ML063180306

Entergys Proposed Findings of Fact and Conclusions of Law on New England Coalitions Contention 3

ML063180306
Person / Time
Site:	Vermont Yankee File:NorthStar Vermont Yankee icon.png
Issue date:	11/07/2006
From:	Travieso-Diaz M Entergy Nuclear Operations, Entergy Nuclear Vermont Yankee, Pillsbury, Winthrop, Shaw, Pittman, LLP
To:	Atomic Safety and Licensing Board Panel
Byrdsong A T
References
50-271-OLA, ASLBP 04-832-02-OLA, RAS 12503
Download: ML063180306 (57)

Text

f,45 ENTERGY'S PROPOSED FINDINGS OF FACT AND CONCLUSIONS OF LAW November 7, 2006 DOCKETED USNRC November 7, 2006 (4:00pm)

OFFICE OF SECRETARY RULEMAKINGS AND ADJUDICATIONS STAFF UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Before the Atomic Safety and Licensingz Board In the Matter of ENTERGY NUCLEAR VERMONT YANKEE, LLC and ENTERGY NUCLEAR OPERATIONS, INC.

(Vermont Yankee Nuclear Power Station)

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Docket No. 50-27 1 ASLBP No. 04-832-02-OLA (Operating License Amendment)

ON NEW ENGLAND COALITION'S CONTENTION 3

'1epIlale 5,_c y- 051

TABLE OF CONTENTS PAGE

1.

BACKGROUND...................................................................................

2 A.

PROCEDURAL HISTORY................................................................................

2 B.

WITNESSES..............................................................................................

6

1.

Entergy Witnesses.............................................................................

6

2.

NRC Staff Witnesses..........................................................................

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3.

NEC Witness..................................................................................

10

11.

DISCUSSION OF NEC CONTENTION 3 ISSUES......................................

12 111.

FINDINGS OF FACT.........................................................................

25 A.

DEFINITION OF LARGE TRANSIENTS AND LARGE TRANSIENT TESTS..........................

25 B.

REGULATORY POSITIONS RE LARGE TRANSIENT TESTING AND BASES FOR SEEKING EXCEPTIONS............................................................................................29 C.

JUSTIFICATION FOR VY'S REQUEST FOR AN EXCEPTION To LARGE TRANSIENT TESTING. 33

1.

Information Provided by Entergy in Support of its Exception Request.................

33

2.

Bases for Staff Approval of Entergy's Exception Request...............................

33

3.

Previous Industry Experience with Large Transients at EPU Levels....................

34

4.

Absence of New Thermal-Hydraulic Phenomena.........................................

37

5.

VY Operating Experience........................

.............. 38

6.

Similarities in Plant Configuration Pre and Post EPU....................................

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7.

Analytical Predictions........................................................................

41

8.

System and Component Testing....................................

• "**'* **"............... 46

9.

Conformance with Guidance Contained in Vendor Topical Reports....................

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10. Potential Effects of Large Transient on Steam Dryer.....................................

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11. Plant Impacts and Costs due to Large Transient Testing..................................

50 D.

SUMMARY

OF FINDINGS..................

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51 IV.

CONCLUSIONS OF LAW...................................................................

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November 7, 2006

.IUNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Before the Atomic Safety and Licensing Board In the Matter of)

) Docket No. 50-271 ENTERGY NUCLEAR VERMONT)

YANKEE, LLC and ENTERGY

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ASLBP No. 04-832-02-OLA NUCLEAR OPERATIONS, INC.

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(Operating License Amendment)

(Vermnont Yankee Nuclear Power Station))

ENTERGY'S PROPOSED FINDINGS OF FACT AND CONCLUSIONS OF LAW ON NEW ENGLAND COALITION'S CONTENTION 3 Pursuant to 10 C.F.R. § 2.1209, the Atomic Safety and Licensing Board's ("Licensing Board" or "Board") Order (Granting Extension of Time to File Proposed Corrections to Transcript and Proposed Findings of Fact and Conclusions of Law) dated October 12, 2006, and its directive at the evidentiary hearing held in Newfane, Vermont on the above captioned matter (see Tr. 1609 - 10),' Applicants Entergy Nuclear Vermont Yanke e, LLC and Entergy Nuclear Operations, Inc. (collectively "Entergy") submit their proposed findings of fact and conclusions of law concerning on New England Coalition ("NEC") Contention 3 in this proceeding. This submittal is presented in the form of a decision by the Board that includes findings of fact and conclusions of law with respect to that contention.

In this filing, the notation "Tr.xxxx" denotes a reference to the page of the transcript of the evidentiary hearing.

The hearing transcript begins at page 1094.

I.

BACKGROUND A.

Procedural HistoryV On September 10, 2003, Entergy submitted an application to amend the operating license (No. DPR-28) for the Vermont Yankee Nuclear Power Station ("VY") to increase the facility's maximum authorized power level from 1593 megawatts thermal ("MWt") to 1912 MWt (extended power uprate or "EPU").2 On July 1, 2004, the Commission issued a notice of consideration of issuance of the proposed amendment and opportunity for a hearing. 69 Fed.

Reg. 39,976 (July 1, 2004).

The Department of Public Service of the State of Vermont ("DPS") and NEC submitted petit ions to intervene and requests for a hearing in response to the Commission's notice.' The DPS raised five proposed contentions; N EC submitted seven. 4 Both Entergy and the NRC Staff

("Staff') filed answers to the petitioners' hearing requests on September 29, 2004. Entergy opposed admission of all contentions by both petitioners. 5 The Staff asserted that although most of the petitioners' contentions failed to meet NRC's regulatory requirements, they had each proffered at least one contention that was not objectionable. 6 On October 21 and 22, 2004, the Board conducted a prehearing conference with the petitioners, Entergy, and the Staff in Brattleboro, Vermont, in which it heard oral argument 2Letter from Jay K. Thayer, Site Vice President, to U.S. Nuclear Regulatory Commission, Document Control Desk, "Vermont Yankee Nuclear Power Station License No. DPR-28 (Docket No. 50-27 1) Technical Specification Proposed Change No. 263 Extended Power Uprate" (Sept. 10, 2003), ADAMS Accession No. ML032580089 ("Application").

3Notice of Intention to Participate and Petition to Intervene (Aug. 30, 2004) ("DPS Petition"); Request for Hearing, Demonstration of Standing, Discussion of Scope of Proceeding and Contentions (Aug. 30, 2004)

("NEC Petition'.').

4At various points in this proceeding, both the DPS and NEC tendered additional contentions. Those were either rejected as not meeting the admissibility requirements in the Commission Rules of Practice or were ultimately dismissed. See, e~. LBP-06-14, 63 NRC 568 (2006).

5Entergy's Answer to Department of Public Service Notice of Intention to Participate and Petition to Intervene (Sept. 29, 2004); Entergy's Answer to the New England Coalition's Request for Hearing (Sept. 29, 2004).

6 NRC Staff Answer to Department of Public Service Notice of Intention to Participate and Petition to Intervene (Sept. 29, 2004); NRC Staff Answer to Request for Hearing of the New England Coalition (Sept. 29, 2004).

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• relating to the admissibility of the twelve proposed contentions and associated legal issues.

Thereafter, on November 22, 2004, the Board granted the requests for hearing of both petitioners and admitted two of the DPS and two of the NEC contentions. LBP-04-28, 60 NRC 548 (2004).

On December 22, 2004, the Board ruled that hearings on the admitted contentions would be conducted in accordance with the provisions of 10 C.F.R. Part 2, Subpart L. LBP-04-3 1, 60 NRC 686, 704-06 (2004).

In subsequent months, the parties provided discovery on the admitted contentions as required by 10 C.F.R. § 2.336. On January 12, 2005, Entergy filed a motion for a protective order seeking the establishment of procedures for the disclosure of proprietary trade secrets and commercial and financial information to the parties in the course of discovery and the imposition of restrictions on the distribution of proprietary information to authorized persons pursuant to a suitable confidentiality and non-disclosure agreement. 7 The Board issued the requested order and imposed the requirement that, in order for a party to gain access to proprietary information, the representatives of the party to whom such information would be disclosed would need to execute a Confidentiality and Non-Disclosure Agreement ("Confidentiality Agreement") whose terms were specified by the Board. Order (Protective Order Governing Non-Disclosure of Proprietary Information) (Mar. 1, 2005).

The DPS and the NRC Staff executed the required Confidentiality Agreements. NEC, however, declined to have its representatives and witnesses sign such an agreement and as a result did not receive proprietary documents during discovery.

The next phase of the proceeding commenced in March 2006, after the Staff had issued 7 Entergy's Motion for Protective Order Governing Access to and Disclosure of Trade Secrets and Confidential

• Commercial or Financial Information (Jan. 12, 2005). The motion was amended twice to reflect comments by other parties and concerns expressed by the Board. See Entergy's Amended Motion for Protective Order Governing Access to and Disclosure of Trade Secrets and Confidential Commercial or Financial Information (Jan. 18, 2005) and Entergy's Further Amended Motion for Protective Order Governing Access to and Disclosure of Trade Secrets and Confidential Commnercial or Financial Information (Feb. 7, 2005).

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its Final Safety Evaluation Report ("SER") approving the proposed EPU license amendment. 8 At that point, in accordance with scheduling orders issued pursuant to 10 C.F.R. § 2.3 32(a), time limits were set for the filing of summary disposition motions, testimony, and other submissions related to the evidentiary hearing. Initial Scheduling Order (Feb. 1, 2005); Revised Scheduling Order (Apr. 13, 2006).

On May 2, 2006, the DPS filed a notice of withdrawal and request for dismissal of its contentions. 9 In an order dated June 23, 2006, the Board granted the dismissal of DPS's contentions and its withdrawal from the proceeding. LBP-06-1 8, 63 NRC 830 (2006). The withdrawal of the DPS left in controversy only the two admitted NEC contentions (Contentions 3 and 4).

The parties submitted direct testimony and statements of position on the two NEC contentions in May 2006, and rebuttal testimony and statements of position in June 2006. In addition, the Board required the parties to file supplemental direct testimony consisting of additional documents supporting or relating to their direct testimony. Order (Regarding Submission of Supplemental Documents) (June 5, 2006).

8Safety Evaluation by the Office of Nuclear Reactor Regulation Related to Amendment No. 229 to Facility Operating License No. DPR-28, Entergy Nuclear Vermont Yankee, LLC and Entergy Nuclear Operations, Inc.,

Vermont Yankee Nuclear Power Station, Docket No. 50-27 1 (Mar. 2006) (ADAMS Accession No. ML060050028) (non-proprietary version). At the same time it released the SER, the Staff issued a "Notice of Issuance of Amendment to Facility Operating License and Final Determination of No Significant Hazards Consideration," 71 Fed. Reg. 11,682 (2006), in which it determined that "the amendment involves no significant

.hazards consideration" and accordingly the amendment could be issued and made immediately effective without awaiting completion of this proceeding. Id. at 11,683.

9' Notice of Withdrawal and Request for Dismissal of Contentions of the Vermont Department of Public Service (May 2, 2006).

4

A hearing on the two NEC contentions was scheduled for the week of September 11, 20 06. Order (Scheduling Site Visit and Evidentiary Hearing) (July 28, 2006) at 2. In August 2006, NEC withdrew its Contention 4, leaving only NEC Contention 3 to be adjudicated.'10 The evidentiary hearing on NEC Contention 3 was held on September 13 and 14, 2006."1 The hearing, which was conducted under the procedures of Subpart L of 10 C.F.R. Part 2, included incorporation into the record of the direct and rebuttal testimony of NEC Contention 3 submitted earlier by the parties and the admission into evidence of the exhibits proffered by each party. 12Examination of the witnesses was conducted by the Board, but the parties had an opportunity before the hearing to submit proposed questions for the Board to consider propounding to the witnesses pursuant to 10 C.F.R. § § 2.1207(a)(3)(i) and (ii). Revised Scheduling Order, supra, at 4. At the end of the examination of all witnesses, the parties were given an opportunity to propose additional questions for the Board to consider asking the witnesses to follow up on the examination answers. Tr. 1553-54. Questions were proposed by all parties and, after consideration, the Board posed some of those questions to the witnesses. Tr.

