ML063450073
| ML063450073 | |
| Person / Time | |
|---|---|
| Site: | Point Beach  |
| Issue date: | 02/15/2007 |
| From: | Lyon C NRC/NRR/ADRO/DORL/LPLIII-1 |
| To: | Koehl D Nuclear Management Co |
| F. Lyon LPLE X2296 | |
| Shared Package | |
| ML063450067 | List: |
| References | |
| TAC MD3380, TAC MD3381 | |
| Download: ML063450073 (15) | |
Text
February 15, 2007 Mr. Dennis L. Koehl Site Vice President Point Beach Nuclear Plant Nuclear Management Company, LLC 6610 Nuclear Road Two Rivers, WI 54241-9516
SUBJECT:
POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 - ISSUANCE OF AMENDMENTS RE: CORE ALTERATIONS (TAC NOS. MD3380 AND MD3381)
Dear Mr. Koehl:
The Commission has issued the enclosed Amendment No. 224 to Renewed Facility Operating License No. DPR-24 and Amendment No. 230 to Renewed Facility Operating License No.
DPR-27 for the Point Beach Nuclear Plant, Units 1 and 2, respectively. The amendments consist of changes to the Technical Specifications (TSs) in response to your application dated October 23, 2006.
These amendments revise the TSs to eliminate the use of the defined term CORE ALTERATIONS. These amendments incorporate changes reflected in Technical Specifications Task Force (TSTF) 471-T, Revision 1, Eliminate use of term CORE ALTERATIONS in ACTIONS and Notes, and make additional changes from TSTF-51-A, Revision 2, Revise containment requirements during handling irradiated fuel and core alterations.
A copy of our related safety evaluation is also enclosed. The Notice of Issuance will be included in the Commission's biweekly Federal Register notice.
Sincerely,
/RA/
Carl F. Lyon, Project Manager Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation Docket Nos. 50-266 and 50-301
Enclosures:
- 1. Amendment No. 224 to DPR-24
- 2. Amendment No. 230 to DPR-27
- 3. Safety Evaluation cc w/encls: See next page
Pkg: ML063450067: Amend: ML063450073 TS: ML070510312 OFFICE LPL3-1/PM LPL3-1/LA SPWB/BC EICB/BC ITSB/BC NAME FLyon:ca THarris* JNakoski AHowe TKobetz DATE 12/14/06 12/14/06 1/17/07 1/19/07 1/25/07 OFFICE OGC LPL3-1/BC NAME JRund PMilano for LRaghavan DATE 2/6/07 2/15/07 Point Beach Nuclear Plant, Units 1 and 2 cc:
Jonathan Rogoff, Esquire Mr. Jeffery Kitsembel Vice President, Counsel & Secretary Electric Division Nuclear Management Company, LLC Public Service Commission of Wisconsin 700 First Street P.O. Box 7854 Hudson, WI 54016 Madison, WI 53707-7854 Mr. F. D. Kuester Nuclear Asset Manager President & Chief Executive Officer Wisconsin Electric Power Company WE Generation 231 West Michigan Street 231 West Michigan Street Milwaukee, WI 53201 Milwaukee, WI 53201 Michael B. Sellman Regulatory Affairs Manager President and Chief Executive Officer Point Beach Nuclear Plant Nuclear Management Company, LLC Nuclear Management Company, LLC 700 First Street 6610 Nuclear Road Hudson, MI 54016 Two Rivers, WI 54241 Douglas E. Cooper Mr. Ken Duveneck Senior Vice President & Chief Nuclear Town Chairman Officer Town of Two Creeks Nuclear Management Company, LLC 13017 State Highway 42 700 First Street Mishicot, WI 54228 Hudson, WI 54016 Chairman Site Director of Operations Public Service Commission Nuclear Management Company, LLC of Wisconsin 6610 Nuclear Road P.O. Box 7854 Two Rivers, WI 54241 Madison, WI 53707-7854 Regional Administrator, Region III U.S. Nuclear Regulatory Commission Suite 210 2443 Warrenville Road Lisle, IL 60532-4351 Resident Inspector's Office U.S. Nuclear Regulatory Commission 6612 Nuclear Road Two Rivers, WI 54241 November 2005
NUCLEAR MANAGEMENT COMPANY, LLC DOCKET NO. 50-266 POINT BEACH NUCLEAR PLANT, UNIT 1 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 224 License No. DPR-24
- 1. The Nuclear Regulatory Commission (the Commission) has found that:
A. The application for amendment by Nuclear Management Company, LLC (the licensee), dated October 23, 2006, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (I) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
- 2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 3.B of Renewed Facility Operating License No. DPR-24 is hereby amended to read as follows:
B. Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 224, are hereby incorporated in the renewed operating license. NMC shall operate the facility in accordance with Technical Specifications.
