaks of the reclassified
portion of the system from impacting the RWCU safety related components in the
reactor building.4.1.8 Control the release of radioactive materials The RWCU system purifies reactor coolant and thus accumulates radioactive materials in gaseous, liquid and solid form. The RWCU system appropriately collects radioactive materials and routes them to the radwaste system. Additionally, administrative controls ensure that the operational limits for filter demineralizer resins are adhered to. Spent resin transfer methods are appropriate to ensure probability of release of radioactive
materials is minimized. The probability that 10 CFR 50 onsite dose limits or 10 CFR 20 offsite dose limits are exceeded due to system operation is thus minimized. See additional discussion under GDC 60 & 61 in section 5.1.1 below.
Page 8 of 17 4.1.9 Radioactivity control The reclassified portions of the RWCU system are designed to minimize the probability that reactor water would be released in quantities that would result in offsite doses exceeding 10 CFR 20 limits.Available leak detection instrumentation capable of terminating releases from a break in the reclassified portion of the system includes safety related differential flow and blowdown flow. The proposed changes do not affect
the physical system interfaces or operational considerations and thus control of radioactivity associated with the system remains adequate. See additional discussion under GDC 60 & 61 in section 5.1.1 below. 4.1.10 Availability, capability and reliability System availability, capability and reliability are not impacted by the reclassification.The reclassified system components have a long operating history in plant with no substantial problems. ANSI B31.1 is a standard used in other mixed safety systems within the plant such as the non-safety related portions of the control rod drive system.
Components required for isolation of the RWCU system are maintained to a quality group consistent with Regulatory Guide 1.26 guidance.
Following the original reclassification in the mid 1990s, a total of 31 Quality Group D valves were installed to replace Quality Group C valves in the filter demineralizer portion of RWCU. Additionally, the internals of 8 Quality Group C valves were replaced with Quality Group D components. The Quality Group D components have performed well in their application. Twenty-nine of the originally replaced valves remain Quality Group D, with the remaining two having been recently restored to Quality Group C in response to
the 2013 violation. The reclassified valves have required nominal maintenance to maintain system performance standards typical of that to be expected for their operating
conditions. There have been no gross failures of any Quality Group D components. As
a whole, the Quality Group D valves have served well and eliminated many of the issues which were present with the problematic Quality Group C valves they replaced.
Based on the long history of acceptable and reliable performance, the use of Quality Group D components in the filter demineralizer portion of RWCU does not conflict with the acceptance criteria in SRP 5.4.8 4.2 Changes to System Design Attributes to Establish Current Safety Basis The following sections describe aspects of the RWCU system which will result in changes to the current licensing basis for the system. Detailed evaluation is provided for each specific concern. This information represents the basis on which Energy
Northwest is requesting the acceptance of the reclassified portion of the RWCU system
in the radwaste building.