1554-78. The hearing also included a proprietary session, which was only attended by those 10 New England Coalition's Notice of Withdrawal of its Contention Regarding Inadequate Analysis of the Vermont Yankee Alternate Cooling System Performance under Conditions of Extended Power Uprate (Aug. 10, 2006).

"On September 12, 2006, the day before the start of the evidentiary hearing, the Board and representatives of the parties visited the VY plant to view some of the physical facilities and equipment which are the subject of NEC Contention 3. Tr. 11I10.

12 Testimony of Craig J. Nichols and Jose L. Casillas on NEC Contention 3 - Large Transient Testing.(May 17, 2006) ("Entergy Dir."), Tr. 1175; Rebuttal Testimony of Craig J. Nichols and Jose L. Casillas on NEC Contention 3 - Large Transient Testing (Jun. 14, 2006) ("Entergy Reb."), Tr. 1177; NRC Staff Testimony of Richard B. Ennis, Steven R. Jones, Robert L. Pettis, Jr., George Thomas, and Zeynab Abdullahi Concerning NEC Contention 3 (May 17, 2006) ("Staff Dir."), Tr. 1383; Prefiled Written Testimony of Dr. Joram Hlopenfeld Regarding Contention 3 (May 17, 2006) ("NEC Dir."), Tr. 15 10. Entergy introduced into evidence thirty-nine exhibits, numbered Entergy Exhibits ("Entergy Exh.") 1-39 (Tr. 1149-73); exhibits 29 through 37 are proprietary. The Staff introduced into evidence eleven exhibits, with Staff Exh. 1 being proprietary. The admitted exhibits were Staff Exhs. 1, 2, 4, 5, 9-11, and 17-20. Tr. 1363-73. The remaining Staff exhibits were withdrawn as duplicative of admitted Entergy exhibits. Proposed Staff Exhs. 3 1 and 32 were not admitted. Tr.

1123-24, 1374. NEC proffered no exhibits.

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parties, their witnesses and representatives who had executed the Confidentiality Agreement. Tr.

1579-1607. NEC was excluded from the session at the evidentiary hearing where proprietary information was discussed. Order (Site Visit and Evidentiary Hearing Administrative Matters)

(Aug. 24, 2006) at 6-7; New England Coalition's List of Representatives and Witnesses for Evidentiary Hearing (Sept. 6, 2006); Tr. 1120, 1557.

Through the prefiled written testimony of the witnesses and their extensive examination by the Board at the evidentiary hearing, a thorough record was compiled that provides a sufficient basis for the findings of fact and conclusions of law set forth herein.

B.

Witnesses 1.

Entergy Witnesses Entergy's witnesses were Mr. Craig Nichols, who addressed large transient testing and experiences at the Vermont Yankee Nuclear Power Station, and Mr. Jos6 Casillas, who

-addressed large-transient testing-and experiences of the global boiling-water reactor ("BWR")

community. Testimony of Craig J. Nichols and Jos6 L. Casillas on NEC Contention 3 - Large Transient Testing (inserted into the record at Tr. 1175). Mr. Nichols and Mr. Casillas also presented rebuttal testimony responding to NEC's direct testimony. Rebuttal Testimony of Craig J. Nichols and Jos6 L. Casillas on NEC Contention 3 - Large Transient Testing (inserted into the record at Tr. 1177).

At all times relevant to this hearing, Craig J. Nichols was a Project Manager for Entergy Nuclear Operations, Inc. - Vermont Yankee. He received a Bachelor's of Science Degree in Electrical Engineering from Northeastern University and has over 23 years of experience at nuclear generating stations, including management of plant maintenance. Mr. Nichols was employed at Vermont Yankee for over 20 years. For the four years preceding the hearing, Mr.

Nichols served as the Project Manager for the Vermont Yankee Extended Power Uprate.

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Jos6 L. Casillas is a Consulting Engineer in BWR Plant Performance with GE Nuclear Energy. He received a Bachelor's of Science Degree in Mechanical Engineerin g from University of California - Davis. He has worked for GE for over 32 years, in positions including Technical Leader, Plant Performance Engineering; Technical Leader, Reload Nuclear Engineering; and Project Manager, Shroud Cracking Safety Evaluations. For the past 4 years, Mr. Casillas has served as a Plant Performance Consulting Engineer.

Entergy witness Mr. Casillas is qualified as an expert in the analysis and prediction of the performance of BWVRs in the event of large transients from EPU conditions, the operating histories of BWRs implementing EPUs, the development and characteristics of computer codes to analyze BWR response. to large transients, and the anticipated response of VY should large transient tests be conducted at that plant from EPU conditions. Enter gy witness Mr. Nichols is qualified as an expert in the operating history of VY, the modifications made to VY to implement an EPU, the performance of VY under large transients, and the anticipated response of VY should large transient tests be conducted at that plant from EPU conditions.

2.

NRC Staff Witnesses The NRC's witness panel included Richard B. Ennis, who testified regarding the review process for the Vermont Yankee Extended Power Uprate application; Steven R. Jones, who testified regarding the technical evaluation of extended power uprate requests; Robert L. Pettis, Jr., who testified regarding the Staff s review of Vermont Yankee's request to waive the large transient testing requirement in the extended power uprate application; George Thomas, who testified regarding the performance of BWRs under transient conditions; and Zeynab Abdullahi, who testified regarding the Staff s decision to grant the large transient testing waiver request, including the extent to which the Staff relied on the ODYN code. NRC Staff Testimony of Richard B. Ennis, Steven R. Jones, Robert L. Pettis Jr., George Thomas, and Zeynab Abdullahi Concerning NEC Contention 3 (inserted into the record at Tr. 1383).

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Richard B. Ennis is a Senior Project Manager in the Division of Operating Reactor Licensing, NRC Office of Nuclear Reactor Regulation, Rockville, Maryland. Mr. Ennis has a Bachelor of Science degree in Electrical Engineering from Bucknell University. He has over 28 years of experience in the commercial nuclear power industry, including Project Management of several comprehensive nuclear facility investigations; development of design, and licensing basis documentation; audits and design verifications of nuclear facilities; and software development, quality assurance, and verification and, validation.

Steven R. Jones is Acting Chief, Balance of Plant Branch in the NRC's Office of Nuclear Reactor Regulation, Rockville, Maryland. He received a Bachelor's of Science in Marine Engineering from the U. S. Naval Academy, and has completed graduate courses in Mechanical Engineering at the University of Maryland. In addition, Mr. Jones is a licensed Professional Engineer in the state of Maryland. Mr. Jones has 16 years of experience with the NRC, including serving as a Senior Resident Inspector for NRC Region 1; performing technical evaluations of numerous proposed changes to nuclear facilities; supervising the performance of NRC Staff technical review of Balance-of-Plant systems related to operating reactor license amendment requests (eg. power uprate license amendment requests); assisting in the development of the aging management program scope for license renewal; participating in design certification of new reactor designs; and operating experience analysis, including resolution of associated generic safety issues.

Robert L. Pettis is a Senior Reactor Engineer in the NRC's Office of Nuclear Reactor Regulation, Rockville, Maryland. He received Bachelor and Master of Science degrees in Civil Engineering from Northeastern University, and is a Registered Professional Engineer in Maryland, California, and Massachusetts. Mr. Pettis has over 30 years of experience with the commercial nuclear power industry, over 22 of which have been as an NRC technical staff member. He has significant experience in the areas of engineering management; nuclear 8

facilities audits, inspections, and design verifications; extended power uprate reviews; and software quality assurance, verification and validation. Mr. Pettis participated in the NRC Staff s review of the General Electric Licensing Topical Reports ("LTR") related to large transient testing, including review of the Constant Pressure Power Uprate LTR, and co-authored Section 14.2.1 of the Standard Review Plan, "Generic Guidelines for Extended Power Uprate Testing Programs," which provides Staff guidance on evaluating a licensee's EPU application in.

relation to the original startup testing performed at the plant under review.

George Thomas is a Reactor Engineer in the BWR Systems Branch, NRC's Office of Nuclear Reactor Regulation, Rockville, Maryland. He received a Bachelor of Science degree in Physics from Kerala (India) University, and has completed several graduate courses in Nuclear Engineering at the University of Pennsylvania. Mr. Thomas has 37 years of BWR power plant experience, including a broad range of functions related to the design, engineering, testing, operations, and evaluation of nuclear plant systems..He has participated in a wide range of testing programs at BWVR facilities, including construction, pre-operational and normal operations testing. He has also written test procedures.for BWR facilities. As an NRC Staff Senior Reviewer for BWRs, Mr. Thomas has provided review and technical advice regarding licensee applications for power uprates, license renewals, and new, advanced reactor designs.

Zeynab Abdullahi is a Senior Reactor Systems Engineer in the NRC's Office of Nuclear Reactor Regulation, Rockville, Maryland. She received a Bachelor of Science in Mechanical Engineering from the University of California and a Master of Science in Mechanical Engineering from the University of Maryland. With almost 20 years of experience as a technical analyst for the commercial nuclear power industry, Ms. Abdullahi has over 9 years of experience evaluating the technical merit of BWR licensee requests for changes to their licenses. Her work has included review of requests for extended power uprates and operation at expanded operating domains, and has focused on the impact of the proposed change to the design bases safety 9

analyses during steady state, transient and accident conditions. She has led or participated in technical audits of the analytical methods and calculations supporting generic topical report and plant-specific licensing applications, including those for VY.

Staff witnesses Messrs. Jones, Pettis, and Thomas and Ms. Abdullahi are qualified as experts in the analysis and prediction of the performance of BWRs in the event of large transients from EPU conditions, the development and characteristics of computer codes to analyze BWvR response to large transients, the operating histories of BWRs implementing EPUs, and the anticipated response of VY should large transient tests be conducted at that plant from EPU conditions. Those witnesses and Mr. Ennis are qualified as experts in the evaluation by the NRC Staff of EPU applications, including the criteria that apply to determini ng whether large transient tests from EPU conditions are required a particular facility in order to meet NRC regulatory requirements.

3.

NEC Witness NEC presented Dr. Joram Hopenfeld, Chief Executive Officer of Noverflo, Inc., as its witness. 13 Dr. Hopenfeld received his B.S., M.S. and Ph.D. degrees in engineering from the University of California at Los Angeles. His major fields of study were fluids flow, heat transfer and electrochemistry. Dr. Hopenfeld has 45 years of experience in the nuclear field, including over 18 years (1982-200 1) working at the NRC as "[pirogram manager for the resolution of various material and safety issues primarily in relation to PWR steam generators." Dec. 2005 Resume at 3. Dr. Hopenfeld's resume indicates expertise in the development of thermal hydraulic computer codes and models, but his testimony (at A4) indicates that this work was performed for pressurized water reactor ("PWR") steam generators and as such is not applicable 13 Dr. Hopenfeld's resume Was not included in his direct testimony. The testimony (at A2) references a resume included as an attachment to a Declaration of Dr. Joram Hopenfeld Sup~porting New England Coalition's Response to ENVY's Motion for Summary Disposition, dated Dec. 21, 2005 ("Dec. 2005 Resume"). The discussion that follows is based on that resume.

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to Vermont Yankee, which is a BWVR and therefore does not have steam generators.'14 Dr.

Hopenfeld also has experience in developing plant testing programs, but those programs appear to have been developed for liquid metal reactors and PWARs, and there is no indication that they would be applicable to BWRs like Vermont Yankee. Dec. 2005 Resume at 3. None of Dr.

Hopenfeld's published papers deal with BWR issues. Dec. 2005 Resume at 4-5.

Due to his lack of direct experience in the technical areas of concern in NEC Contention 3, Dr. Hopenfeld's testimony will be given less weight than that of the witnesses for Entergy and the Staff in the areas where his opinions conflict with theirs.