- 3. This license amendment is effective as of the date of issuance and shall be implemented within 30 days of the date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
Patrick D. Milano, Acting Chief Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications and Facility Operating License Date of issuance: February 15, 2007
NUCLEAR MANAGEMENT COMPANY, LLC DOCKET NO. 50-301 POINT BEACH NUCLEAR PLANT, UNIT 2 AMENDMENT TO RENEWED FACILITY OPERATING LICENSE Amendment No. 230 License No. DPR-27
- 1. The Nuclear Regulatory Commission (the Commission) has found that:
A. The application for amendment by Nuclear Management Company, LLC (the licensee), dated October 23, 2006, complies with the standards and requirements of the Atomic Energy Act of 1954, as amended (the Act), and the Commission's rules and regulations set forth in 10 CFR Chapter I; B. The facility will operate in conformity with the application, the provisions of the Act, and the rules and regulations of the Commission; C. There is reasonable assurance (I) that the activities authorized by this amendment can be conducted without endangering the health and safety of the public, and (ii) that such activities will be conducted in compliance with the Commission's regulations; D. The issuance of this amendment will not be inimical to the common defense and security or to the health and safety of the public; and E. The issuance of this amendment is in accordance with 10 CFR Part 51 of the Commission's regulations and all applicable requirements have been satisfied.
- 2. Accordingly, the license is amended by changes to the Technical Specifications as indicated in the attachment to this license amendment, and paragraph 3.B of Renewed Facility Operating License No. DPR-27 is hereby amended to read as follows:
B. Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 230, are hereby incorporated in the renewed operating license. NMC shall operate the facility in accordance with Technical Specifications.
- 3. This license amendment is effective as of the date of issuance and shall be implemented within 30 days of the date of issuance.
FOR THE NUCLEAR REGULATORY COMMISSION
/RA/
Patrick D. Milano, Acting Chief Plant Licensing Branch III-1 Division of Operating Reactor Licensing Office of Nuclear Reactor Regulation
Attachment:
Changes to the Technical Specifications and Facility Operating License Date of issuance: February 15, 2007
ATTACHMENT TO LICENSE AMENDMENT NO.
TO RENEWED FACILITY OPERATING LICENSE NO. DPR-24 AND LICENSE AMENDMENT NO.
TO RENEWED FACILITY OPERATING LICENSE NO. DPR-27 DOCKET NOS. 50-266 AND 50-301 Replace the following pages of the Facility Operating Licenses and Appendix A Technical Specifications with the attached revised pages. The revised pages are identified by amendment number and contain marginal lines indicating the areas of change.
REMOVE INSERT Unit 1 License Page 3 Unit 1 License Page 3 Unit 2 License Page 3 Unit 2 License Page 3 1.1-2 1.1-2 3.3.5-1 3.3.5-1 3.3.5-2 3.3.5-2 3.3.5-3 3.3.5-3 3.7.9-1 3.7.9-1 3.9.1-1 3.9.1-1 3.9.2-1 3.9.2-1 3.9.6-1 3.9.6-1
D. Pursuant to the Act and 10 CFR Parts 30, 40 and 70, NMC to receive, possess and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument calibration or associated with radioactive apparatus or components; and E. Pursuant to the Act and 10 CFR Parts 30 and 70, NMC to possess such byproduct and special nuclear materials as may be produced by the operation of the facility, but not to separate such materials retained within the fuel cladding.