Page 9 of 17 4.2.1SRP 5.4.8 (applicability of GDC 1 & 2 ) failures leading to LOCA, release of coolant outside containment or release of demineralizer resins, release of reactor water and radioactive materials outside of containment The system pressures associated with the RWCU system in the radwaste building result in system classification as a high energy system per FSAR Section 3.6.2.1. Failure of
RWCU components in the reclassified portion of the system could result in release of reactor coolant outside of primary containment. However, breaks in the reclassified section would not be considered a LOCA since the portion of the system proposed for reclassification is not part of the reactor coolant pressure boundary. Any breaks in the system are ultimately terminated by closure of the RWCU primary containment isolation
valves in response to detection of the break by primary containment isolation instrumentation installed on the RWCU system. Energy Northwest performed a dose consequence analysis for an RWCU line break in the radwaste building. This analysis utilized the same methods as those for the instrument line break in FSAR 15.6.2. The mass release is calculated using a GOTHIC model of the system which computes the integrated mass release from a double-ended guillotine break of a 4 inch RWCU line given a bounding system isolation time of 70 seconds. The mass release consists of 10,774 lbm liquid and 29,130 lbm vapor. It is conservatively assumed that 10% of the total liquid release will flash to vapor/steam for a total release of 3.02E4 lbm that will
transport dose. The dose consequence analysis was determined using the Columbia design basis site radiological computer code STARDOSE.The model is a simple release to the radwaste building. No hold up is assumed to occur in the building. All activity released from the core is released to the environment. A conservative ventilation exhaust flow rate from the radwaste building is assumed. No
filtration is assumed for either the radwaste building or control room.The source term assumes a spike of 20 times the normal coolant activity, similar to the instrument line break. The isotope selection is all of the noble gases and halogen
isotopes and was taken from the alternative source term (AST) analysis of an
instrument line break. Results of the RWCU HELB analysis are bounded by the existing instrument line break analysis results. 4.2.2 SRP 3.2.2 establishment of acceptable basis for proposed quality group classificationSection 3.2.2 of the Standard Review Plan, states that exceptions to Regulatory Guide 1.26 classifications should be supported with adequate justification for the proposed quality group classification. Regulatory Guide 1.26 establishes that portion of RWCU
beyond the outermost containment isolation valve as quality group C, due to the fact
that it is connected to the reactor coolant pressure boundary. Conformance to this GO2-16-112
Page 10 of 17 classification system is an NRC accepted method of meeting GDC 1 requirements. As noted in Generic Letter 84-01 however, GDC 1 mandates the application of quality
standards and programs commensurate with the importance of the safety function to be
performed. Furthermore, the use of generally recognized codes and standards is explicitly allowed per GDC 1. This LAR establishes a basis for employing the graded
approach (in recognition of importance of the safety function to be performed) allowed
by GDC 1 to reclassify the low temperature portions of the RWCU system in the
radwaste building.SRP 3.2.2 states that changes in classification are normally acceptable only at valve locations. If a classification change does not occur at a valve location (as is proposed in this LAR), then the design must be such that the safety function of the system is not impaired by failure on the lower classification side of the boundary. The most impacting failure in the lower classification portion of the system is postulated as a double ended guillotine break of the 4" RWCU supply or return line.To maintain consistency with existing pipe break analyses, Columbia is extending the existing scope of high energy classification on the RWCU system to include those
portions of the system in the radwaste building that meet the temperature and/or pressure thresholds for high energy classification as specified in BTP 3-3. The activities supporting this design reconstitution of adding the RWCU system in the radwaste building to the list of high energy systems at the plant is being performed as a corrective action. The changes required for the design reconstitution as well as the upgrade of seismic category for RWCU piping in radwaste greater than 2 inches in diameter were
reviewed under 10 CFR 50.59 and determined to not require prior NRC approval. All analyses of postulated breaks of the lower classification portion of the RWCU system
are performed in the same manner as other high energy line break analyses in the
FSAR and include consideration of jet impingement, pipe whip, missile, and flooding
impacts as well as subcompartment pressurization.There is no specific safety function for the portions of the RWCU system proposed for reclassification and the consequences of a break in the system do not preclude safety related components from performing their safety functions. A classification of Quality Group D, as defined in Regulatory Guide 1.26 is appropriate for water containing components that are not part of the reactor coolant pressure boundary but may contain radioactive material such as the radwaste system. The separation provided by the containment isolation valves establishes a functional break in the RWCU system
between the portions with a safety function and the portion without a safety function.
Thus, the portions of the system in the radwaste building are consistent with the guidance for Quality Group D systems when considered independent of the other
portions of the system.In many cases, the materials, design, and fabrication of ASME Section III, Class 3 (Quality Group C) and ANSI B31.1 (Quality Group D) components are equivalent, with the quality requirements being the only appreciable difference. The application of ANSI GO2-16-112
Page 11 of 17 B31.1 requirements to the portions of RWCU located in the radwaste building provides an adequate level of quality and ensures that the facility can be operated without undue risk to the health and safety of the public. 5.REGULATORY EVALUATION5.1 Applicable Regulatory Requirements/Criteria 5.1.1 10 CFR 50 Appendix A General Design Criteria The GDCs directly relevant (per SRP 5.4.8) to the proposed changes to the RWCU system are discussed below. Note that GDC 14 - reactor coolant pressure boundary is part of the overall acceptance criteria for the RWCU system but the proposed changes
do not impact those portions of RWCU which constitute RCPB or are associated with
RCPB isolation. As such, no further discussion of GDC 14 is included. Criterion 1 - Quality Standards and Records.