In its original Petition, NEC relied on the opinions of its consultant Mr. Arnold Gundersen as the basis for Contention 3. NEC Petition, Exh. D, "Declaration of Arnold Gundersen in Support of Petitioners' Contentions" (Aug. 30, 2004) ("Gundersen Declaration").

However, NEC did not offer testimony by Mr. Gundersen and did not make Mr. Gundersen available for examination by the Board. In addition, at the hearing, Dr. Hopenfeld disavowed knowledge of, or reliance upon, Mr. Gundersen's Declaration. Tr. 1512-13 (Hopenfeld).

Therefore, Mr. Gundersen's opinions are not part of the evidence in this proceeding.' 5 14 Dr. Hopenfeld's direct testimony asserts that "[t]he thermal hydraulic issues are common to many components both in PWRs and BWRs. For example both PWRs and BWRs use dryers to separate moisture from steam."

Hopenfeld Dir. at A5. However, Dr. Hopenfeld acknowledges that "[d]ifferences in geometry and the operating conditions would require different modeling." 14. Nowhere in his written or oral testimony has Dr. Hopenfeld provided evidence of familiarity with the specific methods and models that would be used to analyze thermal-hydraulic phenomena at BWRs in general or VY in particular.

15 In his Declaration, Mr. Gundersen asserted that (1) Entergy's citation of operational experience in the nuclear industry does not justify taking an exception to performing large transient testing for Vermont Yankee at EPU conditions, Gundersen Declaration at 4; (2) Vermont Yankee's own experience with generator load rejections at 100% of the original licensed power level does not demonstrate that there will be adequate plant performance during transients at EPU conditions, id. at 5; (3) periodic testing of systems, structures, and components during steady-state plant operation, does not confirm performance characteristics required for appropriate transient response, id. at 5; and (4) "Entergy ignores the NRC Staff's decision in the case of the Duane Arnold EPU application," id: at 4. The first three of these issues are captured in Dr. Hopenifeld's testimony; the reference to the Staff "decision" in the Duane Arnold proceeding was rejected by the Board as not controlling herein. LPB-04-28, 60 NRC at 572 n.28.

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11.

DISCUSSION OF NEC CONTENTION 3 ISSUES The Transients at Issue The "Large Transient Testing" at issue in NEC Contention 3 is limited to the main steam isolation valve ("MSIV") closure test and the turbine generator load rejection test. 16 Findings 1.

An MSIV closure transient occurs at VY when all eight MSIVs close from full rated power.

Findings 2. In the MSIV closure transient that occurs during actual plant operations, if the MSIVs receive an isolation signal, the valves start to close. When two of the valves have reached the ninety percent open position, a SCRAM signal is issued from the MSIV position switches and a SCRAM immediately takes place. This sequence is known as a "position SCRAM." Findings 3. Because the SCRAM signal is issued before the valves are significantly closed, power is effectively shut down early in a position SCRAM and consequently there is only a slight increase in reactor pressure. That pressure increase is well within design limits. Findings 4.

An MSIV closure test is performed by issuing a signal that causes all eight MSIVs to close-from full power. Performance-of an-MSIV-closure test would lead to a position SCRAM because the test would not include defeating any of the plant's safety systems. Findings 8.

Because the MSIV closure test results in a position SCRAM, it only serves to confirmn that the signals to shut down the reactor are issued, that the safety systems respond as intended, and that the relief valves operate as expected. The test will not result in an appreciable transient.

Findings 9. An MSIV closure test replicates the tests that were performed at the initial plant startup and therefore provides no new information that is not already available from initial testing and the plant's operating experience. Findings 11. The main difference in plant response between an MSIV closure. transient from EPU conditions and the same transient from pre-EPU levels is that for the EPU power level transient it may be necessary to operate one or more 16 Also discussed herein is a "turbine trip," which is a transient whose initiation is different from that of a generator load rejection test, but which proceeds in the same manner as a generator load rejection test. Findings of Fact, mfr~g, ("Findings") 20.

12

additional safety relief valves to mitigate the pressure generated by the transient, although no spring safety valves are operated. Findings 12.

A generator load rejection trip is typically started when an electric fault or other disturbance causes the generator's electrical load to be lost. Findings 13. Upon a loss of the generator's load, the turbine control valves close quickly and energize acceleration relays that cause a SCRAM. With the turbine control valves closed, the turbine bypass valves open to release the steam that no longer goes to the turbine. Findings 14. The difference in the response to a generator load rejection transient occurring at EPU and pre-uprate power levels is that in the EPU case more steam will flow through the bypass valves to accommodate a larger amount of decay steam and a limited number of safety relief valves may open to control pressure, but no spring safety valves will open. Findings 15. A generator load rejection test would be performed by actuating the control valves, so the transient would progress as if it had occurred during normnal plant operations. The test would not include defeating operation of the bypass valves.

Findings 17.

MY successfully completed large transient testing during the power ascension phase of its initial operation. Findings 22. Performing large transient tests from full EPU power levels would not provide additional information than that obtained from startup testing or plant operational transients before EPU implementation because power level has a very small impact on the development of either transient. Findings 18. Neither the MSIV closure test nor the generator load rejection test reproduces the postulated transients to which VY is designed (MSIV closure with flux SCRAM and generator load rejection without bypass), which are more severe than those occurring during plant operations or during the tests. Findings 6, 7, 16.

Large Transient Testing Requirements The MSIV closure and generator load rejection tests are included in the NRC Staff 's Standard Review Plan ("SRP") Section 14.2.1 as among the tests to be performed by plants 13

implementing an EPU; those tests, are to be performned in a similar manner to the testing that was.

performed during initial startup testing of the plant. Findings 26. SRP 14.2.1 defines seven factors that the Staff will consider in evaluating requested exceptions to the performance, of large transient tests from EPU. Those factors are: (a) previous operating experience; (b) introduction of new thermal-hydraulic phenomena or identified system interactions; (c) facility conformance to limitations associated with analytical. analysis methods; (d) plant staff familiarization with facility operation and trial use of operating and emergency operating procedures; (e) margin reduction in safety analysis results for Anticipated Operational Occurrences; (f) guidance contained in vendor topical reports; and (g) risk implications. Findings 27. There is no priority ranking of those factors; the Staff will consider them as applicable and apply its best judgment in deciding whether to approve the exception. Id.

In determining Whether large transient tests should be required, the NRC Staff seeks to ascertain the difference or "delta" between a plant's original startup tests and those that would be conducted under EPU conditions. Findings 33. In terms of evaluating the "delta" for the VY EPU, the delta is small for generator load rejection transients because the increase in decay heat removal requirements is marginal and is significantly mitigated by the turbine bypass system.

Findings 34. With respect to MSIV closure events, the setpoint for the relief valves is not changed under EPU operations and the rest of the transient is the same, so the "delta" between the conditions under which the plant was originally tested and.EPU operation is small. Findings 35.

GE developed an approach to uprating reactor power in BWRs that does not increase the maximum reactor operating pressure, known as a "constant pressure power uprate" or "CPPU".

This approach is described in GE's CPPU Topical Report. Findings 28. Entergy's EPU was implemented following the guidelines in the CPPU Topical Report, thus it is a "constant pressure power uprate." Findings 29.

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In the CPPU Topical Report, GE proposed that large transient tests (MSIV closure and generator load rejection) not be performed for CPPUs. Findings 30. The Staff declined GE's request to grant a generic exception from performing large transient tests at plant s implementing CPPUs. Findings 3 1. However, the Staff has granted all fifteen exception requests submitted so far by applicants for EPUs without pressure increase. Findings 32. The only potential exception to this unbroken string of approvals is the proposed requirement that Browns Ferry Unit 1 perform these two tests. Browns Ferry has been shut down for twenty-five years and the licensee has made substantial modifications to the plant, so it presents a unique situation not found at VY.

Id.

Entergy 's Request for Exception to Large Transient Testing In its EPU Application, Entergy sought to be excused from performing large transient testing. Findings 36. Entergy's request for an exception addressed all but one of the factors set forth in SRP 14.2.1 (the remaining factor being inapplicable). Findings 37. Entergy's basis for requesting the exception was that, if performed, the MSI-V closure and generator load rejection tests would not confirm any new or significant aspect of performance that is not routinely demonstrated by component level testing and demonstrated through analyses. Findings 38.

In its Safety Evaluation Report for the EPU, the Staff approved Entergy's request for an exception from the performance of large transient testing. Findings 39. The approval was based on the St aff s determination that the performance of those large transient tests was not necessary to demonstrate that structures, systems and components important to safet y would perform acceptably in service. Id. This conclusion was based on the scope of the post-modification and power ascension test programs, the limited scope of physical modifications made to the plant, previous operating experience, the lack of significant new thermal-hydraulic phenomena associated with a constant pressure power uprate, conformance with limitations associated with 15

analytical analysis methods, and the absence of a significant change in the results of safety analyses. Id.

Bases for Granting Exception

1. Industry Operating Experience Industry operating experience of plants which have undergone large transients from EPU is an important contributor to the NRC Staff s decision whether large transient tests needed to be performed at VY. Findings 40. Of thirteen BWR plants similar to VY that have implemented EPUs without pressure increase, four (Hatch 1 and 2, Brunswick 2, and Dresden 3) have experienced one or more unplanned large transients from uprated power levels. Findings 42. In all cases, the plant's response to the transient has been satisfactory and no unexpected plant behavior has been experienced. Findings 43-49.

Entergy drew a comparison between VY and the Brunswick plant, pointing out that the two plants have similar design with respect to important parameters such as power density, steam relief, and bypass capacities that would affect the large transient performance of the plants, such that it is reasonable to predict that the performance of both plants in the event of a large transient during EPU operations would be substantially the same. Findings 50.

The NRC Staff endorsed the validity of Entergy's comparisons between VY and Brunswick by pointing out the similarities between the two plants in critical parameters such as SRV capacity, power density*

and bypass valve capacity and agreeing with Entergy' s inference of acceptable EPU transient behavior at VY in light of the Brunswick unplanned transient experience. Findings 5 1.

The fact that the Hatch, Brunswick, and Dresden plants, all of which are similar in design to VY, experienced no anomalous response to large transients from EPU operating levels supports the conclusion that \\JY will also respond as predicted to large transients during EPU operation. Findings 54. The operating experience of these plants, which have undergone such 16

• transients without adverse consequences, indicates that it is not necessary to subject VY to such a transient. Id.

2. Absence of New Thermal-Hydraulic Phenomenon None of the modifications that have been made to implement the power uprate at VY will introduce new thermal-hydraulic phenomena, nor are any new system interactions introduced during or as the result of analyzed transients. Findings 58. No systems were added or changed at VY that would be required to mitigate the consequences of the transients that would be the subject of the large transient tests, and there have also been no changes in the flow or heat transfer regime in the reactor core in implementing the uprate. Id.

No instances of abnormal thermal-hydraulic phenomena have been observed at any BWVRs that have implemented a CPPU, and in the six months of operation since implementation of the uprate VY has exhibited no appreciable changes in thermal-hydraulic performance.

Findings 59-60.

3. VY Operating Experience Prior to implementation of the EPU, VY experienced a number of unplanned large transients, including events in 2004 and 2005. Findings 61-65. No significant anomalies were experienced in VY's response to any of these transients. Findings 66.

The transients in 2004 and 2005 occurred after most of the modifications associated with EPU had been implemented. In each instance, the modified or added equipment functioned normally during the transient. Findings 67. The plant's performance during these recent transients, including that of the modified components, supports the conclusion that the plant will respond as designed to transients at EPU conditions. Findings 68.

