ML20055C248

Forwards Comments on Electrical Matters Considered During 890510-12 Insp at Plant.Reason for Delay Stated

ML20055C248
Person / Time
Site:	FitzPatrick
Issue date:	08/03/1989
From:	Morris C Office of Nuclear Reactor Regulation
To:	Thomas Koshy NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I)
Shared Package
ML20055C249	List: ML20055C248 ML20055H890
References
FOIA-90-319 NUDOCS 8908080027
Download: ML20055C248 (6)

Text

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,I MEMORANDUM FOR: T.-Koshy f Region !

Faust Rosa, Chief

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Clectrical Systems Branch p

'$y.. Division of Engineering & Systems Technology a .

? FROM: Charles Morris Electrical Systems Franch E. Division of 2nginer. ring & Systems Tecnology (l.

SUBJECT:

COMMENTS . J. A. FITZPATRICK NPP ON MAY 10-P.1989 1

The enclosure attached giv9s my connents on those eiretrical matters'

- if considered by me during ny site visit in May 1989 with your inspection team.

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'l They have been delayed by other reviews for nuclear power plants awaiting

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j. sttrtup and by the need to review. Stone & Webster (SWEco) calculations 26-01

- and 26 02, and other submittals from the licensee, c ,

1 Charles Morris Electrical Systems Branch--

Division of Engineering &. Systems Technology

Enclosure:

As stated ~

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' D. LaBarge i Distribution:

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C. Morris (PF)(2)

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e I h*~. COMMENTS OF'C. MORRi$ ON INSPECTION _ '

Ib:' AT J. A. F11ZPATRICK NPP-

. ON MAY 10-12.1989

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y!. 1. In their January 6.1989 letter JPN-89 001, the New York Power Authority

[ (NYPA) listed in Attechment I, PARTIAL RESPONSE TO REQUEST FOR ADDITIONAL

lNFORMATI0tt TRANSFER OF RESERVE POWER TO EMERGENCY BUSES, nine instances

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of-inoperable Emergency Diesel Generators. None of these nine events is

[ included in the list of 15 slow manual transfers (same document). Did

{.y F J. A.- Fitzpatrick (JAF) violate Technical Specification (T/S) section

'1 3.9.B.3 in that they did not transfer to the 11SkV Offsite Power Supply g (OPS), as required, or did JAF send to'the NRC invalid data, intended for j evaluating Slow Manual Transfers (SMT) from 0hsite to 0ffsite Power? . The data submitted is invalid, because nine out of 24 known transfers are not described-for 1984-1989. Additionally, the lists did not tabulate SMT fromthePreferredPowerSupply(PPS)totheNormalPowerSupply.(NPS),

on start up.

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-2. Staff agrees with DEVIATION 88-23-02, in that continuous indication of operational status of the OPS is required in the Control Room of JAF.

Open circuit voltage and the status of some of the Offsite PS breakers is-not' sufficient in that :hese alone do not' reveal PFS inoperability to JAF-operators.

The Niagara Mohawk Energy Control Center disp 0tcher has continually avail-able the status of all Reserve Power Supply (RFS) 115kV breakers, transmis-1 sion lines, transformers, generators, and loads. With this information, he or the control room staffs of, the three Nine Mile Point nuclear _ power-l stations cea determine that the design basis loads for the RPS for any one or all three of the nuclear units can be serviced, or that the RPS capability.

is in, or is approaching, a marginal state, or in fact is less than fully capable.

The capability of the RPS should either be continuously available in the

' three Nine Mile Point control rooms, or there should be a conditment from the !!!agara Mohawk Power Co. to notify the three control rooms whenever the RPS is not, or may not long be, fully capable, and to do so in a timely oanner,

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3.- It is the opinion of the staff that JAF and the two Nine Mile Point Units.

'.g'g) must' coordinate better than has always been the case, the operation of the Pi L three nuclear power plants on what is, de facto, one site, despite organiza-h tional boundaries. NYPA and Niagara Mohawk Power Co. (HMPCo) should be re-h .c quired to-submit such a coordination plan to Region I.

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4. System Interconnection Figure 8.3-5, _FSAR shows the NMP-JAF No. 4115kV fjj transmission line (TL) crossing NMP-2115kV and 345kV TL to the SCRIBA

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Substation and crossing hMP-1 345LV TL. Are these crossings protected

$. so that one required line is not taken out by another falling line?

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5. Licensee submittals Transfer of Reserve Power to Emergency Buses (JPTS 85-15)

[U April 27, 1989, and Proposed Change to the Technical Specifications Regarding a Second Time Delay for Actuation of the Degraded Voltage Protection System

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(JPTS-88-011) August 24, 1988, whilo resolving some staff concerns about OPS

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adequacy have not resolved others which will be the source of an RAI.

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6. The description of the JAF Startup Procedure does not;give sufficient i assurance to staff that equipment connecting the safety buses to the OPS will not be damaged because: The Startup Procedure'says that the

' control room operator will estimate the phase difference _between the'NPS

" and.RPS and get the Station Manager's permission to proceed, if the angle exceeds 17'. Ho basis in the calculation, or elsewhere, has'been given F for allowing the Station Manager to give such permission. And there is no procedure for limiting the time during which the live bus is connected ~

- to two power supplies, beyond the trips which may be induced by undervoltage relays or breaker overcurrent settings. The verb estimate in the Startup Procedure implies that there is either an insensitive indicator with insuf-k ficient resolution or a noisy signal - neither is desirable, nor is either h,<!

y necessary.