Structures, systems, and components important to safety shall be designed, fabricated, erected, and tested to quality standards commensurate with the importance of the safety functions to be performed.
Where generally recognized codes and standards are used, they shall be identified and
evaluated to determine their applicability, adequacy, and sufficiency and shall be supplemented or modified as necessary to assure a quality product in keeping with the required safety function. A quality assurance program shall be established and implemented in order to provide adequate assurance that these structures, systems, and components will satisfactorily perform their safety functions. Appropriate records of the design, fabrication, erection, and testing of structures, systems, and components important to safety shall be maintained by or under the control of the nuclear power unit licensee throughout the life of the unit.
The safety related portions of RWCU currently are and will remain designed to applicable standards established by Regulatory Guide 1.26, thus ensuring GDC 1 compliance. The portion of the RWCU system proposed to be reclassified as Quality
Group D is non-safety related. This safety classification was established during initial plant licensing and has not been changed. Energy Northwest maintains a quality assurance program and record management program which meet the requirements of
GDC 1, neither of which is impacted by the proposed changes.
Criterion 2 - Design bases for protection against natural phenomena.
Structures, systems, and components important to safety shall be designed to withstand the effects of natural phenomena such as earthquakes, tornadoes, hurricanes, floods, tsunami, and seiches without loss of capability to perform their safety functions. The design bases for
these structures, systems, and components shall reflect: (1) Appropriate consideration of the most severe of the natural phenomena that have been historically reported for the site and surrounding area, with sufficient margin for the limited accuracy, quantity, and period of time in which the historical data have been accumulated, (2) appropriate GO2-16-112
Page 12 of 17 combinations of the effects of normal and accident conditions with the effects of the natural phenomena and (3) the importance of the safety functions to be performed. As noted above, portions of RWCU in the reactor building (including all safety related portions) are not impacted by the proposed changes. Specific natural phenomena at Columbia which the RWCU system is designed to withstand are limited to earthquakes, tornados and flooding. A summary of the existing GDC 2 compliant design for important
to safety portions of RWCU is provided in the following paragraphs. The proposed reclassification does not impact the existing GDC 2 compliance of the overall RWCU
system.Reclassified portions of the RWCU system are contained within the Seismic Category II portions of the radwaste building. Section 5.4.8 of the SRP allows for non-seismic I design of the system beyond the outermost containment isolation valve. Specifically, Energy Northwest employs a mixed seismic classification design in the radwaste
building which uses Seismic Category I design for those SSCs in the radwaste building which ensure: the integrity of the RCPB, the capability to shut down the reactor and maintain it in a safe shutdown condition, or the capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposure comparable to the exposure limits of 10 CFR
Part 50.67.
The existing design is consistent with SRP 5.4.8 review criteria.
Tornado missile protection in the radwaste building is provided for safety related systems by enclosure in reinforced concrete. Additional radwaste building structure, associated with non-safety related portions, consists of structural steel-framed
construction. The steel framed portions are designed to the Uniform Building Code and
provide tornado missile shielding to portions of the concrete walls and roofs in the radwaste building. Additional shielding from tornado missiles is provided by the neighboring diesel generator and reactor buildings. Exposed radwaste concrete walls and roofs are designed to withstand design basis tornado missiles. The design basis external flood for Columbia is associated with a probable maximum precipitation (PMP) event. This PMP event results in a flood elevation of 433.3 ft mean
sea level (msl) which also accounts for credible wind wave action. The top of the
radwaste building foundation mat is at 437 ft msl and thus no RWCU components are
susceptible to external flooding.