17

4. Similarities in Plant Configuration The modifications that Entergy made to VY to implement the EPU had a limited scope and di d not result in the addition of any new systems that would affect the plant's response to large transients or would result in new system interactions. Findings 69. Most of the EPU modifications made at VY were to non-safety-related components, which are not credited in licensing basis transient analyses, or were incidental changes, such as alarms, indications, and scaling changes, that do not impact transient response. Findings 70. Significantly, the operating pressure was kept unchanged in the uprate, so that the performance of the plant safety systems relied upon to respond to the transients was unaffected by the uprate. Findings 7 1.

Other plants implementing constant pressure power uprates have made similar modifications and have not exhibited new thermal -hydraulic phenomena or different responses in the systems that were modified. Findings 72.

5. Analytical Predictions The large transient analyses for VY were performned using the ODYN computer code.

ODYN is a proprietary code developed by GE and approved by the NRC in 1981 for use in the analysis of GE BWR plant response to pressurization transients. Findings 73. The ODYN code features an integrated one-dimensional reactor core model which is coupled to the recirculation and major system control models. The recirculation and control systems are integrated in the code to analyze the plant's response to fast pressurization transients. ODYN also models the steamline pressure wave response in the main steam line, which includes modeling of the main turbine control valves and bypass valves. Findings 74. ODYN's simulation involves describing the physical plant in the model (i.e., volumes, flow paths, resistances), establishing the desired operating conditions (i.e., water level, power, pressure) and introducing a disturbance (i.e., valve closure, pump trip, control action). The ODYN model predicts the plant response behavior based on its physical model correlations. Findings 75.

18

The ODYN code has been benchmarked against three turbine trips conducted in the 1 970s at the Peach Bottom Unit 2 plant. The Peach Bottom turbine trip tests used to benchmark the ODYN code represented more severe conditions than those observed in actual plant transient events, in that the reactor trip was purposefully delayed to increase the severity of the transient.

Findings 76. ODYN was also benchmarked for MSJV closure transients by comparing its predictions for such a transient against the results of the MSIV test conducted during startup at the Hatch plant. Findings 77. As a code benchmarked against all significant transients, ODYN is capable of predicting accurately the plant behavior during transients occurring at EPU power levels. Findings 78.

ODYN has been approved by the NRC for application to the large transients of interest here and other plant events including loss of auxiliary power - all grid connections; feedwater controller failure - maximum demand; pressure regulator failure - closed; loss of feedwater heating; pressure regulator failure - open; recirculation flow. decrease events; recirculation flow increase events; and increase in coolant inventory events. Findings 79. The ODYN licensing code predictions bound both the Peach Bottom test data and the results of the startup large transient tests of all other BWvR plants. Findings 80.

ODYN was developed as a "best estimate" code in that it does not incorporate any deliberate conservatisms into the analytical model. However, ODYN is a one-dimensional code and includes some simplifications in going from three dimensional physical configurations to one dimension. These simplifications result in conservative biases in the model's predictions, which on the average overestimate the power and pressure levels experienced during the transients. Findings 8 1. Thus, ODYN gives conservatively high predictions of the two main

("Level 1 ") parameters of interest during MSIV closure, generator load rejection and turbine trip transients, which are reactor power and pressure. Id. ODYN also provides conservatively high predictions of other plant parameters, such as steam flow and pressure drop. Id.

19

The ODYN model has been upgraded since its introduction to include greater 'modeling detail such as increased nodes, advanced physics correlations, and more representative control systems. Findings 84. These changes have consistently improved the accuracy of the ODYN code and reduced the uncertainty in its predictions compared against the qualification tests. Id.

The current version of ODYN cuts the difference between analytical prediction and qualification test results in about half from the differences obtained with the code version used at the time ODYN was first benchmarked against.Peach Bottom test data. Findings 85.

In every instance in which unplanned large transients from EPU power levels have been experienced at BWR plants similar to \\'Y and an analysis of the scenario involved in the transients existed, the plant's response was bounded by the analyses performed using ODYN.

Since ODYN has provided adequate analytical predictions of transient performance for a variety of plants undergoing EPU, such as Hatch, it can provide similar predictions for VY. Findings 86.

A comparison of the turbine test transient performnance at the KKL plant in Switzerland against the ODYN predictions shows consistency between the test results and those predicted in the model's qualification, as well as in other comparisons between ODYN runs and plant operating data. In all cases, the ODYN model slightly overpredicts vessel peak pressure.

Findings 87.

A criticism raised by NEC witness Dr. Joram Hopenfeld against ODYN was that certain parameters in the thermal hydraulic model (the drift velocity vgj and the void distribution c,,) are inappropriate because they were deter-mined experimentally under steady state conditions and do not apply to transients. Findings 89. On the other hand, the Staff found that the critical parameter calculation from the ODYN code is neither conservative nor non-conservative, but that it predicts the available data well and within the expected uncertainty range. Findings 90.

20

It is not necessary to resolve the difference of opinion between Dr. Hopenfeld and the Staff regarding the adequacy of ODYN's thermal-hydraulic model because the ODYN analyses tend to overestimate the reactor pressures and power levels thus the errors, if they exist, do not result in nonconservative predictions of plant behavior. Findings 91. In addition, even if Dr.

Hopenfeld's criticisms of the ODYN code are accepted, their impact on the determination whether an exception to large transient testing is appropriate would be minimal, because the most important factor in making such a decision is not the accuracy of ODYN, but rather the operating experience of VY and other facilities. Id.

VY has analyzed the limiting transients for each fuel cycle using ODYN and applying plant-specific core neutronic and thermal-hydraulic conditions as inputs. Findings 92. In advance of implementation of the EPU, GE prepared in December 2005 an updated Supplemental Reload Licensing Report ("SRLR") containing analyses that predict the performance of VY under EPU conditions. The analyses reported in the SRLR included the results of licensing basis generator load rejection and MSIV closure simulations conducted using the ODYN code. Findings 93. The results of these simulations verified that: (1) these transients remain the limiting transients from the perspective of the selected parameters, and (2) the results rem.ain well within the design and license limits. Id. In addition, several VY plant transients have been compared against ODYN predictions over the years to assess the specific BW*R licensing basis. All of these comparisons have determined that the licensing predictions are bounding and that the plant equipme nt response is consistent with its design basis. Findings 94.

6. System and Component Testing Pursuant to 10 C.F.R. § 50.36, a reactor's Technical Specifications are required to include limiting conditions for operation ("LCOs") for the plant's safety related features. When an LCO is met, the associated structures, systems and components ("SSCs") are considered to be operable. Findings 95.

21

Technical Specification-required surveillance testing (L.g., component testing, trip logic system testing, simulated. actuation testing) is routinely performed at VY during plant operations.

Such testing demonstrates that the SSCs required for appropriate transient performance will perform their functions, including the integrated performance for transient mitigation that is assumed in the transient analysis. Findings 96.

At VY, the MSIVs are tested quarterly. The safety relief valves and spring safety valves are tested once every operating cycle. These valves are required to perform in accordance with the design during large transients; their periodic testing assures that their performance during large transients will be acceptable. The reactor protection system instrumentation that is relied on to mitigate large transients is tested quarterly, assuring it will carry out its safety function in the event of a large transient. Findings 97. Because the characteristics and functions of SSCs are tested periodically during plant operations, they do not need to be demonstrated further in a large transient test. Therefore, periodic testing of SSCs during steady-state plant operation can confirm performance characteristics of SSCs required for appropriate transient response.

Findings 98.

Potential Effects of Transients on Steam Dryer NEC witness Dr. Hopenfeld expressed a concern that the structural integrity of the steam dryer could be affected by the EPU because the increased flow velocity at EPU conditions increases turbulence at vortex shedding frequencies and thereby increases loads on the dryer. At the hearing, Dr. Hopenfeld testified that his concern about the impact on the steam dryer of a large transient would be that if the dryer was already weakened through repeated fatigue cycles or was suffering from stress corrosion cracking, resonant vibrations produced by the transient "would cause potential problems." Findings 100. However, Dr. Hopenfeld did not indicate that the VY steam dryer is weakened or cracked, and did not know whether resonant vibrations that could lead to damage to the dryer would result from a large transient at VY. Findings 101.

22

Flow induced vibration loads on the steam dryer are steady-state long term effects.

Findings 102. The Staff guidance on EPU testing calls for the conducting of vibration testing and monitoring of reactor vessel internals. Such testing is to be conducted under steady state conditions, not through transient testing. Id.

Determination of dynamic loadings on components is not the purpose of the large transient tests. Dynamic loadings of components under normal, upset, or faulted conditions (including transients) are covered in separate analyses and acceptance criteria. Findings 103.

Large transient testing provides information on the peak reactor vessel pressure and power level (i.e., temperature increase) resulting from the pressurization caused by the large transients, but provides no information for use in deriving either fatigue factors on the steam dryer or the loadings to which the dryer will be subjected. Findings 104.

The Safety Evaluation Report for the CPPU Topical Report discusses an acceptable methodology for evaluating the stresses on various components subject to increased loadings due to power uprate conditions for plants using the CPPU approach (such as VY). As described in CPPU SER, the loads and load combinations are evaluated for normal operation, upset (i.e.,

transient), emergency, and faulted conditions to determine if the calculated stresses and fatigue usage factors are less than the code allowable limits. Findings 105.

The analyses of the'stresses on the VY steam dryer under EPU operating conditions were conducted using methodologies described by GE in the CPPU topical report and the stresses were confirmed to be acceptable under all conditions, including transients. Findings. 107. The loadings imparted on the steam dryer by the large transients of interest are of short duration and are well within design margins. Findings 108. The pressure wave traveling through the steam lines would impinge on the dryer's front face, which at VY has been strengthened to a one inch thickness. Findings 109. For those reasons, performing large transient testing would provide no meaningful information on the critical loads on the dryer. Findings 1 10.

23

Impacts of Performing Large Transient Tests There are minimal, if any, safety risks or concerns involved in the performance of large transient tests. Findings I111. No additional plant instrumentation would need to be installed to conduct th e large transient tests. Findings 112. However, performance of large transient tests would impose additional thermal cycles on the plant's primary system. Findings 113.

Performance of large transient tests would require developing test procedures and assembling an organization to perform the tests and check the plant condition before and after the tests. There would be internal labor costs associated with planning and performing the tests, which would involve twenty to thirty plant staff people. Findings 114.

There would be significant plant availability penalties associated with performing the large transient tests. The plant would have to be offline for a minimum of two days for every test that was conducted. Findings 115. A two day outage would result in a loss of revenue to Entergy on the order of one and a half million dollars. Complications such as equipment breakdowns could extend the outage by several days. Id.

Summary of Findings The evidence presented by the parties on NEC Contention 3 demonstrates that large transient testing from full power EPU levels can be performed safely, but carrying out those tests will have adverse availability and economic consequences and will lead to an outage of the facility for at least several days. Findings 116.

On the other hand, large transient testing, if performed at VY, will not provide any additional information about the plant's response to a large transient that is not already available from the compon ent and system testing that is routinely performed at VY, from VY's pre-EPU transient performance, and from the operating experience of other similar BWRs that have undergone unanticipated large transients from EPU levels. Findings 117. These sources of 24

information, plus the analytical predictions performed using the ODYN code, provide a high degree of confidence that the VY facility will perform satisfactorily and shut down safely in the event of a large transient (MSIV closure, generator load rejection, or turbine trip) from full EPU power levels. Id.

The concerns expressed by NEC in Contention 3 - which largely relate to the impact of a large transient on components such as the steam dryer - are not addressed by performing large transient testing because large transients do not impart bounding loads on the steam dryer and provide no information for use in deriving either fatigue factors on the steam dryer or the loadings to which the dryer will be subjected during long term plant operations. Findings 118.

Performance of large transient testing is therefore not justified on the basis of NEC's concerns, which are lacking in merit. Findings 119.

The record shows that the large transient tests addressed in NEC Contention 3 are not required to demonstrate that structures, systems and components important to safety will perform satisfactorily in service at VY under EPU conditions. Accordingly, the exception from such. tests requested by Entergy is warranted and was appropriately granted by the. Staff. Findings 120.

11I.

FINDINGS OF FACT A.