- 4. This renewed operating license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations: 10 CFR Part 20, Section 30.34 of 10 CFR Part 30, Section 40.41 of 10 CFR Part 40, Sections 50.54 and 50.59 of 10 CFR Part 50, and Section 70.32 of 10 CFR Part 70; and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified below:
A. Maximum Power Levels NMC is authorized to operate the facility at reactor core power levels not in excess of 1540 megawatts thermal.
B. Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 224, are hereby incorporated in the renewed operating license. l NMC shall operate the facility in accordance with Technical Specifications.
C. Spent Fuel Pool Modification The licensee2 is authorized to modify the spent fuel storage pool to increase its storage capacity from 351 to 1502 assemblies as described in licensees application dated March 21, 1978, as supplemented and amended. In the event that the on-site verification check for poison material in the poison assemblies discloses any missing boron plates, the NRC shall be notified and an on-site test on every poison assembly shall be performed.
2 Reference to the licensee in License Conditions 4.C, 4.E and 4.H refers to Wisconsin Electric Power Company and is maintained for historical purposes.
Renewed License No. DPR-24 Amendment No. 224
C. Pursuant to the Act and 10 CFR Parts 30, 40 and 70, NMC to receive, possess and use at any time any byproduct, source, and special nuclear material as sealed neutron sources for reactor startup, sealed source for reactor instrumentation and radiation monitoring equipment calibration, and as fission detectors in amounts as required; D. Pursuant to the Act and 10 CFR Parts 30, 40 and 70, NMC to receive, possess and use in amounts as required any byproduct, source or special nuclear material without restriction to chemical or physical form, for sample analysis or instrument calibration or associated with radioactive apparatus or components; and E. Pursuant to the Act and 10 CFR Parts 30 and 70, NMC to possess such byproduct and special nuclear materials as may be produced by the operation of the facility, but not to separate such materials retained within the fuel cladding.
- 4. This renewed operating license shall be deemed to contain and is subject to the conditions specified in the following Commission regulations: 10 CFR Part 20, Section 30.34 of 10 CFR Part 30, Section 40.41 of 10 CFR Part 40, Sections 50.54 and 50.59 of 10 CFR Part 50, and Section 70.32 of 10 CFR Part 70; and is subject to all applicable provisions of the Act and to the rules, regulations, and orders of the Commission now or hereafter in effect; and is subject to the additional conditions specified below:
A. Maximum Power Levels NMC is authorized to operate the facility at reactor core power levels not in excess of 1540 megawatts thermal.
B. Technical Specifications The Technical Specifications contained in Appendices A and B, as revised through Amendment No. 230, are hereby incorporated in the renewed operating license. l NMC shall operate the facility in accordance with Technical Specifications.
C. Spent Fuel Pool Modification The licensee2 is authorized to modify the spent fuel storage pool to increase its storage capacity from 351 to 1502 assemblies as described in licensees application dated March 21, 1978, as supplemented and amended. In the event that the on-site verification check for poison material in the poison assemblies discloses any missing boron plates, the NRC shall be notified and an on-site test on every poison assembly shall be performed.
2 Reference to the licensee in License Conditions 4.C and 4.E refers to Wisconsin Electric Power Company and is maintained for historical purposes.
