3F1197-29, Responds to NRC Expressing Concerns Re Basis for & Conclusion of USQ Determination for Resolution of Jet Impingement Issue Provided on 970929.10CFR50.59 Program for CR-3 Sound & Effective

Responds to NRC Expressing Concerns Re Basis for & Conclusion of USQ Determination for Resolution of Jet Impingement Issue Provided on 970929.10CFR50.59 Program for CR-3 Sound & Effective

ML20198R675
Person / Time
Site:	Crystal River
Issue date:	11/07/1997
From:	Holden J FLORIDA POWER CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
3F1197-29, TAC-M96604, NUDOCS 9711130352
Download: ML20198R675 (5)

Text

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.m' November 7,1997 3F1197 29 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001

Subject:

Response to NRC Request for Additional Information Regarding Protection Againtt Dynamic Effects of LOCA (TAC No. M96604)

References:

1.

NRC to FPC letter, 3N10974)9, dated October 9,1997 2.

FPC to NRC letter, 3F0937-01, dated September 29,1997, " Protection Against Dynamic Effects of LOCA" 3.

FPC to NRC letter, 3F0997-28, dated September 12,1997, " Post LOCA Boron Precipitation Mitigation Plan" 4.

FPC to NRC letter, 3F1097-32, dated October 31,1997, " License Amendme Request #223, Post - LOCA Boron Precipitation Prevention" fDOI I

Dear Sir:

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Florida Power Corporation (FPC) is submitting this letter in response to a Nuclear Regulatory Commission (NRC) letter dated October 9,1997 (Reference 1).

In that letter, the NRC g:g!*

cxpressed concerns regarding the basis for and conclusion of the Unreviewed Safety Question E*

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(USQ) detennination for resolution of the jet impingement issue provided to the NRC on gjig September 29,1997 (Reference 2). In addition to that specific issue, the NRC indicated its M.

concern with recent FPC performance in the aiea of 10 CFR 50.59 implementation.

In

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particular, the NRC concluded that creditirig the reactor coolant hot leg nozzle gap (Reference

3) as a method for preventing boron precipitation based on an NRC letter to the Babcock and Wilcox Owners Group (B&WOG) demonstrated a lack of understanding and implementation of the requirements for 10 CFR 50.59. In this light, the NRC requested that FPC determine the extent of condition of this type of deficiency and provide the NRC with any corrective actioas anticipated to improve, performance in this area. On October 22,1997, FPC met with the NRC

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APage 2 of 43 s

1 staff to ' discuss the'above issues. During the meeting, FPC acknowledged a lack of clarity in

. presenting the issues to the NRC in References 1 and 3. - FPC also indicated that as a result of significant improvement in the CR-310 CFR 50.59 program, we concluded that these oversights either were isolated occurrences or occurred prior to the 10 CFR 50.59 program enhancements._.

l The following provides the results of our assessments and actions that address each of the issues discussed in your letter..

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JO CFR '50.59 Program 1

The current 10= CFR 50.59 program for Crystal River Unit 3 (CR-3) is effective.

The

. improvements made to the program over the past year have produced a quality 10 CFR 50.59 process. The improvements included a new 10 CFR 50.59 process, formal 50.59 training, and creation of a safety analysis review group. Program enhancements have been validated by FPC Quality Program Depanment assessments and confirmed through an NRC inspection. FPC acknowledges that better consistency in 50.59 program implementation needed to be achieved..

A_ccordmgly, a Corrective Action document (Precursor Card 97-7038) was initiated to formalize the pctential concern and the actions to be taken to determine whether your noted deficiencies are indicative of programmatic issues. As discussed later in this letter, the appropriate actions

~ for these two issues are being taken.

'A review-was condocted by FPC of the jet impingement and boron precipitation mitigation submittals and the supporting documentation (i.e., Safety Assessments /USQDs, vendor reports, inspection reports, etc.). :During the week of October 13, 1997, FPC had an independent third

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party conduct a review of significant 10 CFR 50.59 evaluations performed by FPC that were dispositioned as not being an USQ.- Participants in the third pa.ty review had extensive industry experience in assessing the adequacy of regulatory compliance matters. The findings of the third pany_ review condrmed, in general, that conclusions reached by FPC on the 10 CFR 50.59 evaluations arrived at a correct result. The exception noted was for the conclusion of the jet impingement issue. The third party assessment concluded that the change in the jet shape cone angle from 30' to 20'should have been classified as an USQ. Recommendations were provided r

from their review and they are being addressed by FPC's corrective action program.

Considering the lessons-learned from this experience, FPC has undertaken the following actions.

