05000263/LER-1979-023, Updated LER 79-023/01T-1:on 800103,one Fuel Type Noted to Exceed Max Allowable Max Average Planar Linear Heat Generation Rate Value & Another as Improperly Programmed in Plant Computer.Caused by Inadequate Review

Updated LER 79-023/01T-1:on 800103,one Fuel Type Noted to Exceed Max Allowable Max Average Planar Linear Heat Generation Rate Value & Another as Improperly Programmed in Plant Computer.Caused by Inadequate Review

ML112900974
Person / Time
Site:	Monticello
Issue date:	01/14/1980
From:	Nevinski D Northern States Power Co
To:	NRC/OI/RGN-III/FO
Shared Package
ML112900975	List: 05000263/LER-1979-023, Updated LER 79-023/01T-1:on 800103,one Fuel Type Noted to Exceed Max Allowable Max Average Planar Linear Heat Generation Rate Value & Another as Improperly Programmed in Plant Computer.Caused by Inadequate Review
References
LER-79-023-01T, LER-79-23-1T, NUDOCS 8001170425
Download: ML112900974 (5)

LER-1979-023, Updated LER 79-023/01T-1:on 800103,one Fuel Type Noted to Exceed Max Allowable Max Average Planar Linear Heat Generation Rate Value & Another as Improperly Programmed in Plant Computer.Caused by Inadequate Review

Event date:
Report date:
2631979023R00 - NRC Website

text

0 REGULATURY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION Nl3R:$0O117O'425 DOC,DA1I.: 80/01/1L4 NOTARIZED: NO D)OCKET #

PACIL:*50-263 Monticello Nuclear G6eneratinq PlantrVNorthern Stateo 050069o3

- A0TH9NAME-AUTHOR AFFILIATION NEV1rNSKID.E.

Norihern States Power Co.

FECIPONAME RECIPIENT AFFILIATION Region~ 3,C'cao Office of the Director SUBJECT: LER 79-023/01T-1:on 800103fduring normal operationpone fuel type Inoted to -exceed --max allowable MAPLHGR value & another as i mprop erly programmed in plant computer.Caused by inad~equate internal & external review.,

DISTRIOUTION CODE: A00Z5 COPIES RECEIVEO:LTR

/ENCL S

Z4.A TITLE:

ln6identiR6po-rts-REC I PIENT ID CODE/iAME AC-ION:

05 8-'

INrERNAL: 04 ciiIIEi I 14 tA/EDO 16 eEB lb PL.ANT SYS bR 20 AD PLAN IsYi' 23 ENGIR OR 25 PV'jRSYS 6HN 7 OPERA LicB8R 29 AUX SYS TBR HANAUERF-S.

STS G~ROUP LEADR COPIES LTTR-ENCL 4

4 1

2 1

1 1

i 1

1 1

1 1

1 I

1 I

1 i

1 1

1 1

1 1

RECIPIENT ID CUOE/NAME 02 NRC PDR I! MPA 15 NUVAK/KNIeL 17 At' FOR ENGR 19 L&C'sYS-6V 42 kEAC SAFT BR 24i KREGER*

26 AD/SIT E ANAL 28 ACDENT'A.NLYS E JURDAN/TE' R IRELAND-COPIES 1

3 1

1 1

i I

1 I

I 3

1 3

i 1

i 1

1 i

1 i

3 EXTERNAL:

03 LPDR 29 ACRS 16 16 014 NSIC

- JOTAL NUMBER UF -CUPIES.*REUIED; Ll'1R NL 1

1 50 ENLL so

I.,

0 0

MSP NORTHERN STATES POWER COMPANY MINNEAPOLIS. MINNESOTA 55401 January 14, 1980 Mr J G Keppler Office of Inspection & Enforcement U S Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137

Dear Mr Keppler:

MONTICELLO NUCLEAR GENERATING PLANT Docket No. 50-263 License No. DPR-22 MAPLHGR Exposure Oversight - Update The Licensee Event Report for this occurrence is reproduced on the back of this letter.

Enclosed are three copies.

This event is reported in compliance with Technical Specification 6.7.B.1.i.

Yours very truly, LO ayr, M) er of Nucleat Support Services LOM/JAG/ak cc:,Z rector, IE, USNRC (40)

Director, MIPC, USNRC (3)

MPCA Attn:

J W Ferman

- over-8001 17i0+j,

7 [ED 7

8 CONT 10 1

7 8

7 8

7-8 and safety. No previous similar occurrences.

0 80 SYSTEM

CAUSE

CAUSE COMP.

