ML17201J331
| ML17201J331 | |
| Person / Time | |
|---|---|
| Site: | Dresden  |
| Issue date: | 06/29/1988 |
| From: | Siegel B Office of Nuclear Reactor Regulation |
| To: | Bliss H COMMONWEALTH EDISON CO. |
| References | |
| TAC-67562, TAC-67563, NUDOCS 8807120378 | |
| Download: ML17201J331 (5) | |
Text
Docket Nos.:
50-237 and 50-249 Mr. Henry E. Bliss Director of Nuclear Licensing Conunonwealth Edison Company Post Office Box 767
. Chicago, Illinois 60690
Dear Mr. Bliss:
Juen 29, 1988
- DISTRIBUTION
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NRC & Local PDRs PD3 r/f*
LNorrholm GHolahan PD III-3 Grey.file BSiegel OCG-OWF EJordan BGrimes ACRS (10)
LLuther BSiege.l
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SUBJECT:
PROPOSED LICENSE AMENDMENT FOR 4KV UNDERVOLTAGE RELAY SETTING (TAC NOS. 67562, 67563}
Dresden Nuciear Powe~*station, U~it Nos. 2 and-~
'Re:.*.
- By letter dated March 28, 1988 Conunonwealth'Ed,ison 1Company ~ubrriitted,a request to amend the Technical Specifications regardfog. the 4K:V* under. voltage relay*
setting.
Based on its review and* concerr:is.,expre.ssed i;n**\\he 'M!irch* 22, ~,198~
conference call the staff has deter-mined thcit the.. informa.tfon!describea in'1the" enclosure will be needed to.. complete thfs 'review.*.; It ~.is '.'requested. that this information be provided.within 45 days)'ofjtie.fec~fpt 1'of i'thi,s
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.. Byron Siegel, P.roject Manager Project Di recto.rate I Il-2 Divis io.n *of Re'actor* Projects I II, IV, V
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Enclosure.
As.stated
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Docket Nos.:
50-237 and 50-249 DISTRIBUTION Docket Fi 1 e*.,
NRC.& Local PDRs PD3 r/f L~orrholm GHolaHan OCG-OWF Mr.* Henry E. Bliss Director of Nuclear Licensing C~munonwea lth Edi son. Company Post Office Box 767 Chicago, Illinois 60690
Dear Mr*. Bl i SS:
PD. 111"!3 Grey file BSiegel
- EJordan BGrimes ACRS { 10 LLuth BSi el I
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SUBJECT:
- PROPOSED LICENSE AMENDMENT FOR '4KV UNDERVOLTAG (rAc NOS. 67562, 67563)
. Re:
Ores.den Nuclear Power *St~ti()'n,..Unit Nos
- By letter dated March 23, 1988 Commonwe!llth Edi Company submitted a request to amend the Technical Specifications regarcp the*4KV under voltage relay setting.
Ba~ed. on its review ahd conc~rns:~. ressed in the March 22, 1988 conference call the *staff.has determined t t the information described in the*
enclosure will be needed to complete this review:
It~-is. req~ested that this information.be provided within 45. days the receipt.of t'his Jetter.
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- The reporting and/or recordkeeping r uirement~ contained in. this letter *.
affect fewe.r.than ten resp*ondents;'.
e'refore, UMB clearance is*.riot required under P.L.96-511.
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Enclosure As stated
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ENCLOSURE RE~UEST FOR ADDITIONAL INFORMATION CONCERNING D ESDEN 2&3 TECHNICAL SPECIFICATION REQUEST FOR 4KV ONDERVO[TAGE RELAYS SETPOINT
REFERENCES:
- 1)
CECo letter, J. A. Silady to NRC, T. E. Murley, dated March 28, 1988, Proposed license Amendment.
- 2)
CECo memo documenting conference call between CECo, J. S. Abel, E. D. Eenigenburg, et. al. and NRC, G. M; Holahan, W. G. Gouldemond, et. al. on March 22, 1988.
- 3)
CECo letter, T. J. Rausch to NRC, P. O'Connor, dated January 6, 1982.
- 4)
CECo letter, T. J. Rausch to NRC, H. R. Denton, dated March 4, 1982.
- 1.
Reference 1, Section 2(iii) of attachment 2 indicates undervoltage trip at 2930 volts with +/-5% tolerance.
The negative tolerance will result in 2784 volts trip which is approximately 67% of 4160 volts (bus voltage).
CECo should confirm that this resulting voltage does not exceed the standard.
1 minute rating of any 4KV or lower rating, class lE motor.
- 2.
In the conference call (Reference 2)~ the staff identified their concern re-garding the instrument check and functional test frequencies of the under-voltage relays. The current revision of Dresden 2 and 3 technical specifica-tions, Amendment 90, requires functional test at each refueling and instrument check on a 3-month bases. This is contrary to CECo's statements in their
v earlier submittals to the NRC regarding the generic issue of degraded grid voltage protection and the staff's position on the undervoltage relay test frequencies.
In Reference 3, CECo stated, -
"However if the NRC cannot revise their position on Functional Testing, we would propose to test the relays by first pulling all the test switches on the required aux relays, and then activate the undervoltage relays to verify that on activations the required relay targets are received as designed.
Notwithstanding, the pro-posed monthly testing is time consuming and unnecessarily offers opportunity for a single spurious trip to remove a 4 KV bus's off-site power source on an operating unit.
As a minimum, we believe a quarterly surveillance would be more appropriate than a monthly surveillance."
In a subsequent submittal (Reference 4), CECo stated, "This amendment request incorporates Limiting Conditions for Operation, Trip Level Setpoints, and ~urveillance Requirements associated with the addition of degraded voltage relays *. An additional surveillance of th_e existing undervoltage relays has also been added at the insistance of your staff to further ensure the operability of the undervoltage relay contacts."
The staff position has been a monthly functional test and a daily check for both undervoltage and degraded voltage relays.
- 3.
Note 6 in table 3.2.2 of the proposed changes to the Technical Specification calls the emergency power source inoperable when either of the two associated
'.. loss of voltage relays or either of the two degraded voltage relays are found inoperable. This note needs clarification regarding the following two concerns:
(a)
An inoperable channel, unless annunciated, can only be found when tested for its functional capability, calibrated or, at least, by status check.
An early and accurate detGrmination of an inoperable channel should be ensured by the surveillance test requirements of the technical specifica-tions. The current revision of Dresden 2/3 technical specifications re-quires functional test & calibration on a refueling basis and instrument check on once/3 month basis. The safety implications of this concern should be adequately addressed by CECo.
(b) If either of* the two relays in a 2-out-of-2 loss of voltage or a 2-out-of-2 degraded voltage trip logic is found inoperable, the Tech-nical Specification Section 3.9.B allows plant operation to continue for seven days (LCO).
However, the note does not clarify whether the inoperative relay is placed in the "fail safe"mode to provide a trip signal in its associated 2-out-of-2 trip logic or the entire logic is being disabled.
If the entire logic is disabled in order to declare the emergency source (associated diesel generator) inoperable, the Dresden 2/3 design should provide an alternate protection of class lE electric equipment from the potential abnormal (degraded) offsite power source during the LCO period. Additionally, it is not clear as to why the associated EOG is declared inoperable when one of the two under-voltage relays is found inoperable.