Definition of Lam~e Transients and Large Transient Tests

1. The "Large Transient Testing" at issue in NEC Contention 3 is limited to the main steam isolation valve ("MSIV") closure test and the generator load rejection test.

Memorandum an d Order (Clarifying the Scope of NEC Contention 3) (April 17, 2006),

slip op. at 3.

2.

An MSIV closure transient occurs at VY when all eight MSIVs close from full rated power. Entergy Dir. at A20. Sudden closure of all MSIVs from full power is an 25

"Abnormal Operational Transient" as described in Chapter 14 of the \\IY Updated Final Safety Analysis Report ("UFSAR"). Id.

3.

In the MSIV closure transient that occurs during actual plant operations, if the MSIVs receive an isolation signal, the valves start to close. When two of the valves have reached the ninety percent open position, a SCRAM signal is issued from the MSIV position switches and a SCRAM immediately takes place. Id. at A22; Tr. 1180-82 (Nichols). This sequence is known as a "position SCRAM." Tr. 1186 (Nichols).

4.

Because the SCRAM signal is issued before the valves are significantly closed, power is effectively shut down early in a position SCRAM and there is only a slight increase.in reactor pressure. That pressure increase is well within design limits. Tr. 1184-8 5 (Casillas); Tr. 1390-91 (Abdullahi); Tr. 1475-78 (Thomas, Abdullahi).

5. When the position SCRAM occurs, four safety relief valves (one per main steam line) open, either automatically or by actions of the plant operators, to relieve the pressure caused by the steam buildup. Tr. 1183 (Nichols). Opening of the safety relief valves will control the pressure increase in the reactor and relieve the steam. Id. At that point, the normal post-shutdown emergency core cooling systems will activate to maintain pressure control and remove decay heat. Tr. 1186-88 (Nichols); Tr. 1387-88 (Abdullahi).

6.

The design basis MSIV transient is known as a "flux SCRAM" or "delayed SCRAM."

Tr. 1192 (Nichols). In the design basis analyses, the assumption is made that the position SCRAM signals are not issued, so that the SCRAM occurs only when the local power range monitors detect high flux levels and issue a shutdown signal. Tr. 1192-93 (Nichols). As a result, the power and pressure excursions assumed to occur in the transient are much larger than would be experienced in a position SCRAM. Id. Tr.

1391-92 (Abdullahi).

26

7.

The transient produced by an MSIV closure with flux SCRAM is the most severe abnormnal operational transient from the standpoint of increase in nuclear system pressure. Entergy Dir. at A22.

8.

An MSJV closure test is performed by issuing a signal that causes all eight MSJVs to close from full power. Entergy Dir. at A20. Performance of an MSIV closure test would lead to a position SCRAM because the test would not include defeating the plant's safety systems. Tr. 1193 -94 (Nichols); Tr. 13 99-1402 (Ennis).

9.

Because the MSIV closure test results in a position SCRAM, it only serves to confirm that the signals to shut down the reactor are issued, that the safety systems respond as intended, and that the relief valves operate as expected. Entergy Dir. at A2 1; Tr. 1196 (Casillas). The test will not result in an appreciable transient. Entergy Dir. at A22.

10. The main parameters that are confirmned by the test are peak reactor pressure and power level. Tr. 1195 (Casillas). The test is not int ended to, and does not, test the maximum

.response of the primary system structures.. Id.

11. An MSIV closure test would replicate the tests that were performed at the initial plant startup and therefore would provide no new information that is not already available from initial testing and the plant's operating experience. Tr. '1196-97 (Casillas).

12. The main difference in plant response to an MSIV closure transient from EPU conditions and the same transient from pre-EPU levels is that for the EPU power level transient it may be necessary to operate one or more additional safety relief valves to relieve the pressure generated by the transient, although no spring safety valves are operated. Tr.

1210 (Casillas).

13. A generator load rejection trip is typically started when an electric fault or other disturbance causes the generator's electrical load to be lost. Tr. 1219 (Nichols).

27

14. Upon a loss of the generator's load, the turbine control valves close quickly and energize acceleration relays that cause a SCRAM.

-1d. With the turbine control valves closed, the turbine bypass valves open to release the steam that no longer goes to the turbine. Id.

15. VY has ten bypass valves that provide one of the highest bypass capacities (86%) in United States plants. Id. The difference in the response to a generator load rejection transient occurring at uprate and pre-uprate power levels is that, in the uprate case, more steam will flow through the bypass valves to accommodate a larger amount of decay steam and a limited number of safety relief valves may open to control pressure, but no spring safety valves will open. Tr. 1220 (Nichols).

16. The design basis generator load rejection transient is one in which the bypass valves are assumed not to open, causing a far more severe transient than is experienced during plant operations. Tr. 1222 (Nichols). Such a postulated design basis transient provides a bounding challenge to the fuel thermal limits.. Entergy Dir. at A24.

17.--A-generator load rejection-test would-be-performed-by-actuating the control valves, so that the transient would progress as if it occurred during normal plant operations. Tr.

1262 (Nichols). No attempt would be made to defeat operation of the bypass valves to replicate the bounding design basis transient. Tr. 1222-23, 1262-63 (Nichols).

18. Performing large transient tests from full EPU power levels does not provide additional information than that obtained from startup testing or plant operational transients before EPU implementation because power level has a very small impact on the development of either transient. Tr. 1208 (Casillas). The transients are of short duration and the parameters of interest exhibit an integrated response, allowing the mitigation systems such as the relief valves and the bypass valves to accommodate the slight increase in released energy. Tr. 1209-10 (Casillas).

28

19. In an actual transient, there are several layers of defense in depth that mitigate the effects of a large transient. In the case of an MSIV closure, for example, operation of the position SCRAM switches renders the transient mild; operator or automatically actuated safety relief valves provide pressure relief; and spring or "code" safety valves provide ultimate overpressure protection, should it be needed. Tr. 1237-3 8 (Nichols). These defense in depth mechanisms prevent the transient pressure from ever reaching the design limits. Tr. 1237-38 (Nichols).

20. A turbine trip is analogous to a generator load rejection trip. It has a different starting mechanism from a generator load rejection (closing of stop valves) but the transient proceeds in the same manner in both types of event. Tr. 1256 (Casillas).

21. Both the MSIV closure transient and the generator load rejection or turbine trip transient are short duration events, lasting approximately twenty seconds. Tr. 1258-59 (Casilla's).

The MSIV transient has a larger energy peak because the steam bypass valves are not in

-operation.-Tr. 1259-60 (ICas-illas).-The peak pressure occurs approximately eight seconds into the transient; for the generator load rejection, the peak occurs somewhat earlier (approximately five seconds after transient initiation) because the stop valves close faster than the MSI Vs. Tr. 1260 (Casillas); Tr. 1386 (Thomas).

22. VY successfully completed large transient testing during the power ascension phase of its initial operation. It performed a turbine trip test from 98% power on January 24, 1974; an MSIV closure test from 92.7% power on February 23, 1974; and a generator load rejection test on March 29, 1974 from 93.7% power. Tr. 1572 (Nichols).

B.

Regulatory Positions re Large Transient Testing and Bases for Seeking Exceptions

23. Testing requirements for plants seeking to implement an EPU are derived from 10 C.F.R. § 50.34(b)(6)(iii) and the quality assurance program that is incorporated into the 29

operating license for each reactor pursuant to 10 C.F.R. § 50.34(b)(6)(ii) and implemented pursuant to 10 C.F.R. § 50.54(a). Staff Dir. at A8.

24. NRC's Review Standard RS-001, "Review Standard for Extended Power Uprates,"

Revision 0 (December 2003), Staff Exh. 5, contains NRC regulatory guidance for EPUs.

The standard refers to Standard Review Plan Section 14.2.1 ("SRP 14.2. 1" for the testing guidelines related to extended power uprates. Id..

25. Subsection III.A, "Review Procedures," of SRP 14.2.1 provides procedures for a comparison of the proposed EPU test program to the initial plant test program.

Subsection III.B provides procedures for a review of EPU post-modification testing requirements. Table 2 to SRP Section 14.2.1 provides a generic listing of transient tests that are typically included in initial plant test programs that may be affected by modifications associated with an EPU. Staff Dir. at A8.

26. Generator load rejection and MSIV closure tests are included in Table 2 to the SRP

-- -under-the-designations--ýý'Dynamic -Response -of Plant-for-Full -L oad Rejection," and "Dynamic Response of Plant to Automatic Closure of All Main Steam Isolation Valves,"

respectively. The SRP specifies that those tests are to be performed in a similar manner to the testing that was performed during initial startup testing of the plant. SRP 14.2. 1, Entergy Exh. 4,Section III.A. 1; Entergy Dir. at A 18.

27. SRP 14.2.1 defines seven factors that the Staff will consider in evaluating requested exceptions to the performance of large transient tests from EPU. Those factors include:

(a) previous operating experience; (b) introduction of new thermnal-hydraulic phenomena or identified system interactions; (c) facility conformance to limitations associated with analytical analysis methods; (d) plant staff familiarization with facility operation and trial use of operating and emergency operating procedures; (e) margin reduction in safety analysis results for Anticipated Operational Occurrences;, (f) guidance contained 30

in vendor topical reports; and (g) risk implications. Entergy Exh. 4,Section III.C.2.

There is no priority ranking of those factors; the Staff will consider them as applicable and apply its best judgment in deciding whether to approve the exception. Tr. 1462 (Ennis).

28. GE developed an approach to uprating reactor power in BWVRs that does not increase the maximum reactor operating pressure. This approach is described in GE Licensing Topical Report NEDC-3 300P-A, Revision 4, dated July 2003, "Constant Pressure Power Uprate ("CPPU")" (Entergy Exhs. 25 and 30P) ("CPPU Topical Report").

29. Entergy's EPU was implemented following the guidelines in the CPPU Topical Report, thus it is a "constant pressure power uprate." Entergy Dir. at Al13.

30. In the CPPU Topical Report, GE proposed that large transient tests (MSIV closure and generator load rejection) not be performed for CPPUs. Entergy Exh. 30P at Section.

10.4. GE provided a generic justification for not performing these tests and concluded

-that they rne-Yot needed-to demnoastrate the-safety of plants implementing a CPPU. Id.

3 1. In its Safety Evaluation Report for the CPPU Topical Report, the Staff noted that

"[flarge transient testing is normally performed on new plants because experience does not exist to confirm a plant's operation and response to events. However, these tests are not normnally performed for plant modifications following initial startup because of well-established quality assurance and maintenance programs including component and system level post-modification testing and extensive experience with general behavior of unmodified equipment." Entergy Exh. 30P, Staff Safety Evaluation at § 10.5.3. The Staff discussed the. information that GE had provided in support of el iminating the large transient testing requirement in connection with CPPUs and concluded: "The staff has previously accepted not perform-ing these tests on a plant-specific basis. How ever, the staff is developing guidance to generically address the requirement for conducting large 31

transient tests in connection with power uprates. Therefore, the staff is not prepared at this time to accept the proposed elimination of large transient tests for CPPU." Id. at § 10.5.9.

32. While the Staff declined GE's request for generic exemption for large transient testing in connection with constant pressure power uprates, the Staff has granted all fifteen exception requests submitted so far by applicants for EPUs without pressure increase.

Tr. 1451-53 (Pettis). The only. potential exception to this unbroken string of approvals is the proposed requirement that Browns Ferry Unit 1 perform these two tests. However, Browns Ferry has been shut down for twenty five years and the licensee has made substantial modifications to the plant, so it presents a unique situation not present at VY.

Tr. 1466-69 (Jones, Abdullahi, Pettis).

33. The transient tests whose performance is recommended in SRP 14.2.1 are based on the Regulatory Guide 1.68 guidance for initial plant testing. Tr. 141 8-19 (Pettis). For

---operating-pl ants that -are -seeking-an EPU, -the Staff-seeks -to ascertain-the difference or "delta" between the plants' original startup tests and those that would be conducted under EPU conditions. Tr. 1462 (Ennis).