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7. During live bus transfers between normal station service transformer (NSST)

N 1 andreservestationservicetransformer(RSST),theinterruptingratingof

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breakers may be exceeded; and the'iault current ratings of buses and SWEco calculation (26J01) mentions this condition, but does not' g[ formers.

otherwise address it ' nor has JAF,

%M.) Licensee has not provided a complete description of the 115kV RPS which

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would' allow a reviewor to' determine'that it is fully capable in different-h

v. RPS operating modes and that low voltages on bus 10400 on start up are not g3 due to insufficient'T4 tap changing range, or low voltage on the RPS.

If

?l, j; the RPS voltage cannot be corrected by ' preset taps, because of changes in other loads than JAF on the RPS, i.e., changes exceeding 1.05 per unit, 3,[

then the RPS may not be fully capable of meeting GDC-17 requirements.-

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3 The stability study (NYPA memorandum from H. Henderson to L. Quaquil,

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April 26.1988) shows that rotor oscillations and. amplitude oscilla-d.) tions on the 345kV system are bounded and damped. But, because of

[ the large time steps,1.5 seconds per division, the first ten cycles

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of inhibited fbst transfers between NSST and RSST cannot be answered by

[ this study.

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SWEco Item E-77 page 1 says, "The 115kV bus is an infinite bus because the Lighthouse Hill line has voltage regulation." This is only true for intervals greater than the time constant of the regulator and only true-at JAF, if the feedback signal is derived from JAF and not at the Light-house Hill transformer, and if it is within the ar.plitude range of the

( regulator.

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31. Page 5 of JAF-SE-85-118, Attachment B statement that needs explication; h to wit: "When these factors are applied to the' ainimum allowable value, L

w a minimum trip value of 108.0V is determined. When the above factors y are applied to the maximum allowable value, a maximum trip value of y[ Because of the narrow seating band, no' margin is 108.1 is established.

3 (I.f - applied for the minimum trip value." An operating band of less than Presumably something else is t.1V at 108V (s.0C pu) is not feasible.

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4.t T #$ 12.; On page 1 of. Attachment to JPN-89-021 REQUEST FOR ADDITIONAL INFORMATION,

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.TRANSTER OF RESERVE POWER TO DIEP.GENCY BUSES (JPTS 85-15) .... ' April 27,

' hf,I 1989, NYPA cited ANSI standards C57.92-1981.as the guidance for calcula-

, jid- tions (also'not provided) which show.that the maximum NSST and RSST trans-

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C formr hottest-spot temperatures were 73'C (rising from an initial temper ,

atureof30'C). ANSI standard C57.92-1981 is not the appropriate standard v

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$ for this purpose, because:

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- 1. The subject standard is intended to calculate hottest-spot degrada-l' i ' tion of distribution and power transformers for daily load cycles, '

greater than 1/2 hour duration, with peak loads less than'2X rated.

h Applying such guidance to 10 sec. intervals, say, five times a year,

.9 at current levels of 3X rated, may or may not be conservative.

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i g 2. If the calculations citad in JPN-89-021 were done in accordance with the equations of Section 6.7 of ANSI C57.92-1981, licer.see L ) should-demonstrate that the characteristics of T2, T3, and T4'

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E were used. The data carried in the largely illegible Trans-former Test Reports is not applicable.

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b ~. 3. In IEEE Transactions on Power Apparatus and Systems, Vol. PAS-104, l +

1. 8, August 1985, Development And Application of Fault-Withstand' e- Standards for Power Transformers, C. H. Griffin wrote: "Under .

L these new standards transformers were divided into the following

. categories: [1,..IV (above 30 MVA for a three phase transformer).

For all other categorics ... the duration of the short circuit

, current [here the overload current) is limited to two seconds

f. unless otherwise specified by the user."

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q 7 "It is interesting to compare these requirements with tho,se of O

• the old C57.1200 ... RMS Synnetrical Current in Any Winding, k 14.3 or less times base current ... [neximum] time Period in' Seconds, 5."

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, C The appropriateness of limiting overload currents of three times rated to five I seconds or ten seconds is questionable considering other factors . cited in if,  ;

C57.1200-1987 and C57.92-1981, IEEE Guide for Leading Mineral-011'Imersed L' .'

l Power Transformers Up to and Including 100 MVA t,1th 55'c or 65'c Average Winding (

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Rise, but is probably acceptable. However, l'censee should be asked to submit .

1 calculations showing 73'C hottest-spot temperature ar.d consideratica of the any cautions and limits cited in .these two stand ards.

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An alternative to calculations based on standards of arguable relevance, or j

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on uncertain transformer parameters, and a more satisfactory alternative deter-mination of stress-degradation of electrical components exposed in SMT than calculations would be the operating record, if it can supply the reliability o of'these components. Supposing 5 SMT per year with 4 paralleling interva?s each over (1989-1975) 14 years, 280 incidents of parallel NSST and RSST sho11d show a;need for concern, if any exists.

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