ML080250162

Response to NRC Request for Additional Information Regarding Nine Mile Point Nuclear Station, Unit No. 1, Revision of Rod Worth Minimizer Limiting Condition for Operation During Startup

ML080250162
Person / Time
Site:	Nine Mile Point
Issue date:	01/24/2008
From:	Belcher S Constellation Energy Group
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
TAC MD6215
Download: ML080250162 (10)

Text

Sam L. Belcher P.O. Box 63 Plant General Manager Lycoming, New York 13093 315.349.5200 315.349.1321 Fax 0(\ Constellation Energy"

";"

• Nine Mile Point Nuclear Station January 24, 2008

u. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

SUBJECT:

Nine Mile Point Nuclear Station Unit No.1; Docket No . 50-220 Response to NRC Request for Additional Information Regarding Nine Mile Point Nuclear Station, Unit No.1 , Revision of Rod Worth Minimizer Limiting Condition for Operation During Startup ITAC No. MD6215)

REFERENCES:

(a) Letter from K. J. Polson (NMPNS) to Document Control Desk (NRC), dated July 23, 2007 , License Amendment Request Pursuant to 10 CFR 50.90: Revision of Rod Worth Minimizer Limiting Condition for Operation During Startup -

Technical Specification Section 3.1.1.b (b) Letter from M. J. David (NRC) to K. J. Polson (NMPNS), dated November 27, 2007 , Request for Additional Information Regarding Nine Mile Point Nuclear Station, Unit No.1, Revision of Rod Worth Minimizer Limiting Condition for Operation During Startup (TAC No. MD6215)

Pursuant to 10 CFR 50.90, Nine Mile Point Nuclear Station, LLC (NMPNS), requested, in Reference (a),

approval of an amendment to the Nine Mile Point Unit 1 Renewed Operating License DPR-63 to revise Technical Specifications (TS) 3.1.1, "Control Rod System" to incorporate a provision that should the Rod Worth Minimizer (RWM) become inoperable before a reactor startup is commenced or before the first 12 rods have been withdrawn, startup would be allowed to continue. This provision would rely on the RWM function being performed manually and would require a check of compliance with the rod control program by a second licensed operator or other qualified member of the technical staff. The use of this allowance would be limited to one startup in the last calendar year. The purpose of this letter is to provide responses to the request for additional information (RAI) transmitted to NMPNS in Reference (b).

Docwnent Control Desk January 24, 2008 Page 2 Response to the RAJ is provided in Attachment (1). Revisions to the proposed TS Bases, provided for information only, are shown in Attachments (2). This response does not affect the No Significant Hazards Determination analysis provided by NMPNS in Reference (a). Pursuant to 10 CFR 50.91(b)(1),

NMPNS has provided a copy of this response, with attachments, to the appropriate state representative.

This letter contains no regulatory commitments. Should you have any questions regarding the information in this submittal, please contact T. F. Syrell, Licensing Director, at (315) 349-5219.

Very truly yours, STATE OF NEW YORK TO WIT:

COUNTY OF OSWEGO I, Sam L. Belcher, being duly sworn, state that I am Plant General Manager, and that I am duly authorized to execute and file this request on behalf of Nine Mile Point Nuclear Station, LLC. To the best of my knowledge and belief, the statements contained in this docwnent are true and correct. To the extent that these statements are not based on my personal knowledge, they are based upon information provided by other Nine Mile Point employees and/or consultants. Such information has been reviewed in accordance with company practice and I believe it to be reliable.

Subscribed and sworn before me, a Notary Public in and for the State of New York and County of 65~o , this a day of...Ja n U;>1Jr , 2008.

WITNESS my Hand and Notarial Seal: ~~ rNOtaf)lblic ~

TONYALJONES l

, DAte NotaIy P,ubli.c in the State of New York Oewego~ R~. No. 01~

NV CommIation Expiretl Jf@j,aOI{) .