Renewed License No. DPR-27 Amendment No. 230
SAFETY EVALUATION BY THE OFFICE OF NUCLEAR REACTOR REGULATION RELATED TO AMENDMENT NO. 224 TO RENEWED FACILITY OPERATING LICENSE NO. DPR-24 AND AMENDMENT NO. 230 TO RENEWED FACILITY OPERATING LICENSE NO. DPR-27 NUCLEAR MANAGEMENT COMPANY, LLC POINT BEACH NUCLEAR PLANT, UNITS 1 AND 2 DOCKET NOS. 50-266 AND 50-301
1.0 INTRODUCTION
By application to the U.S. Nuclear Regulatory Commission (NRC, Commission) dated October 23, 2006, the Nuclear Management Company, LLC (the licensee), requested changes to the Technical Specifications (TSs) for the Point Beach Nuclear Plant, Units 1 and 2.
The proposed changes would revise the TSs to eliminate the use of the defined term CORE ALTERATIONS. These proposed amendments incorporate changes reflected in Technical Specifications Task Force (TSTF) 471-T, Revision 1, Eliminate use of term CORE ALTERATIONS in ACTIONS and Notes, and make additional changes from TSTF-51-A, Revision 2, Revise containment requirements during handling irradiated fuel and core alterations.
2.0 REGULATORY EVALUATION
2.1 Background
In TS 1.1, Definitions, the term CORE ALTERATION is defined as CORE ALTERATION shall be the movement of any fuel, sources, or reactivity control components, within the reactor vessel with the vessel head removed and fuel in the vessel. Suspension of CORE ALTERATIONS shall not preclude completion of movement of a component to a safe position.
2.2 Proposed TSs Changes The licensee proposes the following specific changes to the TSs:
- a. TS 1.1, Definitions, delete the definition of the term CORE ALTERATION.
- b. TS 3.3.5, Control Room Emergency Filtration System (CREFS) Actuation Instrumentation, delete Required Action B.1, which results in the renumbering of subsequent Required Actions. Table 3.3.5-1, delete Note (b).
Delete Required Action B.1, which results in the renumbering of subsequent Required Actions.
- d. TS 3.9.1, Boron Concentration, delete Required Action A.1, which results in the renumbering of subsequent Required Actions.
- e. TS 3.9.2, Nuclear Instrumentation, delete Required Action A.1, which results in the renumbering of subsequent Required Actions.
- f. TS 3.9.6, Refueling Cavity Water Level, delete Applicability statement During CORE ALTERATIONS, except during latching and unlatching of control rod drive shafts.
Delete Required Action A.1, which results in the renumbering of Required Action A.2.
The licensee also proposes changes to the TS Bases consistent with the proposed changes to the TSs and the elimination of the use of the defined term Core Alterations.
In its application, the licensee stated that suspending core alterations has no effect on the initial conditions or mitigation of any design-basis accident (DBA) or transient. TSTF-471 removed the defined term Core Alterations from the TSs. The NRC approved the initial (lead plant application) request for approval for TSTF-471-T from the industry on September 21, 2006 (Calvert Cliffs Nuclear Power Plant; ADAMS Accession No. ML062640492).
The NRC previously approved TSTF-51 on November 1, 1999, which eliminated the use of the term Core Alterations from certain TS Applicability Statements and Required Actions. TSTF-51 allowed some engineered safety feature systems and components to be non-operable when moving irradiated fuel, subject to a defined decay period and acceptable shutdown administrative controls.
2.3 Regulatory Requirements The Commissions regulatory requirements related to the contents of TSs are set forth in Section 50.36 of Part 50 of Title 10 of the Code of Federal Regulations (10 CFR 50.36), which assures the TS specified limiting condition for operations (LCOs) are consistent with assumed values of the initial conditions in the licensees safety analyses. Section 50.36(c)(2)(ii)(B) requires an LCO in the TS for an operating restriction that is an initial condition of a DBA. In this regard, the LCOs specify the minimum requirements for ensuring safe operation. The TS LCOs also contain associated Actions that are prescribed to be taken should certain designated conditions exist such that the LCO requirements are not met.
General Design Criterion (GDC) 19, Control room, of Appendix A to 10 CFR Part 50, provides requirements for maintaining a habitable control room and includes limitations on radiological dose that may be received by control room operators.