VALVE CODE CODE SURCODE COMPONENT CODE SUBCODE SUBCODE I' ID (D [X0@ L](

Iz I zIIZ ZI

[

z LLJ[

9 10 11 12 13 18 19 20 SEOUENTIAL OCCUnRENCE REPORT REVISION LER /RO EVENT YEAR REPORT NO.

CODE TYPE NO.

EDIN LUMLJ L-J 10 12 13 L1 lo IT I Lj LiJ

. 21 22 23 24 26 27 28 29 30 31 32 ACTION FUTunE EF, ECT SIHUJTOOWN ATTACHMENT NPRO 4 PRIME COMP.

COMPONENT TAKEN ACTION ON PLANT METHOD HOURS SUIlMITTED FORMbUll.

SUPPLIER MANUFACTURER W0L @3 L0l oo 0 1 1 [1@0 L J Li Iz L2 33 34 35 36 37 40 41 47 43 44 47 CAUSE DESCRIPTION AND CORRECTIVE ACTIONS Occurrence was caused by inadequate internal and external review.

Corrective actions

include changes in plant process computer constants, discussion with fuel vendor.

I determination that future analysis/review methods prevent recurrence and procedural changes to increase nodal exposure monitoring. See additional pages attached.

7 8 9 FACILITY STATUS

%POWER OTHER STATUS

[

@ 1 01 81 6 B NA 1

8

10) 12 11 44 ACTIVITY CONTENT 1FI.EAS:D OF IIELrAS AMOIJNIOr ACTIVIT Y III3 4i -I~

NA af LzJI z g

&N I

7 8

9 to 11 44 PERSONNEL FXPOSUIIES NIJMIBER TYPF I)ESCIlIPTION S O

1 0 1 j0(DI Z J NA 8

9 11 12 13

'PERSONNEL INJU1lICS NUMREA DESClIPTION 41 0 10 10 l(11 NA 8

9 It 12

- LOSS OF OIl DAMAGE TO FACILITY TYPE

DESCRIPTION

1 I I NA B

9 10 P111 I)IICI I Y I' 1UFI)

IIErCIIIPI1ON q i f 1 1li NA 8

9 to NAME Or PD.EPAllED E.

Nevinski METHOD OF DISCOVERY DISCOVERY DESCRIPTION [I Cj(

Review of existing data 45 46 8

NA LOCATION OF FIELEASE 45 0

0

___]

80 80 80 80 NIIC USE ONLY GB 69 80 9 PHONE:

612/295-5151 Ex. 118 0

0,~V 4Z5 to

• 1 I

12 13 14 I

LICENSEE EVENT REPORT UPDAfE REPORT - PREVIOUS REPORT DATED 12/28/79 CON ill I III o:K:

(

0 1I I.A!.I. lIIINI (Il I VIL At L ILOtIIIIi 1) INI lIIMAIION)

IM IN I I P 1 1 01 0 l 0j 1 0 10 10 1 01 0 I jjjjj4 1 1Q II I

LICENSEE CODE 14 15 LICENSE NUMIILII 25

)6.

LICENSE TYPE JO 57 CAT bB S

L 0 IS 10 10 10 12 16 13 I0 l1 10 _3 18 10 0 l0l 1 14l 8 1 0 60 61 DOCKET NUM3ER (18 69 EVENT DATE 74 75 REPORT DATE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES During normal operation, discrepancies were discussed between peak planar exposure of two fuel types and the max. allowable values in T.S. Table 3.11.1. One fuel type exceeded the max. value in the Table; a second had the max. allowable value improperly programmed in the plant computer. Actual MAPLHGR values for both fuel types have always been and continue to be below allowable max. values. No effect on public health L

Page 2 of 3 LICENSEE EVENT REPORT Cause Description and Corrective Actions:

NSP/GE discussions regarding the Extended Burnup Program originated in 1978.

During the first half of 1979 MAPLGHR analysis was completed by GE for the Reload 2 fuel (designations "iTB") to extend exposure from 30,000 MWD/ST to 45,000 IND/ST.

Results were submitted to NSP in a DRAFT report [NEDO-24202) dated June, 1979. Subsequent to the required NSP reviews, the report was sub mitted to NRC dated September 17, 1979. Discussions in December, 1979 with NRC regarding the current and expected maximum bundle average, maximun average planar, and maiimum local pellet exposures led to the observation that EOC-7 exposures, as projected by GE, appeared to be high.

Specifically, maximum average planar exposure of 38,360 MWDAIT converted to 34,870 MWD/ST, and this was above the highest value listed in the MAPLHGR table (Table 3.11.1 in the Technical Specifications) applicable to the current operating cycle (7).

It was confirmed by interrogating various process computer edits and BUCLE edits that current nodal exposures at several core locations were above 30,000 MWD/ST.