SLB/GB

Document Control Desk January 24, 2008 Page 3 Attachments: (1) NMPNS Response to NRC Request for Additional Information Regarding Revision of Rod Worth Minimizer Limiting Condition for Operation During Startup (2) Proposed Technical Specification Bases Changes (Marked Up Page) cc: S. J. Collins, NRC Regional Administrator, Region I M. J. David, NRC Project Manager Senior NRC Resident Inspector J. P. Spath, NYSERDA

ATTACHMENT (!}

NMPNS RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING REVISION OF ROD WORTH MINIMIZER LIMITING CONDITION FOR OPERATION DURING STARTUP Nine Mile Point Nuclear Station, LLC January 24, 2008

ATTACHMENT (1)

NMPNS RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING REVISION OF ROD WORTH MINIMIZER LIMITING CONDITION FOR OPERATION DURING STARTUP This attachment provides Nine Mile Point Nuclear Station, LLC (NMPNS) responses to the request for additional information documented in the NRC letter dated November 27,2007. Each NRC question is restated (in italics), followed by the NMPNS response.

Question 1 The key difference between the current TS 3.1.1.b operability requirement for the RWM during startup, and the proposed TS revision that will allow an individual to perform the function of RWM manually during startup once, in a calendar year (i.e., ifnot performed in the last 12 months), is that the proposed change will introduce human supervision in place ofautomatic supervision. The NRC staffbelieves that manual operation of control rods (CRs) during startup could result in withdrawal ofan incorrect CR of high worth due to human error, followed by a Control Rod Drop Accident (CRDA). Therefore, state whether the introduction of the human performance factor was considered while performing the safety analysis of the proposed modification, as part of the NRC staff-approved generic General Electric Standard Application for Reactor Fuel methodology in NEDE-24011-P-A, or on a plant-specific basis. If so, explain how introduction of human performance will not significantly increase the probability of the CRDA previously evaluated.

If the human performance factor was not considered in the safety analysis of the proposed change, then explain why not.

NMPNS Response The inclusion of the human performance factor, specifically, the use of human supervision (manually fulfilling the control rod pattern conformance function during startup) in place of the automatic supervision, was taken into account while performing the safety evaluation in support of the proposed Technical Specifications (TS) amendment. A summary of those considerations follows.

It should be noted that Nine Mile Point Unit No. I (NMPI) TS Section 3.3.1, Limiting Condition for Operation (LCO) 3.1.1.b(3)(b) presently contains a substitution clause allowing for the use of a second independent operator or engineer during a reactor startup in the event the Rod Worth Minimizer (RWM) becomes inoperable. There also exists historical NRC supporting data (NRC Safety Evaluation, Reference I) which further provides demonstration that the introduction of the human supervision factor was previously evaluated and approved.

In 1986, the Boiling Water Reactor Owners' Group (BWROG) proposed to the NRC (Reference 2), a revision to the General Electric Licensing Topical Report NEDE-24011-P-A accompanied by the BWROG report, "Modifications to the Requirements for Control Rod Drop Accident Mitigating Systems." The submittal included detailed probabilistic analyses of the rod drop accident events including the use of either the RWM or manually fulfilling the control rod pattern conformance function during rod withdrawal. The report concluded that when using either method, there remained a very low probability (10. 12) of a CRDA occurring which would result in a peak fuel enthalpy of greater than the 280 callgm design limit. The NRC resultant safety evaluation (Reference I) accepted the report for referencing in license applications.

The probabilistic evaluation contained in Reference 2, and accepted in Reference I, combined the probability of all of the multiple events necessary to occur for a CRDA. Included in the evaluation for the lof3

ATTACHMENT (1)

NMPNS RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING REVISION OF ROD WORTH MINIMIZER LIMITING CONDITION FOR OPERATION DURING STARTUP CRDA event scenario was the fact that the maximum control rod worth was considered for both the RWM (mechanical) malfunction and an inadvertent operator error. The use of either variable resulted in the same low probability value (10- 12), and supported the conclusion that considerable conservatism remains for the potential of occurrence of a CRDA event when using either the mechanical or human supervision RWM function. Therefore, it was concluded that the introduction of human performance element would not significantly increase the probability of the CRDA previously evaluated.

Ouestion 2 It was stated in proposed Insert 1 for TS 3.1.1.b(3)(b)(ii) that, "....provided that a second licensed operator or other qualified member ofthe technical staffverifies that the licensed operator at the reactor console is following the control rod program." Describe the specific qualification requirements, the training program, and the title of the member of the technical staff who will be authorized to perform independent verification ofCR movement during the startup when the RWM becomes inoperable.