Internal flooding protection compliant with GDC 2 is currently provided for safety related components of the RWCU system and is not impacted by the proposed change.Flooding originating from a worst case break from the RWCU components within the GO2-16-112
Page 13 of 17 scope of reclassification would be isolated by existing safety related leak detection instrumentation prior to creating a substantial flooding concern in the radwaste building.
Therefore, GDC 2 requirements related to flooding are adequately met for the proposed
change.Criterion 60 - Control of releases of radioactive materials to the environment. The nuclear power unit design shall include means to control suitably the release of radioactive materials in gaseous and liquid effluents and to handle radioactive solid wastes produced during normal reactor operation, including anticipated operational
occurrences. Sufficient holdup capacity shall be provided for retention of gaseous and liquid effluents containing radioactive materials, particularly where unfavorable site
environmental conditions can be expected to impose unusual operational limitations
upon the release of such effluents to the environment Gaseous effluents, spent demineralizer resins, and liquid effluents originating from the reclassified portions of the RWCU system from normal and abnormal operating occurrences (AOOs) are collected in closed systems and discharged to the radwaste system for processing and disposal. No changes are being made to the physical system interfaces or system operation and thus appropriate control has been
established over the release of radiological materials originating from the RWCU
system.Criterion 61 - Fuel storage and handling and radioactivity control. The fuel storage and handling, radioactive waste, and other systems which may contain radioactivity shall be designed to assure adequate safety under normal and postulated accident conditions. These systems shall be designed (1) with a capability to permit
appropriate periodic inspection and testing of components important to safety, (2) with
suitable shielding for radiation protection, (3) with appropriate containment, confinement, and filtering systems, (4) with a residual heat removal capability having reliability and testability that reflects the importance to safety of decay heat and other residual heat removal, and (5) to prevent significant reduction in fuel storage coolant
inventory under accident conditions.
General Design Criteria 61 establishes that systems containing radioactivity be designed to assure adequate safety under normal and postulated accident conditions.
GDC 61 design requirements applicable to RWCU are as follows: Capability to permit inspection and testing of components important to safety Appropriate shielding for radiation protection Appropriate containment, confinement and filtering systems The important to safety components of the RWCU system are not part of the proposed system reclassification. Inspection and testing of the safety related components GO2-16-112
Page 14 of 17 continues to be managed as part of the inservice inspection (ISI) and inservice testing (IST) programs and technical specification surveillances. The overall shielding design of the radwaste building is not impacted by the proposed reclassification and continues
to provide shielding adequate to maintain dose limits within 10 CFR 20 and 10 CFR 50
limits.Appropriate containment and confinement is provided to minimize the probability of releasing radiological materials. Radioactive waste materials from the system are transferred to the radioactive waste management systems. 6. No Significant Hazards Consideration The proposed amendment would allow for the low temperature portions of the reactor water cleanup (RWCU) system located in the radwaste building to be reclassified from
Quality Group C to Quality Group D.Energy Northwest has evaluated whether or not a significant hazards consideration is involved with the proposed amendment(s) by focusing on the three standards set forth
in 10 CFR 50.92, "Issuance of amendment," as discussed below: 1. Does the proposed amendment involve a significant increase in the probability or consequences of an accident previously evaluated? Response: No. The proposed amendment does not result in a significant increase in the probability of an accident because Quality Group D standards are considered appropriate for
water containing components which are not part of the reactor coolant pressure boundary but may contain radioactive materials. The probability of a line break is
not increased since the materials, design, and fabrication of Quality Group C components is comparable to Quality Group D components. Differences between the two quality groups are limited primarily to quality assurance requirements. The use of Quality Group D components for portions of RWCU located in the radwaste building provides an adequate level of quality, commensurate with the importance of
the functions to be performed by that portion of the system, and ensures that the
facility can be operated without undue risk to the health and safety of the public.All safety related equipment required to mitigate accidents is either significantly remote from, or separated by protective barriers from the reclassified portions of the
system. The consequences of breaks considered in the portion of the RWCU system affected by this activity are calculated to not exceed regulatory limits for dose to control room personnel or the public.Calculated results are not significantly different than those reported for the existing instrument line break analysis in FSAR
Chapter 15.