34. The ability of the VY turbine bypass valves to remove decay heat is greatly in excess of the decay heat that results from a generator load rejection transient. This was demonstrated when the plant responded as anticipated to a generator load rejection transient from full power that occurred in 2004. Tr. 1423-27 (Jones). Thus, for evaluating the "delta" for the VY EPU, the delta is small for generator load rejection transients because the increase in decay heat removal requirements is marginal is significantly mitigated by the turbine bypass system. Tr. 1423-25 (Jones).

35. With respect to MSIV closure events, the setpoint for the relief valves is not changed under EPU operations and the rest of the transient is the same, so the "delta" between the 32

conditions under which the plant was Originally tested and EPU operation is small. Tr.

1432-33 (Abdullahi).

C.

Justification for VY's Request for an Exception to Large Transient Testing

1.

Information Provided by Entergy in Support of its Exception Request

36. In its EPU Application, Entergy sought to be excused from performing large transient testing. Entergy Dir. at AlO0; Entergy Exh. 5.

37. Entergy's request for an exception to the performance of large transient testing at VY addressed all but one of the factors set forth in SRP 14.2. 1. Entergy's request did not address the risk implications factor because its evaluation of the tests was deterministic, so risk factors were not evaluated. Entergy Dir. at AlO,A26; Tr. 1270-72 (Nichols).

The information in support of the requested exception was presented in a series of Entergy submittals to the Staff. Entergy Exhs. 5 and 6; Staff Exhs. 9, 10 and 11.

38. Entergy's basis for requesting the exception was that, if performed, the MSIV closure and generator load rejection tests would not confirm any new or significant aspect of performance that is not routinely demonstrated by component level testing and demonstrated through analyses. Entergy Dir. at A27.

2.

Bases for Staff Approval of Entergy's Exception Request

39. In its Safety Evaluation Report for the EPU (Staff Exhs. 1 and 2), the Staff approved Entergy's request for an exception from the performance of large transient testing. Staff Exh. 2 at 271. The Staff determined that the performance of those large transient tests was not necessary to demonstrate that structures, systems and components important to safety would perform acceptably in service. This conclusion was based on the scope of the post-.modification and power ascension test programs, the limited scope of physical modifications made to the plant, previous operating experience, the lack of significant 33

new thermal-hydraulic phenomena associated with a constant-pressure power uprate, conformance with limitations associated with analytical methods, and the absence of a significant change in the results of safety analyses. Staff Dir. at AlO0.

3.

Previous Industry Experience with Large Transients at EPU Levels

40. Industry operating experience of plants undergoing large transients from EPU is the first factor listed in SRP 14.2.1 to be considered by the Staff in deciding whether to grant an exception from large transient testing. It was also an important contributor to the NRC Staff s decision whether large transient tests needed to be performed at VY. Tr. 1435 (Abdullahi).

41. Thirteen other BWRs similar to VY have implemented EPUs without pressure increase:

Hatch Units 1 and 2; Monticello; Muehleberg (KKM); Leibstadt (KKL); Duane Arnold; Dresden Units 2 and 3; Quad Cities Units I and 2; Clinton; and Brunswick Units 1 and

2. Entergy Dir. at A 15.

42. Of the thirteen BWR plants that have implemented EPUs without increased reactor operating pressure, four (Hatch I and 2, Brunswick 2, and Dresden 3) have experienced one or more unplanned large transients from uprated power levels. Entergy Dir. at A44.

43. Southern Nuclear Operating Company's ("SNOC") application for EPU of Hatch Units 1 and 2 was granted without a requirement to perform large transient testing. VY and Hatch are both BWR/4 plants with Mark I containments. Hatch Unit 2 experienced a post-EPU unplanned transient that resulted in a generator load rejection from approximately 111 % original licensed thermal power ("OLTP") (98% of uprated power) in May 1999. All systems functioned as expected and no anomalies were seen in the plant's response to this transient. Entergy Dir. at A44; SNOC's LER 1999-005-00 (Entergy Exh. 9).

34

44. Hatch 2 also experienced a post-EPU reactor trip on high reactor pressure as a result of MS1V closure (from 113%/ OLTP (100% of uprated power)) in 2001. All systems functioned as expected and designed, given the conditions experienced during the transient. Entergy Dir. at A44; SNOC's LER 2001-003-00 (Entergy Exh. 10).

45. Hatch Unit I has also experienced two post-EPU turbine trips from 112.6% and 113% of OLTP (99.7% and 100% of uprated power) as reported in SNOC LERs 2000-004-00 and 2001-002-00, respectively (Entergy Exhs. 11 and 12). Again, the behavior of the primary safety systems was as expected. No new plant behaviors for either plant were observed. Entergy Dir. at A44.

46. Progress Energy's Brunswick Units 1 and 2 were licensed to uprate their power output to 120% of OLTP without being required to perform large transient testing. Brunswick Unit 2 experienced a post-EPU unplanned transient that resulted in a generator/turbine trip due to loss of generator excitation from 115.2% OLTP (96% of uprated thermal power) in the fall of 2003. Entergy Dir. at A44. As noted in Progress Energy's LER 2003-004-00 (Entergy Exh. 13), no anomalies were experienced in the plant's response to this transient, and no unanticipated plant behavior was observed.

47. Exelon Generating Company LLC's applications for EPU for Quad Cities Units 1 and 2, and Dresden Units 2 and 3 were granted without requiring the performance of large t ransient testing. The Quad Cities and Dresden units are plants similar to V-Y, featuring Mark I containments. Entergy Dir. at A44.

48. Dresden 3 has experienced several turbine trips and a generator load rejection from high uprated power conditions. In January 2004, Dresden 3 experienced two turbine trips from 112.3% and 113.5% of OLTP (96% and 97% of uprated power) as reported in Exelon LERs 2004-001 -00 and 2004-002-00, respectively (Entergy Exhs. 14 and 15).

The plant response was as predicted in the transient analyses. Entergy Dir. at A44.

35

49. Similar plant response was observed in May 2004, when Dresden 3 also. experienced a loss of offsite power which resulted in a turbine trip on generator load rejection from 117% of OLTP (100% of uprated power). Exelon LER 2004-003 -00 (Entergy Exh. 16).

50. Entergy drew a comparison between VY and the Brunswick 1 plant, pointing out that the two plants have similar design with respect to important parameters such as power density, steam relief, and bypass capacities that would affect the large transient performance of the plants, such that it is reason able to predict that the performance of both plants in the event of a large transient during EPU operations would be substantially the same. Entergy Dir. at A16; Entergy Exh. 38.

5 1. The NRC Staff endorsed the validity of Entergy's. comparisons between VY and Brunswick by pointing out the similarities between the two plants in critical parameters such as SRV capacity, power density and bypass valve capacity and agreeing with Entergy's inference of acceptable EPU transient behavior at VY in light of the Brunswick unplanned transient experience. Tr. 1470-74 (Abdullahi).

52. Large transient testing from EPU has been performed during the KKL (Leibstadt) power uprate implementation program, which was performed during the period from 1995 to 2000. KKL testing for major transients involved turbine trips at 113.4% OLTP and 116.7% OLTP, and a generator load rejection test at 104.2% OLTP. Entergy Dir. at A46.

53. The response of the KKL reactor and other plant equipment during those large transient tests was satisfactory. Id.

54. The fact that the Hatch, Brunswick, and Dresden plants, all of which are similar in design to VY, experienced no anomalous response to large transients from EPU operating levels supports the conclusion that VY will also respond as predicted to large transients during EPU operation. Entergy Dir. at A44. The operating experience of these plants, which have undergone such transients without adverse consequences, 36

indicates that it is not necessary to subject \\JY to such a transient. Staff Dir. at AlO; Tr.

1434-36 (Abdullahi).

55. Dr. Hopenfeld questioned reliance on the similarities between Brunswick and VY in deciding whether to waive large transient testing requirements. He testified that he would like to see a detailed uncertainty study of the differences between the two plants and mentioned the possibility that there were differences in fuel design and in the steam dryers. Tr. 1533-34 (Hopenfeld). Neither of those factors, however, is described by any other witness as having an impact on how large transients develop. Nor did Dr.

Hopenfeld testify that there were in fact differences in plant designs for Brunswick and VY that would make it inappropriate to rely upon the Brunswick experience.

56. Dr. Hopenfeld also discounted the experience at other plants that have -undergone transients from EPU conditions because each plant is different. Tr. 1550-52 (Hopenfeld). Again, he failed to point any specific difference between VY and the other plants that would warrant discounting or disregarding the transient experiences at those plants. He acknowledged, moreover, that no evidence of fuel damage had been reported at any of the plants experiencing transients from EPU and he failed to answer the Board's request that he identify any cases where the safety limits of critical power ratios had been exceeded. Tr. 155 1-53 (Hopenfeld)..

4.

Absence of New Thermal-Hydraulic Phenomena

57. The absence of new thermal -hydraulic phenomena is the second factor listed in SRP 14.2.1 that should be considered by the Staff in deciding whether to grant an exception from large transient testing from EPU operation.

58. Entergy testified that none of the modifications that have been made to implement the power uprate will introduce new thermal-hydraulic phenomena, nor are any new system interactions introduced during or as the result of analyzed transients. Entergy Dir. at 37

A55, A57. No systems were added or changed at VY that would be required to mitigate.

the consequences of the transients that would be the subject of the large transient tests.

Entergy Dir. at A55. Also, there have also been no changes in the flow or heat transfer regime in the reactor core in implementing the uprate. Tr. 1573-74 (Casillas).

59. No instances of abnormal thermal-hydraulic phenomena have been observed at any BWRs that have implemented a power uprate. Tr. 1276-79 (Casillas); Tr. 1393 (Thomas); Tr. 1393-96, 1428-29 (Jones). NEC.'s witness Dr. Hopenfeld testified that he was not aware of any such instances. Tr. 15 13-15 (Hopenfeld): He was also not aware of any calculations predicting that any abnormal thermal-hydraulic phenomena would take place in the event of a large transient. Tr. 1514-15 (Hopenfeld).

60. The operation of VY in the six months since implementation of the EPU is consistent with the industry experience of no new thermal-hydraulic phenomena. VY has exhibited no appreciable changes in thermal-hydraulic performance since implementing the uprate.

T.1274-76 (Casillas). Also, no interactions between the components of the core or other components or systems have been observed as a result of operating at EPU levels.

Tr. 1276-77 (Casillas).

5.

VY Operating Experience

61. Prior to implementation of the EPU, VY experienced a number of unplanned large transients. On March 13, 1991, with the reactor at full power, a reactor SCRAM occurred as a result of turbine/generator trip on generator load rejection due to a 345 kV Switchyard Tie Line Differential Fault. Entergy Dir. at A49. This transient was reported to the NRC in LER 1991-005-00, dated 4/12/91 (Entergy Exh. 17).

62. On April 23, 1991, with the reactor at full power, a reactor SCRAM occurred as a result of a turbine/generator trip on generator load rejection due to the receipt of a 345 kV breaker failure signal. The transient included a loss of offsite power. Entergy Dir. at 38

A49. This event was reported to the NRC in LER 199 1-009-00, dated 05/23/91 (Entergy Exh. 18).

63. on June 15, 1991, during normal operation with reactor at full power, a reactor SCRAM occurred due to a turbine control valve fast closure on generator load rejection resulting from a loss of the 345 kV North Switchyard bus. Entergy Dir. at A49. This transient was reported to the NRC in LER 1991-014-00, dated 7/15/91 (Entergy Exh. 19).

64. On June 18, 2004, during normal operation with the reactor at full power, a two phase electrical fault-to-ground caused the main generator protective relays to isolate the main generator from the grid and resulted in a generator load rejection SCRAM. Entergy Dir.

at A49. This transient was reported to the NRC in LER 2004-003-01, dated 6/18/2004 (Entergy Exh. 20).

65. On July 25, 2005, during normal operation with the reactor at full power, a generator load rejection SCRAM occurred due to an electrical transient in the 345 kV Switchyard.

