ML20006E265

Provides Addl Info Re Environ Qualification of Gammametrics Neutron Flux Detectors at Facility & Revises Util Conformance to Reg Guide 1.97 Submittal.Leaking Cable Assemblies Will Be Repaired/Replaced,As Necessary

ML20006E265
Person / Time
Site:	Fort Calhoun
Issue date:	02/09/1990
From:	Gates W OMAHA PUBLIC POWER DISTRICT
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
RTR-REGGD-01.097, RTR-REGGD-1.097 LIC-90-0084, LIC-90-84, NUDOCS 9002220481
Download: ML20006E265 (4)

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Omaha Public Power District '

, 1623 Hamey Omaha, Nebraska 68102 2247 '

402/536 4000 February 9, 1990 (

LIC-90-0084:

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l l U. S. Nuclear Regulatory Commission Attn: Document Control Desk Mail Station P1-137 Washington, DC 20555.-

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References:

1.- Docket No'. 50-285 l l 2. Letter from OPPD (R. L. Andrews) to NRC (D. E. Sells) dated I October 21, 1986 (LIC-86-0532)

3. Letter from OPPD (R. L. Andrews) to NRC (H. R. Denton) dated j April 1, 1985 (LIC-85-117)

SUBJECT:

Gammametrics Cable Seal Repair l The purpose of this letter is to provide additional information regarding l Environmental Qualification of Gammametrics neutron flux detectors at Fort Calhoun Station (FCS)-and to revise Omaha Public Power District's (0 PPD) conformance to Regulatory Guide (RG) 1.97 submittal (Reference'2).

In May 1988, Gammametrics issued a 10CFR21 notification to the NRC identifying j

- potential' leakage problems in the solder connections of neutron flux monitoring i system detector / cable assemblies. During the 1988 refueling outage,

.Gammametrics personnel tested three of the four detector / cables systems

,- installed at FCS. All three assemblies were found to be leaking thereby l l~

invalidating their qualification status. As a result, OPPD prepared a Safety I Analysis for Operability (SA0) stating that environmentally qualified seal kits would be installed during the -1990. refueling outage.

Gammametrics completed environmental qualification testing of their new seal  !

design recently and issued a report. Based on our review of this report, OPPD '

Lhas~ concluded that the test does not meet the environmental qualification requirements of'FCS. The seal kits, therefore, will not be installed as

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originally planned. The leaking cable assemblies will be repaired or replaced  !

-as'necessary, in two of the four subject cable loops and will then be retested. Leaking in the replacement assemblies, if it should occur, will be  :

repaired.

All four wide range neutron flux monigoring channels are required to be operable for low power operation (10' to 15%) and two channels are required to be operable during refueling operations. Only two of the detectors, per RG 1.97, are required to be environmentally qualified to 10CFR 50.49 requirements  ;

for post-accident monitoring operation. OPPD's RG 1.97 compliance submittal o 44 &

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t U. S. Nuclear Regulatory Commission LIC-90-0084 Page 2 (Reference 3) took the position that the use of two completely independent channels. meets the intent of Category I redundancy requirements. However, the submittal identified all four of the wide range neutron flux monitoring channels as being available to meet this requirement. Consistent with the above requirements only two of the four channels will be restored to fully qualified status prior to stari up.

Attached are Section 5.1.1 and Table 1 of Reference 2 which have been revised I

to indicate the two detectors that will be environmentally qualified.

If you have any questions, please contact me.

Sincerely, m.D.Rr, W. G. Gates Division Manager Nuclear Operations WGG/pje c: LeBoeuf, Lamb, Leiby & MacRae R. D. Martin, NRC Regional Administrator, Region IV A. Bournia, NRC Project Manager P. H. Harrell, NRC Senior Resident Inspector 5

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1 5.1 Tvoe A Variables 5.1.1 Neutron Flux (CAT. 1)

The function specified above is performed by instrument loops N 002 and -004 made up of tho'excore detectors located in l 3

containment, amplifiers located in the Auxiliary Building and , ,

, ' Wide Range Log Channel Drawers located in the control room. Two source range monitors (SRM's) and two wide range instrument L ' monitors (IRM's) are provided for flux indication. All SRM and