NMPNS Response NMPNS Administrative Procedure, CNG-OP-3.01-1000, "Reactivity Management" defines the philosophy, responsibilities, and requirements necessary to implement Reactivity Management. Control rod movement activity requirements, detailed within the procedure, define the independent verifier as the "Additional Qualified Individual" of which a Senior Reactor Operator (SRO), a Reactor Operator, a Shift Technical Advisor (STA), or a Reactor Engineer can be assigned. The last two referenced independent verifier positions are those that are considered to be a member of the NMPI "technical staff."

Initial qualification requirements for the position of STA include: (1) Having at least one year of operation or engineering support of a nuclear power plant, six months of which has been at the NMPNS; (2) hold a bachelor's degree in Engineering or Physical Science, or sufficient courses to provide a background for understanding the plant; (3) hold either a current SRO license, hold a current SRO Certification, be a SRO Certified Instructor, or be an SRO Certified Engineer; and (4) completion of the STA On-The-Job Training Manual. The continuing training program for the position of STA is participation in Licensed Operator Requalification Training with written examinations and simulator evaluations to determine STA position proficiency.

Qualification requirements for Reactor Engineer include: (1) the person must meet or exceed American National Standards Institute ANSI NI8 .1-1971, "Selection and Training of Nuclear Power Plant Personnel" qualification requirements for the position of Reactor Engineering; and (2) must complete all training qualification requirements for reactor engineer within the NMPNS training qualification matrix including the Station Nuclear Engineering Certification.

The proposed Bases for TS 3.1.1 and 4.1.1 have been further revised (See Attachment 2) to provide clarification with respect to the NMPI positions that meet the requirements necessary to fulfill the duties of a "qualified member of the technical staff." Revisions are shown with * *~. The TS Bases changes are provided for information only and will be processed in accordance with the NMPI TS Bases Control Program (TS 6.5.6).

20f3

ATTACHMENT (1)

NMPNS RESPONSE TO NRC REQUEST FOR ADDITIONAL INFORMATION REGARDING REVISION OF ROD WORTH MINIMIZER LIMITING CONDITION FOR OPERATION DURING STARTUP Question 3 It was stated in proposed Insert 1 for TS 3.1.1.b(3)(b)(iii) that, "Should the rod worth minimizer become inoperable before a startup is commenced or before the first 12 control rods have been withdrawn, the startup may continue provided that a startup with the rod worth minimizer inoperable has not been performed in the last calendar year, ... ", Please describe the process for determining and for assuring that a startup with the RWM inoperable has not been performed in the last calendar year. If the RWM is declared inoperable, what is the process for determining the reason for the failure of the RWM and subsequent corrective actions. Describe what NRC reporting requirements will be implemented. For example, some licensees have committed to notify NRC in a special report, within 30 days ofthe startup, stating the reason for the failure of the RWM, the actions taken to repair it, and the schedule for completion ofthe repairs.

NMPNS Response The current Nine Mile Point Unit 2 (NMP2) TS and TS Bases contain similar LCO allowances as those proposed for NMPI when the RWM becomes inoperable. The RWM operating procedure for NMP2 provides operator guidance when the RWM is bypassed (inoperable) during plant startup . Operators are directed to verify, by administrative methods, that startup with the RWM inoperable, has not been performed in the last 12 months. The current verification practice is to review the previous twelve months operator logs. This same practice will be available to control room operators at NMPI.

The NMPNS Corrective Action Program is the primary day-to-day method for site identification of issues/concerns and determination of resolution effectiveness. The Program provides prompt identification, documentation, evaluation and correction of conditions consistent with industry best practices.

NUREG-1433 , "Standard Technical Specifications General Electric Plants, BWR/4 Specifications,"

Revision 3.1, provides the most current NRC template for TS requirements. The NUREG does not contain reporting requirements for an inoperable RWM. Consistent with the NUREG, NMPNS is not proposing any Special Reports associated with an inoperable RWM. Items entered into the Corrective Action Program are available for NRC review.

References

1. Letter from A. C. Thadani, Assistant Director for Systems, Division of Engineering & Systems Technology (NRC) to J. S. Charnley, Manager Fuel Licensing, Nuclear Safety & Licensing (General Electric Company) dated December 27, 1987, Acceptance for Referencing of Licensing Topical Report NEDE-24011-P-A, "General Electric Standard Application for Reactor Fuel,"

Revision 8, Amendment 17.