--Entergy-Dir.-at A49-.-T-his-transient-was-reported--o-the NRC in LER 2005-001 -00, dated 07/22/05 (Entergy Exh. 21).

66. No significant anomalies were seen in VY's response to any of these transients. Entergy Dir. at A50.

67. The transients in 2004 and 2005 occurred after most of the modifications associated with EPU had been implemented, including the new high pressure turbine rotor, main generator stator rewind, the new high pressure feedwater heaters, condenser tube staking, an upgraded isophase bus duct cooling system, and condensate demineralizer filtered bypass. Entergy Dir. at A5 1. In each instance, the modified or added equipment functioned normally during the transient. Id.

39

68. The plant's performance during these recent transients, including that of the modified components, supports the conclusion that the plant will respond as designed to transients at EPU conditions by demonstrating that many physical modifications supporting the uprate have not adversely affected the transient response, and by validating analytical methods used to predict plant response with those modifications in place. Id. Staff Dir.

at Al 4.

6.

Similarities in Plant Configuration Pre and Post EPU

69. Entergy made over twenty modifications to VY in order to implement the EPU. Entergy Exh. 39; Tr. 1264 (Nichols). The modifications had a limited scope and did not result in the addition of any new systems that would affect the plant's response to large transients or result in new system interactions. Entergy Dir. at A57; Tr. 1265 (Nichols); Tr. 1427-29 (Jones).

70. most of the EPU modifications made at VY were made to non-safety-related components,,which are&hot &c-edited-ihnli-censiisig basis-transient analyses. Entergy Dir. at A56. incidental modifications associated with EPU, such as alarms, indications, and scaling changes, also do not impact transient response.

Id.

71. Significantly, the operating pressure was kept unchanged in the uprate, so that the performance of the plant safety systems relied upon to respond to the transients is unaffected by the uprate. Entergy Dir. at A 14; Tr. 1265-66 (Nichols).

72. Other plants implementing constant pressure uprates have made similar modifications and have not exhibited new thermal -hydraulic phenomena or different responses in the systems that were modified. Tr. 1277 (Casillas); Tr. 1394-97 (Jones, Abdullahi);

Tr. 1398-99 (Ennis).

40

7.

Analytical Predictions

73. The large transient analyses for \\1Y were performed using the ODYN computer code.

Entergy Dir. at A29. ODYN is a proprietary code developed by GE and approved by the NRC in 1981 for use in the analysis of GE BWR plant response to pressurization transients. Entergy Dir. at A30.

74. The ODYN code is the One Dimensional DYNamic (ODYN) Core Transient Model, which is designed to simulate selected fast transients of boiling water reactors. The ODYN model consists of an integrated one-dimensional reactor core model which is coupled to the recirculation and major system control models. The recirculation and control systems are integrated in the code to analyze the plant's response to fast pressurization transients. ODYN also models the steamline pressure wave response in the main steam line, which includes modeling of the main turbine control valves and bypass valves. Staff Dir. at Al 8.

75. ODYN's simulation involves describing the physical plant in the model (i.e., volumes, flow paths, resistances), establishing the desired operating conditions (i.e., water level, power, pressure) and introducing a disturbance (i.e., valve closure, pump trip, control action). The ODYN model predicts the plant response based on its physical model correlations. Entergy Dir. at A3 1.

76. The ODYN code has been benchmarked against three turbine trips conducted at the Peach Bottom Unit 2 plant. Entergy Dir. atA37. The Peach Bottom turbine trip tests used to benchmark the ODYN code represented more severe conditions than those observed in actual plant transient events, in that the reactor trip was purposefully delayed to increase the severity of the transient. Entergy Dir. atA3 1; Entergy Exh. 27, Section 3.

41

77. ODYN was also benchmarked for MSIV transients by comparing its predictions for such a transient against the results of the MSIV test conducted during startup at the Hatch plant. Entergy Dir. at A36; Tr. 1312 (Casillas).

78. As a code benchmarked against all significant transients, ODYN is capable of predicting accurately the plant behavior during transients occurring at EPU power levels. Entergy Dir. at A35.

79. ODYN has been approved by the NRC for application to the large transients of interest here (MS IV closure; generator load rejection; MSIV closure with position switch failure, i.e., MSIV flux SCRAM; turbine trip) and other plant events including loss of auxiliary power - all grid connections; feedwater controller failure - maximum demand; pressure regulator failure - closed; loss of feedwater heating; pressure regulator failure - open; recirculation flow decrease events; recirculation flow increase events; and increase in coolant inventory events. Staff Dir. at Al8; Entergy Dir. at A38.

80. The ODYN code predictions bound both the Peach Bottom test data and the results of the startup large transient tests of all other BWR plants. Tr. 1338-39 (Casillas); Entergy Dir. at A41.

81. ODYN was developed as a "best estimate" code in that it does not incorporate any deliberate conservatisms into the analytical model. Tr. 1294-95 (Casillas). However, ODYN is a one-dimensional code and includes some simplifications in going from three dimensional physical configurations to one dimension. Tr. 1294 (Casillas). These simplifications result in conservative biases in the model's predictions, which on the average overestimate the power and pressure levels experienced during the transients.

Tr. 1295 (Casillas). Thus, ODYN gives conservatively high predictions of the two main

("Level I") parameters of interest during pressurization transients (MSIV closure, generator load rejection and turbine trip), which are reactor power and pressure. Tr.

42

1306, 1327, 1605 (Casillas). ODYN also provides conservatively high predictions of several other parameters s uch as steam flow and pressure drop. Tr. 1328 (Casillas).

82. Dr. Hopenfeld raised some criticisms against the use of ODYN to predict VY's response to large transients. He pointed out that ODYN's predictions of the critical plant parameters are uniformly higher than those measured during the benchmark tests, and that the reasons for the overpredictions are not explained, so they could reflect errors in the code. Tr. 1539-41 (Nopenfeld).

83., A number of factors may account for the discrepancies between the ODYN code predictions and the plant test data. First, the condensing efficiency, of the heated water that condenses some of the steam is not modeled in ODYN, leading to a higher prediction of peak pressure than occurs in reality. Tr. 1307-08 (Casillas). There is also the use by ODYN of average properties of the reactor, which tends to introduce a "6smearing" effect in the results. Tr. 1309-10 (Casillas).

84. The ODYN model has been upgraded since its introduction to include greater modeling detail such as increased nodes, advanced physics correlations, and more representative control systems. Entergy Reb. at A12. These changes have consistently improved the accuracy of the ODYN code and reduced the uncertainty in its predictions compared against the qualification tests. Id. Tr. 1314 (Casillas).

85. Every time a new version of ODYN is introduced, GE re-performs, the qualification of the code against the Peach Bottom test data. Entergy Dir. at A37; Tr. 1312-13 (Casillas);

Staff Dir. at A22. The current version of ODYN cuts the difference between analytical prediction and qualification test results in about half from the differences obtained with the code version used at the time ODYN was first benchmarked against Peach Bottom test data. Tr. 1300 (Casillas).

43

86. In every instance in which unplanned large transients from EPU power levels have been experienced at these plants and an analysis of the scenario involved in the transients existed, the plant's response was bounded by the analyses performed using ODYN.

En~tergy Dir. at A45. Since ODYN has provided adequate analytical predictions of transient performance for a variety of plants undergoing EPU, such as Hatch, it can provide similar predictions for VY. Tr. 1434 (Abdullahi).

87. A comparison of the KKL turbine test transient performance against the ODYN predictions shows consistency between the test results and those predicted in the model's qualification, as well as in other comparisons between ODYN runs and plant operating data. in all cases, the ODYN model slightly overpredicts vessel peak pressure. Entergy Dir. at A47.

88. The KKL turbine trip test is an excellent prediction of what a test at VY would show because K-KL has a 2% higher power density than VY and both plants have a full turbine

__bypass capacity design. Id.

89. Another criticism raised by Dr. Hopenfeld against ODYN was that certain parameters in the thermal-hydraulic model (the drift velocity vgj and the void distribution c,,) are inappropriate because they were determined experimentally under steady state conditions that do not apply to transients. Entergy Exh. 23, Table 1; Tr. 1545-46 (Hopenfeld).

90. The Staff evaluated the adequacy of the ODYN one-dimensional thermal-hydraulic model against the measured parameters during the Peach Bottom tests (Local Power Range Monitor flux reading and power distribution) at a given axial location. The change in critical power ratio ("ACPR") values predicted by ODYN for a given test were compared against the ACPR obtained in the tests by using the measured core parameters.

The Staff found that the code demonstrates good prediction against existing the Peach*

44

Bottom test data, and that the ACPR calculation from the ODYN code is neither conservative nor non-conservative, but that it predicts the available data well and within the expected uncertainty'range. Further, based on the Peach Bottom tests, the Staff determined that ODYN is a "best estimate" code for ACPR calculations. Staff Dir. at A22.

91. It is not necessary to resolve the disagreement between Dr. Hopenfeld and the Staff about the adequacy of ODYN's thermal-hydraulic model because the ODYN analyses tend to overestimate the reactor pressures and power levels, thus the errors if they exist do not result in nonconservative predictions of plant behavior. In addition, even if Dr.

Hopenfeld's criticisms of the ODYN code are accepted, their impact on the determination of whether an exception to large transient testing is appropriate would be minimal, because the most important factor in making such a decision is not the accuracy of ODYN, but rather the operating experience of VY and other facilities. Tr. at 1435 (Abdullahi).________

92. Entergy and other licensees are required to perform transient analyses, including pressurization transients, for every reload. Tr. 1388-89 (Abdullahi); Tr. 1583 (Casillas).

in compliance with this requirement, VY has analyzed the limiting transients for each fuel cycle using ODYN. Entergy Dir. atA54. Those analyses utilize plant-specific core neutronic and thermal-hydraulic conditions as inputs. Staff Dir. at A 19.

93. in advance of implementation of the EPU, GE prepared in December 2005 an updated Supplemental Reload Licensing Report ("SRLR") containing analyses of the predicted performance of VY under EPU conditions. (Entergy Exhs. 8, 28). The SRLR contained, among others analyses, the results of licensing basis generator load rejection and MSIV closure simulations conducted using the ODYN code. Id. The results of these simulations verified that: (1) these transients remain the limiting transients from the 45

perspective of the selected parameters, and (2) the results remain well within the design and license limits. Entergy Dir. at A40.

94. In addition, several VY plant transients have been compared against ODYN predictions over the years to assess the specific BWR licensing basis. All of these comparisons have determined that the licensing predictions are bounding and that the plant equipment response is consistent with its design basis. Entergy Dir. at A41.

8.

System and Component Testing

95. Pursuant to 10 C.F.R. § 50.36, a reactor's Technical Specifications are required to include items in the following five specific categories: (1) safety limits, limiting safety system settings, and limiting control settings; (2) limiting conditions for operation

("LCOs"); (3) surveillance requirements; (4) design features; and (5) administrative controls. Staff Dir. at Al 5. When an LCO is met, the associated structures, systems and components ("SSCs") are considered to be operable. Id.

96. Technical Specification-required surveillance testing (emg., component testing, trip logic system testing, simulated actuation testing) is routinely performed at VY during plant operations. Such testing demonstrates that the SSCs required for appropriate transient performance will perform their functions, including integrated performance for transient mitigation as assumed in the transient analysis. Entergy Dir. at A52; Staff Dir. at Al15.

Dr. Hopenfeld testified that he would not recommend performing the large transient tests in order to verify component functionality because he had confidence that Entergy had verified through testing that each of the components required to respond to the transients would operate as required. Tr. 1528-29 (Hopenfeld).

97. At VY, the MSIVs are tested, quarterly. The safety relief valves and spring safety valves are tested once every operating cycle. These valves are required to perform in accordance with the design during large transients; their periodic testing assures that 46

their performance during large transients will be acceptable. The reactor protection system instrumentation that is relied on to mitigate large transients is tested quarterly, assuring it will carry out its safety function in the event of a large transient. Entergy Dir.

at A5 3; Staff Dir. at A 15.