GDC 61, Fuel storage and handling and radioactivity control, requires that the fuel storage and handling ... systems ... 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, [and] (3) with appropriate containment, confinement, and filtering systems.
GDC 62, Prevention of criticality in fuel storage and handling, requires that criticality be prevented by physical systems or processes.
GDC 64, Monitoring radioactivity releases, requires that the means shall be provided for monitoring the reactor containment atmosphere, effluent discharge paths, and the plant environs for radioactivity that may be released from normal operations, including anticipated operational occurrences, and from postulated accidents.
3.0 TECHNICAL EVALUATION
3.1 Accidents and Transients When the reactor vessel head is unbolted and removed, core alterations take place during operating Mode 6 (refueling operation). There are only two accidents considered during Mode 6. These are: (1) a fuel-handling accident (FHA), and (2) a boron dilution accident. An FHA is initiated by the dropping of an irradiated fuel assembly, either in the containment or in the auxiliary building. There are no mitigation actions, except for taking credit for ventilation systems to reduce the dose consequences. Thus, the suspension of core alterations, except for suspension of movement of irradiated fuel, will not prevent or impair the mitigation of an FHA.
The analysis for an FHA assumes that a fuel assembly is dropped during fuel handling in the containment or the spent fuel pool. Interlocks and procedural and administrative controls make such an event highly unlikely. However, if an assembly were damaged to the extent that one or more fuel rods were broken, the accumulated fission product gases and iodines in the fuel element gap would be released to the surrounding water. Release of the solid fission products in the fuel would be negligible because of the low fuel temperature during refueling, which greatly limits their diffusion.
A boron dilution accident is initiated by a dilution source that results in the boron concentration dropping below the value required to maintain the shutdown margin. TS 3.9.1, Boron Concentration, applies in Mode 6, and the refueling boron concentration limit is specified in the Core Operating Limits Report (COLR). This accident is mitigated by stopping the dilution.
The suspension of core alterations has no effect on the mitigation of a boron dilution accident.
Also, the control rods or fuel do not affect the initial conditions of a boron dilution accident.
Thus, the FHA and boron dilution accident are not impacted by deleting Suspend Core Alterations from TS applicability statement.
3.2 Changes to TSs TS 1.1 Definitions The licensee proposed to remove the definition for Core Alterations from TS Section 1.1. Since a TS Definition has no actions or surveillance requirements, the removal of this definition to coincide with the deletion from other TS sections is acceptable.
TS Applicability Since the assumed values of the initial conditions in the licensees safety analyses for an FHA and boron dilution accident continue to be met, the applicable conditions wherein these accidents could occur and the required operability of the associated systems are not reduced by the deletion of During Core Alterations from the Applicability of TS 3.7.9 and TS 3.9.6.
Therefore, the NRC staff finds these changes acceptable.
TS Required Actions The current TS Sections 3.3.5 and 3.7.9 require core alterations be suspended if one control room radiation actuation instrument or CREFS, as applicable, is inoperable. These systems and components would be used, in part, to mitigate the consequences of postulated events during shutdown, such as an FHA. The licensee has proposed to delete the Required Action to suspend core alterations from each of these TS sections.
Except for the actions to suspend the movement of irradiated fuel, suspending core alterations does not affect the initiation or mitigation of the postulated FHA. Since the actions to suspend the movement of irradiated fuel and to place the plant in MODE 3 within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in MODE 6 within 36 hours4.166667e-4 days <br />0.01 hours <br />5.952381e-5 weeks <br />1.3698e-5 months <br /> will remain in the TS Actions, the NRC staff finds the deletion of the required action to suspend core alterations acceptable.
TS 3.9.1 - Boron Concentration The current TS 3.9.1 requires Core Alterations be suspended if the required boron concentration is not maintained within the limit specified in the COLR. The boron concentration limit during refueling operations assures that the reactor remains subcritical during Mode 6.