2. Letter from T. A. Pickens, Chairman BWR Owners' Group to G. C. Lainas, Assistant Director, Division ofBWR Licensing (NRC), dated August 15, 1986, "Amendment 17 to General Electric Licensing Topical Report NEDE-24011-P-A.

30f3

ATTACHMENT @

PROPOSED TECHNICAL SPECIFICATION BASES CHANGES (MARKED UP PAGE)

TS Bases Page 41 Nine Mile Point Nuclear Station, LLC January 24,2008

BASES FOR 3.1.1 AND 4.1.1 CONTROL ROD SYSTEM

rn S<.-r-r- A.. ...,

f (4) The source range monitor (SRM) system performs no automatic safety function . It does provide the operator with a visual indication of neutron level which is needed for knowledgeable and efficient reactor startup at low neutron levels. The results of reactivity accidents are functions of the initial neutron flux .

The requirement of at least 3 cps assures that any transient begins at or above the initial value of 10-8 of rated power used in the analyses of transients from cold conditions. One operable SRM channel would be adequate to monitor the approach to critical using homogeneous patterns of scattered control rods . A minimum of three operable SRMs is required as an added conservation.

c. Scram Insertion Times The revised scram insertion times have been established as the limiting condition for operation since the postulated rod drop analysis and associated maximum in-sequence control rod worth are based on the revised scram insertion times . The specified times are based on design requirements for control rod scram at reactor pressures above 950 psig. For reactor pressures above 800 psig and below 950 psig the measured scram times may be longer. The analysis discussed in the next paragraph is still valid since the use of the revised scram insertion times would result in greater margins to safety valves lifting .

AMeNDME~JT ~JO. 142 Revision .. ~A,17i~ 41

INSERT A (For Bases for Sections 3.1 .1 and 4.1.1, TS Page 41)

The RWM provides automatic supervision to assure that out-of-sequence control rods will not be withdrawn or inserted during startup or shutdown, such that only specified control rod sequences and relative positions are allowed over the operating range from all rods inserted to 10% RTP. It serves as an independent backup of the normal withdrawal procedure followed by the operator. With the RWM inoperable during a reactor startup, the operator is still capable of enforcing the prescribed control rod sequence, however, the overall reliability is reduced because a single operator error can result in violating the control rod sequence.

If the RWM becomes inoperable after at least 12 control rods have been withdrawn, startup may continue if the RWM function is eerformed m ~nually and a required l~fl~mff{l~@it]~:!:!Jm2~ by a second licensed,~_\t 1t~Cf9:r£~j(el\aitil1) or §Viii qualified member of the technical staff (_.iff!fI~~lrllI_:tmE1lU91fLQ.I) is performed.

Also, if.the RWM is inoperable prior to com~enc~me.n..t .o.fS. tartu p,. ~r b.~comes inopera..b..le during a startu~, prior. to. ?O~

.r.n. , Ie.t e withq~:r.a.w.. a.1 of the first 12 control rods, startup may continue If th~ ~WM functl~n ISEerformed man~,ally ~nd a required a~1!ImID~D

. . ,b.x a.sesond lice.nsed operator. ( '. ." .. , .,, ;~r~~~!i1lll=a~'i1QD) or . qualified member of the technical staff (mg!a!lf~ff.~I~g~(s0jJ;::" ~L~. "'

• rte ~1d~§) is performed, and provided that a startup with the RWM inoperable was not performed in the last 12 months. In both cases, procedural control is exercised by verifying all control rod positions after the withdrawal of each group, prior to proceeding to the next group. Allowing substitution of a second licensed operator or other qualified member of the technical staff in case of RWM inoperability recognizes the capability to adequately monitor proper rod sequencing in an alternate manner without unduly restricting plant operations. Above 10% power, there is no requirement that the RWM be operable since the control rod drop accident with out-of-sequence rods will result in a peak fuel energy content of less than 280 cal/gm. The allowed frequency requirements of performing a reactor startup with the RWM inoperable (Le., if not performed in the last 12 months) minimizes the number of reactor startups performed with the RWM inoperable