Page 15 of 17 2. Does the proposed amendment create the possibility of a new or different kind of accident from any accident previously evaluated? Response: No.
A postulated failure in the RWCU system piping would result in a high-energy line break (HELB) accident. High energy line breaks are already postulated and analyzed at various locations for portions of the RWCU system located in the reactor building. The existing instrument line break analysis was determined to bound a postulated worst case RWCU HELB. Since the offsite and onsite consequences of a
postulated break in the reclassified portion of the RWCU is bounded by the existing instrument line break analyses, a new or different accident has not been created. 3. Does the proposed amendment involve a significant reduction in a margin of safety? Response: No.
The proposed amendment does not involve a significant reduction in a margin of safety. As noted in the technical and regulatory evaluation above, the reclassified portions of the system perform no active safety functions and will not result in
radiological safety impact beyond that already assumed within the existing plant
safety analyses.
6.1 Conclusions
The proposed change would reclassify portions of the reactor water cleanup system located in the radwaste building (including piping valves, pumps and mechanical modules) from Quality Group C to Quality Group D. Energy Northwest has reviewed the proposed change to the licensing basis and concluded that it does not involve a significant hazard consideration and will not endanger the health and safety of the
public.7. ENVIRONMENTAL CONSIDERATION A review has determined that the proposed changes would change a requirement with respect to the installation or use of a facility component located within the restricted area, as defined in 10 CFR 20. However, the proposed changes do not involve: (i) a significant hazards consideration; (ii) a significant change in the types or significant increase in the amounts of any effluents that may be released offsite; or (iii) a significant increase in individual or cumulative occupational radiation exposure.
Page 16 of 17 Accordingly, the proposed changes meet the eligibility criterion for categorical exclusion set for in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), an environmental assessment of the proposed change is not required. 8. REFERENCES 1. US NRC, Regulatory Guide 1.26 "Quality Group Classifications and Standards for Water-, Steam- and Radioactive-Waste Containing Components of Nuclear Power
Plants", Revision 3, February 1976 2. US NRC, NUREG-0892 "Safety Evaluation Report Related to the Operation of WPPSS Nuclear Project No. 2", docket no. 50-397: Washington Public Power
Supply System, December 1980 3. Letter, US NRC to ME Reddemann (Energy Northwest), Columbia Generating Station - NRC Integrated Inspection Report 05000397/2013003, dated July 25, 20134. Generic Letter 84-01, NRC Use Of The Terms "Important To Safety" and "Safety Related" , January 5, 1984 5. US NRC, Regulatory Guide 1.29 "Seismic Design Classification", Revision 3, September 1978 6. Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition - Design of Structures, Components, Equipment, and Systems (NUREG-0800, BTP 3-3 Protection Against Postulated Piping Failures in Fluid Systems Outside Containment, Rev 3, March 2007) 7. Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition - Design of Structures, Components, Equipment, and Systems (NUREG-0800, Chapter 5, Section 5.4.8 Reactor Water Cleanup System (BWR), Rev 3, March 2007) 8. Standard Review Plan for the Review of Safety Analysis Reports for Nuclear Power Plants: LWR Edition - Design of Structures, Components, Equipment, and
Systems (NUREG-0800, Chapter 3, Section 3.2.2 System Quality Group Classifications, Draft Rev 3, August 2015)
Page 17 of 17 Note: This figure is a simplified system depiction for purposes of showing the boundary of the proposed reclassification and does not represent a detailed design drawing showing system features and components.