, IRM detectors consist of dual fission chambers. The Excore

/ detectors were replaced during the 1984 outage with fully qualified components. The detectors, amplifiers, and cable assemblies are qualiffied to Reg. Guide 1.89 and 1.100 and with >

the methodology described in NUREG 0588, CAT I. However, the balance of the equipment such as the Wide Range Log Channel Drawers, which provide signal processing at.d indication for neutron flux, have not been upgraded and are in compliance with the requirements applicable at the time of issuance of the construction permit. The District believes the above deviations  !

from the requirements are justified as discussed in Section 2.3.3.A.1 of this report.  !

g Summary Position - The District believes that the existing  ;

instrumentation loops for neutron flux measurement are adequate to perform the intended accident monitoring function. Thus, no modifications are proposed.

5.1.2 Reactor Coolant System Pressure (CAT. 1)

The function specified above is performed by pressurizer pressure instrument loops P-105/P-ll5 and by proposed loops P-120A and P120B (scheduled to be installed during the 1987 refueling outage). These loops are in compliance with the requirements of Reg. Guide 1.97 Rev. 2 except as noted herein: '

This function is performed by P105/P115 pressure loops for the LOCA/MSLB bounded DBA events, and by P120A/P1208 pressureloops for the'ATWA bounded Design Basis Events (DBE).

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CafFARIScis OF FORT UURA STAf t0N tmIT 810. T f MSTittM IREPOETS TvPE A vARiAstES . - -

POWER .

INSTRtMENT E OA RANCE ENV CUAL. Sets QUAL. REDUND. SUPPLY RECORDifeC OtSPLAY LOCAT10s CopeOITS I. REACTIVITY CONTROL

1. Meutron Flum R.C. 1 -

100% CAT. 1 ~ R.C. 1.100 REQUlitED IE Required One Channel Continuous in cogtlance witsi enceptions noted la (NT-002, 004) OPPD 1 USAR 10p%-125%

10~ 10CFRSO.49 - BEEE-344-75** YES IE _ SPDS CR, SPDS Section 5.1.1 fl. RCS INVENTORY / PRESSURE -

CONTROL

1. Pressurizer Level R.C. 1 - 0-100% CAT. 1 . R.C. 1.100 REQUIRED IE Required One Channel Continuous la Comylf ance (LT-101X/Y) OPPD 1 USAR 0-100% 10CritSO.49 IEEE-344-75+ YES IE 1 Recorded . CR, SPDS

2. RCS Pressure R.C. 1 --

0 psig . . CAT. 1 R.C. 1.100 REQUIRED IE -Required one Channel Cont'inuous OPPD 0737 0737 0-2500 psfg IEEE-344-75* IE- See Section S.1.2

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. (PT-105,115) 10CFRSO.49 YES Recorded CR, SPDS (PT-1*0A, PT-1208) 1 0737 1900-2900 pstg 10CFRSO.49 IEEE-344-197S YES IE SPDS CR, SPDS , See Section 6.1.4

3. Degrees of Sub- R.C. 1 -

200*F to 35*F CAT. 1 R.C. 1.100 REQUIRED IE Required One Channel Continuous la Cepifance cooling (SPDS) OPPD 3737 0737 618*F sub- 10CFRSO.49 IEEE-3%-75 YES IE . SPDS. CR,SPOS See Section 5.1.3 cooled to 666*F super-beated N/R - Not Required.

+ - The entire Icop is not qualified to IEEE-34-1975, only portions, including the sensors are qualifted. . _ .-

• - The transmitters located in the harsh environment were replaced per 10CFRSO.49. The ne= transettters are quellf fed per IEEE-344-1975 and 10CFitSO.49. All other components of the loop are qualf fled per the seismic requirements which applied at the time the construction permit was issued. (Reference Appendix F of the USAR).

• • - The entire loop is not quallfied to IEEE-344-1975, only the encore detectors and ampitflers are quellfied. The balance of equipment is geallfled to original sefsnie qualiffeatson.

-- - CA requirements for categories 1, 2, and 3 are shown in Section 2.3.3.A.5.

R.C.- Regulatory Guide 1.97, Rev. 2 requirements.

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