BUCLE (Backup Core Limits Evaluation) edits are obtained from the GE Mark III System approximately twice each month. BUCLE automatically prints out the high est nodal exposure in the core, information which is also available via the pro cess computer (P/C), but not directly edited by any program. A review of BUCLE edits indicates peak nodal exposure on April 11, 1979 below 30,000 MWD/ST and on May 1 it was at 30,028 MD/ST.

Therefore, May 1 may be indicated as the time in CYCLE 7 when planar exposure first exceeded 30,000 MWD/ST.

Evaluation of actual MAPLHGR data from the P/C for Reload 2 (MTB fuel) while the plant was operating at or near 100% power indicates the following:

ATE MAPLHGR NODAL EXPOSURE CORE LOCATION kft.E)

(ID/ST) 5-2-79 8.14 25,881 41,28,6 6-1-79 8.06 26,749 41,28,5 7-2-79 7.55 25,911 11,28,5 8-1-79 6.97 26,655 11,28,4 9-5-79 6.97 27,633 35,24,.12 10-1-79 6.91 26,872 37,26,15 11-2-79 7.81 27,283 37,26,16 12-3-79 6.96 28,521 37,26,15 12-10-79 7.11 28,683 37,26,15 12-17-79 6.79 28,864 37,26,15 The Extended Burnup Program I4APLHGR analysis for 141B fuel indicates a maximum allowable value of 9-8 kw/ft. at 35,000 MD/ST.

The information above then suggests two things:

1. At no time since 30,000 MWD/ST was exceeded did the MAPLHGR exceed the analyzed limit; thus, no Limiting Condition for Operation (LCO) was violated.

2. The MAPLGHR always occurred at core locations having lower exposure than the peak exposure; specifically, the exposures in locations where MAPLGHR has occurred for the MB fuel have continually been below 30,000 MWD/ST since May 1, 1979.

Because of the above two conclusions, the occurrence has no consequence from the standpoint of public health and safety.

Sage 3 of 3 LICENSEE EVENT REPORT Supplementary Information - UPDATE REPORT As an outgrowth of continuing investigation of MAPLIGR and exposure values for fuel presently in the core, it was confirmed on January 3, 1980, that the maximum exposure programmed into the process computer for the.8DB219L fuel ("LJ2000") and 25,000 MWD/ST, though Table 3.11.1 in the Technical Specifications allows a maximum of 30,000 MWD/ST. Actual peak planar (nodal) exposure for this fuel type was found to be 27,000 MVTD/ST. Appropriate MAPLHGR limits are 10.6 KW/FT at 25,000 and 10.2 KW/FT at 30,000; the computer continued to apply the 10.6 limit between 25-27,000, whercas interpolation between 10.6 and 10.2 should have been applied.

At the time 25,000 MWD/ST was exceeded in mid-November, 1979, the MAPLHGR was 7.31 KW/FT-for the 8DB219L fuel. From that time until the present the plant.as been in coastdown with all rods out.

The present MAPLHGR value for this fuel is 6.81 KW/FT. Again, as with the MTB fuel, no LCO was violated. The occurrence has no consequence from the standpoint of public health and safety.

Corrective action has beencompletedas follows:

1. The plant process computer has been reprogrammed with appropriate constants for both MTB and LJ 2000 fuel.

This corrects the current situation with adequate exposure margin through the end of the current operating cycle.

The bases for these changes are contained in GE document NEDO-24202, which has been submitted to NRC in a License Amendement Request dated September 21, 1979, in support of the Extended Burnup Program at Monticello Scheduled to begin with the upcoming operating cycle in 1980.

NOTE: A check of bundle and nodal exposure arrays has been completed for all other fuel types in the core with the determination that no other fuel type will exceed 30,000 MWD/ST through the remaining of the current operating cycle.

2. A Technical Specification License Amendment Request dated December 21, 1979, has been submitted to change Table 3.11.1 by adding the values shown in 1., above.

3. A letter has been written to GE requesting determination that review methods be revised to assure prevention of a similar future occurrence.

Additionally, the letter suggests a permanent software change to the pro cess computer to edit maximum planar exposure for each fuel type, as well as the currently programmed maximum value of planar exposure, with each MAPLGHR interrogation of the computer by operating personnel.

4. The monthly Reactivity Anomaly surveillance test completed by the nuclear engineers and reviewed by the Supt., Technical Engineering, has been revised to include a verification, with documenation, that the maximum planar exposure of each fuel type in the core is less than the maximum value listed in Technical Specification Table 3.11.1.

An additional change will be made to the monthly reactivity anomaly proce dure to check that process computer exposure constants are, and remain, in accordance with Technical Specification Table 3.11.1.