GO2-16-112 FSAR Markups C OLUMBIA G ENERATING S TATION Amendment 63 F INAL S AFETY A NALYSIS R EPORT December 2015
LDCN-13-043,15-032 1.8-17 Regulatory Guide 1.26, Revision 3, February 1976 Quality Group Classifications and Standards for Water-, Steam-, and Radioactive-Waste-
Containing Components of Nuclear Power Plants
Regulatory Guide Intent:
Regulatory Guide 1.26 describes a quality classification system for determining acceptable quality standards for important to safety components containing water, steam, or radioactive material other than those components addressed in 10 CFR
50.55a.
Application Assessment:
Assessed capability in design.
Compliance or Alternate Approach Statement:
Identified NSSS scope of supply analysis, design, and/or equipment used in this facility complies with the guidance set forth in this regulatory guide.
General Compliance or Alternate Approach Assessment:
The definition of quality group classifications for this plant was made initially and recorded in the Preliminary Safety Analysis Report (PSAR) in accordance with ASME
Boiler and Pressure Vessel Code (B&PV), Sections III and VIII. Quality group classifications were maintained during design and construction and are actively
maintained during plant operations and modifications commensurate with the safety functions performed by the safety-related components.
This regulatory guide is applicable to Quality Groups B through D pressure parts including piping, pumps, valves, and vessels. Section
3.2 shows
the quality groups classifications of these parts.
Specific Evaluation
Reference:
See Section 3.2.
N ote: Classification of the RWCU system in the Radwaste Building takes exception to Reg. Guide 1.26. Piping, pumps, valves, and supports of the RWCU system in the Radwaste b uilding have been reclassified as Quality Group D, taking exception to the Reg. Guide 1.26 recommended classification of
Quality Group C.
C OLUMBIA G ENERATING S TATION Amendment 60 F INAL S AFETY A NALYSIS R EPORT December 2009
LDCN-07-038 3.2-2 Seismic qualification of Seismic Category I instrumentation and 3.10 electrical equipment
All SSCs not analyzed under the loading conditions of the SSE and OBE are classified Seismic Category II. Where applicable, the seismic loading conditions as determined from the Uniform Building Code are used for the design of Seismic Category II SSCs.
The OBE, as defined in 10 CFR Part 100, Appendix A, is not incorporated as part of the seismic classification scheme.
The seismic classification indicated in Table 3.2-1 meets the requirements of NRC Regulatory Guide 1.29, Revision 3, except as otherwise noted in the table.
Seismic Category 1M classification denotes systems, structures or components that are
designed and constructed to comply with position C.2 of Regulatory Guide 1.29.
3.2.2 SYSTEM
QUALITY GROUP CLASSIFICATIONS
System quality group classifications, as defined in NRC Regulatory Guide 1.26, Revision 3, are determined for each water, steam, or radioactive waste containing component of those
applicable fluid systems relied on to ensure
- a. The integrity of the RCPB,
- b. The capability to shut down the reactor and maintain it in a safe shutdown condition, or
- c. The capability to prevent or mitigate the consequences of accidents which could result in potential offsite exposure comparable to the exposure limits of 10 CFR Part 50.67.
The quality group classifications for systems and components which meet these definitions are
shown in Table 3.2-1. System quality group classifications, as indicated in Tables 3.2-1 and 3.2-2, meet the requirements of 10 CFR 50.55a and Regulatory Guide 1.26, Revision 3.
3.2.3 SAFETY
CLASSIFICATIONS
Structures, systems, and components were classified as Safety Class 1, Safety Class 2, Safety Class 3, or General Class G in accordance with the ANS-22 definition of their importance to nuclear safety (ANS-22 became ANSI/ANS-52.1-1983). Recognizing that components within
- Note: Classification of the RWCU system in the Radwaste
Building takes exception to Reg. Guide 1.26. Piping, pumps, valves, and supports of the RWCU system in the Radwaste b uilding have been reclassified as Quality Group D, taking exception to the Reg. Guide 1.26 recommended classification of
Quality Group C.