The term Core Alterations is not included in the Applicability statement for this TS. However, if core alterations are being performed during Mode 6, these operations must be suspended if the required boron concentration is not maintained. Also, the TS Required Actions still require positive reactivity additions be suspended if boron concentration is not within limit. Since this action provides reasonable assurance that an accidental criticality will be avoided, the NRC staff finds the proposed deletion of the required action to suspend core alterations acceptable.
TS 3.9.2 - Nuclear Instrumentation TS 3.9.2 requires that Core Alterations be suspended if the required source range nuclear instrumentation is determined to be inoperable. The source range monitors (SRMs) are used during refueling operations to monitor the core reactivity conditions. The SRMs provide a signal to the operators of unexpected changes in core reactivity such as by a boron dilution accident
or an improperly loaded fuel assembly. These detectors are located external to the reactor vessel and detect neutrons leaking from the core. Since these instruments are the only direct means of monitoring core reactivity conditions, positive reactivity additions must be suspended immediately if the SRMs are inoperable, to preclude an accidental criticality.
The TS Required Actions still require positive reactivity additions be suspended if the required SRMs are inoperable. Since this action provides reasonable assurance that an accidental criticality will be avoided, the NRC staff finds the proposed deletion of the required action to suspend core alterations acceptable.
TS 3.9.6 - Refueling Cavity Water Level The current TS 3.9.6 requires core alteration be suspended if the refueling cavity water level is not maintained within its limit. Sufficient water is necessary to retain iodine fission product activity in the water in the event of an FHA. The refueling cavity water level is credited in the safety analysis for an FHA while moving irradiated fuel assemblies. It is not credited for other situations involving core alterations. This requirement imposes an administrative burden on the operators, who have to verify that the water level meets the LCO requirement. The administrative burden of tracking water levels and responding to a change in the water level during Core Alterations has no benefit in the safety analyses, and other controls are in place for safe operation.
Since the requirement to suspend movement of irradiated fuel assemblies within containment if the refueling cavity water level is not met will remain, the suspension of core alterations does not affect the initiation or mitigation of an FHA. Therefore, the NRC staff finds the proposed change acceptable.
TS Bases The licensee also proposes changes to the TS Bases consistent with the proposed changes to the TSs and the elimination of the use of the defined term Core Alterations. The staff has no objections to the proposed changes.
Summary The NRC staff has reviewed the proposed TS changes and finds that elimination of the term Core Alterations from TSs will facilitate the refueling operations during Mode 6. It will provide operational flexibility to operators during Core Alterations activities. Since the requirements to suspend the movement of irradiated fuel assemblies within the containment will remain, the TS Action item, Suspend Core Alterations, has no effect on the initial conditions or mitigation of any design accident or transient, and the licensee will eliminate the Required Action item from these TSs.
4.0 STATE CONSULTATION
In accordance with the Commission's regulations, the Wisconsin State official was notified of the proposed issuance of the amendments. The State official had no comments.
5.0 ENVIRONMENTAL CONSIDERATION
These amendments change a requirement with respect to the installation or use of a facility component located within the restricted area as defined in 10 CFR Part 20 or change a surveillance requirement. The staff has determined that the amendments involve no significant increase in the amounts and no significant change in the types of any effluent that may be released offsite, and that there is no significant increase in individual or cumulative occupational radiation exposure. The Commission has previously published a proposed finding that these amendments involve no significant hazards consideration and there has been no public comment on such finding (71 FR 70562). Accordingly, these amendments meet the eligibility criteria for categorical exclusion set forth in 10 CFR 51.22(c)(9). Pursuant to 10 CFR 51.22(b),
no environmental impact statement or environmental assessment need be prepared in connection with the issuance of these amendments.
6.0 CONCLUSION
The Commission has concluded, based on the considerations discussed above, that (1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed manner, (2) such activities will be conducted in compliance with the Commission's regulations, and (3) the issuance of the amendments will not be inimical to the common defense and security or to the health and safety of the public.
Principal Contributor: F. Lyon Date: February 15, 2007