FPC personnel in the Nuclear Licensing Department and the Engineering Department's Safety i Analysis Group were provided. additional: training' and guidance.regarding the use of rev G

methodologies and the potential i_mpacts to the established FPC licensing basis, la addition, CP-

' 213,l" Preparation of-a~ Safety : Assessment and Unreviewed Safety Question Determination t

= (SA/USQ)," is being revised to include similar guidance. CP-213; Revision 5 will be issued by November' 14,11997.- LGuidance on this subject is being provided by the Nuclear Training

- Department for the initial qualification of personnel who will perform 10 CFR 50.59 cvaluations.

Personnel who cre currently qualified to perform 10 CFR 50.59 evaluations will be provided.

additibnal guidance on this subject.

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jPage 3 of 4 TJET IMPINGEMENT ON'SW SYSTEMJ R

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. s FPC acknowledges that the presentation of theLissue provided in Reference I was not clearf It

is hnportant to state that the basis for the use of a 20*Lversus a-30'_ cone angle for the jet 1

timpingement analysis was based upon several fastors, First, the original licensing basis did not.

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. define all needed analytical inputs. Two critical parameters for impingement analysis were not :

' described in any of the CR-3 licw d or design documents. " Cutoff Distance" is a parameter

- jet (i.e., impingement effects on targets beyond this Lthat restricts the effective rangt J distance from the break planc do ;ot rr.ed to be considered), " Shape Factors" are a function of --

'the drag coefficient and are based on the geometry of the target. The shape factor can be used

. to reduce the effective impingement pressure.on a target.1Second, the use of a 20' cone angle t

is;aitechnically correct method with a defined criterion that is~ described in NRC issued

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documentation. FPC concluded that this was a correct methodology to employ rather than the other option of selecting and defending values for the cutoff distance and shape factor which -

iwere ne' documented in any FPC analysis or NRC standard. Reference to SRP 3.0.2 and 1;

- ANSI /ANS 58.2 was not intended to be the primary basis for using the 20' cone angle, as may have ~been 'aterpreted by the 'NRC. As stated earlier at the October 22, 1997, NRC/FPC meeting, the information provide 6 by FPC should have been more clearly stated.

Based on the third party conclusion that this change should be classified as an USQ if it were to be incorporated into the CR-3 licensing basis, FPC has retained an outside engineering

. company to perform an analysis of the related jet impingement effects on the Nuclear Services Closed Cycle Cooling Water (SW) System piping using the original 30' cone angle. The

. purpose of this analysis is to document that the SW System piping does not fail (lose pressure n

boundary) when the jet impinges on it. This analysis is projected to be completed by December 5,1997_. Therefore, FPC will resubmit our conclusions for response to the NRC's request for

- additional information regarding " Protection Against Dynamic Effects of LOCA" by December 18, 1997.

REACTOR COOLANT-HOT LEG NOZZLE GAP i

FPC has further evaluated previously relied upon boron precipitation prevention methods and

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'modifiedLthe methodology __ to address generic issues for-B&W type plants that have-been previously communicated to the NRC. The change in methodology revises the licensing basis

for CP.-3 and, therefore, requires approval by the NRC. On October 31, 1997, License JAmendment Request #223 (Reference 4) was submitted to the NRC requesting approval of hot

leg nozzle gap methodology las part of CR-3's licensing basis for boron precipitation mitigation,

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sThe license amendment addresses concerns raised by the NRC in the Integrated Performance Assessment; Program _ (IPAP) report which identified this matter as restart.

This license amendment request adequately addresses concerns raised by the NRC in Reference 1 for the use Eof hot.le;; 7zzle gaps.

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U.S. Nuclear Regulatory Commission 3F1197,

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SUMMARY

- As stated ' above,- the_10 CFR 50.59 program for CR-3 is sound and - effective.

FPC.

acknowledges the lack of clarity in presenting the issues to resolve the issues. The individual-

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issues.are being addressed.

Commitments contained in this letter: are described in the

-I Attachment, If you have any questions on these matters, please contact Mr. David Kunsemiller, Manager, Nuclear Licensing at (352) 563-4566.

Sincerely,-

. Ysibv Jo h J.11 olden--

Director -

Site Nuclear Operations

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. Attachment xc:- Regional _ Administrator, Region II Senior Resident Inspector NRR Project Manager

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ibi Nuclear Regulatory Commission Attachment 3F1197-2F

- Page 1 of 1 List of Regulatory Commitments The following table identifies those actions committed to by Florida Power Corporation in this document. Any other actions discussed in the submittal repre.,ent intended or planned actions

' by Florida Power Corporation. - They are described to the NRC for the NRC's information and --

are not regulatory commitments. Please notify the Manager, Nuclear Licensing of any questions.

regarding this document or any associated regulatory commitments.

COMMITMENT IMPLEMENTATION Revise CP-213 November 14, 1997 I

Complete an analysis of the pressurizer _ surge line jet December 8,1997 impingement effects using the original 30' cone angle and resubmit our conclusions for response to the NRC's request for additional information regarding " Protection Against Dynamic Effects of LOCA" 4

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