C OLUMBIA G ENERATING S TATION Amendment 58 F INAL S AFETY A NALYSIS R EPORT December 2005
3.2-7 3.2.6 IDENTIFICATION OF SAFETY-RELATED SYSTEMS AND COMPONENTS ON FLOW DIAGRAMS AND IN THE MASTER EQUIPMENT LIST
The system classification are shown on the flow diagrams using symbols code group A, B, C, D, D+; Seismic Category I, II; and Quality Class I, II, II+, and G. The Master Equipment List (MEL) uses arabic number designators for quality class and seismic category. The following is a comparison of the classification designators:
Flow Diagram Table 3.2-1 MEL Code Group A Quality Group A Code Group B Quality Group B Code Group C Quality Group C Code Group D Quality Group D Code Group D+ Quality Group D+
Seismic Category I Seismic Category I* Seismic Category 1*
Seismic Category 1M*
Seismic Category II Seismic Category II* Seismic Category 2*
Quality Class I Quality Class I Quality Class 1 Quality Class II Quality Class II Quality Class 2 Quality Class II+ Quality Class II+ Quality Class A Quality Class G Quality Class G Quality Class G
Flow diagrams which include the seismic and code classifications assigned to each piping
system are identified in Table 3.2-1. The flow diagrams delineate the boundary of seismic and code classifications for each system and present the as-built classifications. For the appropriate quality class of specific components, refer to the MEL. In some instances, these classifications reflect voluntary upgrades which may exceed Regulatory Guide 1.26, Revision 3, requirements. For inservice inspection requirements, the appropriate levels of
inspection are given in Sections 5.2.4 and 6.6.
- Table 3.2-1 may indicate Seismic Category I, 1M or II. Clarification of the Seismic 2 over 1 (i.e., 1M) support/mounting requirements is specified in the notes and/or MEL (see
Table 3.2-1
).
- Note: Classification of the RWCU system in the Radwaste Building takes exception to Reg.
Guide 1.26. Piping, pumps, valves, and supports of the RWCU system in the Radwaste building
have been reclassified as Quality Group D, taking exception to the Reg. Guide 1.26
recommended classification of Quality Group C.
Table 3.2-1 Equipment Classification (Continued)
Principal Component a Scope of Supply b Safety Class c Location d Quality Group Classification e Quality Class f Seismic Category g Notes h C OLUMBIA G ENERATING S TATION Amendment 63 F INAL S AFETY A NALYSIS R EPORT December 2015 LDCN-15-008 3.2-15 Piping and valves forming part of containment boundary P 2 C,R B I I Piping and valves forming part of secondary containment P 3 R C,D I,II+ I 36 Piping, other P G W D+ II+ II Pumps GE/P G W D+ II+ II Valves, flow control and filter system GE/P G W D+ II+ II Valves, other P G W D+ II+ II Mechanical modules GE/P G W D+ II+ II Radioactive equipment and floor drains and other radwaste piping and valves upstream of collector tanks P G R,T,W D+ II+ II 4 Instrumentation and control boards GE/P G W N/A II+ II Concentrator GE G W D+ II+ II Plant discharge line GE/P G W D II II 15 18. Reactor water cleanup system (Figure 5.4-22) Vessels, filter/demineralizer GE G W C II II Heat exchangers GE G R C II II Piping, within outermost isolation valves P 1 C A I I 2 Piping, beyond outermost containment isolation valves P G R,W C,D,D+ II,II+ II 2,4 Pumps GE G R,W C,D+ II,II+ II 2,4 Valves, isolation valves reactor coolant pressure boundary P/GE 1 C,R A I I 2 Valves, beyond outermost containment isolation valves GE/P G R,W C,D+ II,II+ II 2,4 Mechanical modules GE G R,W C,D+ II,II+ II 4 19. Fuel pool cooling and cleanup system (Figures 9.1-6.1 and 9.1-6.2
) a. Cooling Vessels P 3 R C II I Heat exchangers P 3 R C II I 16 Piping P 3 R C II I 17 Pumps P 3 R C II I 18 Makeup system (normal) P G R C II II 4,19