98. Because the characteristics and functions of SSCs are tested periodically during plant operations, they do not need to be demonstrated further in a large transient test.

Therefore, periodic testing of SSCs during steady-state plant operation can confirm performance characteristics of SSCs required for appropriate transient response. Staff Dir. at A15; Tr. 1429-30 (Jones, Abdullahi).

9.

Conformance with Guidance Contained in Vendor Topical Reports

99. The VY EPU Application was prepared following the guidelines contained in the CPPU Topical Report. Entergy Dir. at A13; NRC Staff Dir. at AlO; EPU SER at 271.

10.

Potential Effects of Large Transient on Steam Dryer 100. NEC witness Dr. Hopenfeld expressed a concern that the structural integrity of the steam dryer could be affected by the EPU because the greater flow velocity at EPU conditions increases turbulence at vortex shedding frequencies and thereby increases loads on the dryer. NEC Dir. at Al 0. At the hearing, Dr. Hopenfeld testifi ed that his concern about the impact on the steam dryer of a large transient would be that if the dryer was already weakened through repeated fatigue cycles or was suffering from stress corrosion cracking, resonant vibrations produced by the transient "would cause potential problemlis]." Tr. 15 16-20 (Hopenfeld).

101. Dr. Hopenfeld did not indicate that the \\JY steam dryer is weakened or cracked, and did not know whether resonant vibrations that could lead to damage to the dryer would result from a large transient at VY. Tr. 1517 (Hopenfeld). He generally referred to 47

"observations in power plants where during an event...

the plant had experienced very.

severe vibrations." Tr. 1521 (Hopenfeld). He did not identify what plants he was referring to and indicated that such a phenomenon "has nothing to do with BWVRs even," id, bringing into serious question the relevance of his concerns to VY.

102. Flow induced vibration loads on the steam dryer are steady-state long term effects. Tr.

1287-88 (Nichols). The Staff guidance on EPU testing calls for the conducting of vibration testing and monitoring of reactor vessel internals. Such testing is to be conducted under steady state conditions, not through transient testing. Tr. 1478-1480, 1485 (Ennis).

103. Determnination of dynamic loadings on components is not the purpose of either the large transient analyses performed by ODYN or the large transient tests themselves. The purposes of both the analyses and the large transient tests are to determine (1) the peak pressure transient in the case of the MSIV closure, or (2) the greatest transient challenge to the reactor thermal limits in the case of the generator load rejection. Dynamic loadings of components under normal, upset, or faulted conditions (including transients) are covered in separate analyses and acceptance criteria. Entergy Reb. at A24.

104. Large transient testing provides information on the peak reactor vessel pressure and power level (i.e., temperature increase) resulting from the pressurization caused by the large transients, but provides no information for use in deriving either fatigue factors on the steam dryer or the loadings to which the dryer will be subjected. Entergy Reb. at A25.

105. The Safety Evaluation Report for the CPPU Topical Report discusses an acceptable methodology for evaluating the stresses on various components subject to increased loadings due to poweruprate conditions for plants using the CPPU approach (such as VY). Specifically, Section 3.2 of the CPPU SER discusses the reactor pressure vessel 48

and its internals, and Section 3.4 discusses piping systems and the associated components (2g nozzles, anchors., pumps, valves, supports). As described in those sections of the CPPU SE, the loads and load combinations are evaluated for normal operation, upset (i.e., transient), emergency, and faulted conditions to determine if the calculated stresses and fatigue usage factors are less than the code allowable limits.

Staff Dir. at A 16; Entergy Exhs. 2 5 and 30OP at § § 3.2, 3.4.

106. For Vermont Yankee, specific details regarding how stresses were analyzed for the steam dryer are discussed in Section 2.2.6.1 of the SER. Id. Staff Exh. 1 and 2 at § 2.2.6.1 (pp. 41-51).

107. The analyses of the stresses on the steam dryer under EPU operating conditions were conducted using methodologies described by GE in the CPPU Topical Report and the stresses were confirmed to be acceptable under all conditions, including transients. Tr.

1483-86 (Ennis).

108. The loadings imparted on the steam dryer by the large transients of interest are of short duration and are well within design margins. Tr. 1289 (Nichols).

109. The pressure wave traveling through the steam lines would impinge on the dryer's front face, which at VY has been strengthened to a one inch thickness. Id. This dryer modification preceded the uprate implementation by two years and was prompted by GE recommendations on how to strengthen the dryer against steady state loadings. Tr.

1575-76 (Nichols).

1 10. For those reasons, performing large transient testing would provide no meaningful information on the loads on the dryer. Tr. 1289-90 (Casillas).

49

11.

Plant Impacts and Costs due to Large Transient Testing 111. There are minimal, if any, safety risks or concerns involved in the performance of large transient tests. Tr. 1236 (Nichols, Casillas).

112. No additional plant instrumentation would need to be installed to conduct the large transient tests. Tr. 1203 (Nichols); Tr. 1205-06, Tr. 1212-15 (Casillas); Tr. 1415 (Abdullahi); Tr. 1524-25 (Hopenfeld).

113. Performance of large transient tests would impose additional thermal cycles on the plant's primary system. Entergy Dir. at A58; Tr. 1230 (Casillas). Some plant components that are not intended to be ever replaced, such as the reactor vessel, the nozzles and the core plate structures, have only a limited number of allowed thermal cycles. Tr. 1234-35 (Casillas). VY has a design limit of 270 thermal cycles, of which between 70 and 100 have been experienced to date. Tr. 1291-92 (Casillas).

114. Performance of large transient tests would require developing test procedures and assembling an organization to conduct the tests and check the plant condition before and after the tests. Tr. 1201-03 (Nichols); Tr. 1204-05 (Casillas). There would be internal labor costs associated with planning and performing the tests, which would involve twenty to thirty plant staff people. Tr. 1244-45 (Nichols). Writing a test procedure would cost on the order of $25,000. Tr. 1245-46 (Nichols).

115. There would be significant plant availability penalties associated with performing the large transient tests. The plant would have to be offline for a minimum of two days for every test that was conducted. Entergy Dir. at A58; Tr. 1247 (Nichols). A two day outage would result in a loss of revenue to Entergy on the order of one and a half million dollars. Tr. 1248 (Nichols). Complications such as equipment breakdowns could result in extending the outage by several days. Tr. 1247-48 (Nichols).

50

D.

Summary of Findings 116. The evidence presented by the parties on NEC Contention 3 demonstrates that large transient testing from full power EPU levels can be performed safely but carrying out those tests will have adverse availability and economic consequences and will lead to an outage of the facility for at least several days.

117. Large transient testing, if performed at VY, will not provide any additional information about the plant's response to a large transient that is not already available from the component and system testing that is routinely performed at VY, VY's pre-EPU transient performance, and the operating experience of other similar BWVRs that have undergone unanticipated large transients from EPU levels. These sources, plus the analytical predictions performed using the ODYN code, provide a high degree of confidence that the VY facility will perform satisfactorily and will shut down safely in the event of a large transient (MSIV closure, generator load rejection, or turbine trip) from full EPU power levels.

118. The concerns expressed by NEC in Contention 3 - which largely relate to the impact of a large transient on components such as the steam dryer - are not addressed by performing large transient testing because large transients do not impart bounding loads on the steam dryer and provide no information for use in deriving either fatigue factors on the steam dryer or the loadings to which the dryer will be subjected during long term plant operations.

119. Performance of l arge transient testing is not justified on the basis of NEC's concerns, which are found to be lacking in merit.

120. The record shows that the large transient tests addressed in NEC Contention 3 are not required to demonstrate that structures, systems and components important to safety will perform satisfactorily in service at VY under EPU conditions. Accordingly, the 51

exception from such tests requested by Entergy is warranted and was appropriately granted by the Staff.

IV.

CONCLUSIONS OF LAW The Licensing Board has considered all of the material presented by the parties on NEC Contention 3. Based upon a review of the entire evidentiary record in this proceeding and the proposed findings of fact and conclusions of law submitted by the parties, and in accordance with the findings of fact set forth above, which are supported by a preponderance of the reliable, material and probative evidence in the record, the Board has decided the matters in controversy concerning this contention and reaches the following legal conclusions.

2.

The acceptance criteria for the VY EPU test program "are based on 10 CFR Part 50, Appendix B, Criterion X1, which requires establishment of a test program to demonstrate that SSCs will perform satisfactorily in service." SER at260.

3.

The legal standard for determining whether the EPU should be approved without the performance of large transient testing is whether, in the. absence of such testing, the test program implemented by Entergy for the EPU complies with Criterion XI by demonstrating that structures, systems, and components will perform satisfactorily in service at the proposed EPU power level.

4.

The evidence submitted in this proceeding demonstrates that that VY's structures, systems, and components will perform satisfactorily in service at the proposed EPU power level. This demonstration has been achieved without the need to perform large transient testing.

52

5.

Entergy has provided reasonable assurance that the grant of its request for an exception from the performance of large transient testing will not endanger life or property or the common defense and security and is otherwise in the public interest.

6.

The amendment to Facility Operating License No. DPR-28 for operation of the Vermont Yankee Nuclear Power Station, to increase the maximum authorized power level of the facility from 1593 megawatts thermal (MWt) to 1912 MWt should be granted.

Respectfully submitted,

</)A4 A'244Yf Jay E. Silberg 5

Matias F. Travieso-Diaz Scott A. Vance PILLSBURY WINTHROP SHAW PITTMAN LLP 2300 N Street, N.W.

Washington, DC 20037-1128 Counsel for Entergy Nuclear Vermont Yankee, LLC and Entergy Nuclear Operations, Inc.

November 7, 2006 53

UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION Before the Atomic Safety and Licensing-Board In the Matter of ENTERGY NUCLEAR VERMONT YANKEE, LLC and ENTERGY NUCLEAR OPERATIONS, INC.

(Vermont Yankee Nuclear Power Station)

) Docket No. 50-27 1

)

)

)

)

)

ASLBP No. 04-832-02-OLA (Operating License Amendment)

CERTIFICATE OF SERVICE I hereby certify that copies of "Entergy's Proposed Findings of Fact and Conclusions of Law on New England Coalition's Contention 3" were served on the persons listed below by deposit in the U.S. mail, first class, postage prepaid, and where indicated by an asterisk by electronic mail, this 7th day. of November, 2006.

.*Administrative Judge Alex S. Karlin, Chair Atomic Safety and Licensing Board Panel Mail Stop T-3 F23 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 ask2a~nrc. gov

• Administrative Judge Dr. Anthony J. Baratta Atomic Safety and Licensing Board Panel Mail Stop T-3 F23 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 ajb5a~nrc. gov

• Administrative Judge Lester S. Rubenstein 4760 East Country Villa Drive Tucson, AZ 85718 lesrrr(acomcast.net Atomic Safety and Licensing Board Mail Stop T-3 F23 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001

• Secretar~y Att'n: Rulemakings and Adjudications Staff Mail Stop 0-16 ClI U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 secv(a~nrc.go, hearingdocket2Iwnc.gov

• Raymond Shadis New England Coalition P.O. Box 98 Shadis Road Edgecomb, ME 04556 shadis(ad)prexar.com

• Marcia Carpentier, Esq.

Atomic Safety and Licensing Board Panel Mail Stop T-3 F23 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-000 1 MXC7(?iRnrc. gov Office of Commission Appellate Adjudication Mail Stop 0-16 C I U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001

• SewnE. Turk, Esq.

• Steven C. Hamrick, Esq.

Office of the General Counsel Mail Stop 0- 15 D21 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 set(anrc.go, schl(o&nrc.gov

• Jonathan M. Rund, Esq..

Atomic Safety and Licensing Board Panel Mail Stop T-3 F23 U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 imr3(a-nrc. gov

~&~iv.~

C Matias F. Travie am-

"41 2