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PWtR RESPONSE TO TIA 97419, SEQUOYAH NUCLEAR PLANT, '
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UNIT 1.-TECHNICAL SPECIFICATION REQUIREMENTS FOR
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' INITIATION OF PHYSICS TESTING (T. AC NO. M99588) '
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> ? f This is the Office ~of Nudoar Reactor Regulation (NRR) response to the request for technical assistance regen $ng interpretation of the intent of Sequoyah Nudear Plant Technical
' Specifice6on (TS) 4.10.3.2 NRR assistance was requested in Task interfeos Aersement (TIA) 97419 via memorandum from J. Johnson to~J. Zwoiinski dated September 3,1997. This response closes out TIA No. 97419.'.f;#.9;/ -
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Fotowing refueling of Sequoyah Unit 1 on May 11,1997, physics testing was initiated. TS Survoulance Requirement (SR) 4.10.3.2 requires performance of a CHANNEL FUNCTIONAL l
TEST (CFT) on the nudear instruments (NI) within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> prior to initiating physics testing.
4 Although CFTs had been conduded earter on the Nis, the 12 hour1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> period on at least one NI
. expired at 2:18 a.m. Although the operators dedared the initiation of phydce testing at 2:13 i
l a.m., actual control rod wahdrew! did not commence unth 2:40 a.m.,22 minutes ofter the expiration of one of the CFTs. Region 11 issued the Tennessee Valley Authorhy (TVA), the 6..
loonoce for Sequoyah, a Notice of Violation (NOV) in inspection Report 50 327, 328/97 04 g
dated ' June'20,1997, for failure to most SR 4.10.3.2. The licenses denied the violation in correspondence dated July 12,1997. This memorandum is written in response to your request
. of September 3,1997 for assistance in'eddressing the Econsee's denial of the violation. The
,Vprimary questions arel(1) when may the Econses dedare the initiation of PHYSICS TESTS.
TW%*rpnd (2) did the Boonoce property'dedare the initiation of PHYSICS TESTS in this instance?
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hfiW. point.;ln 'one instance, the 5censee's' procedures defins initiation of physics testing as when
$p%.M[wd.f:.:W':t-r. from the SRO has beoriobtained to begin the first rod w d'$i' N$%@& Sdual rod wthekowel. Another definition could conceivably include the dat li;.everage nuclear inetniment baseline count rate prior to the putin0 of control banks. The staff
/ I ty$$pNJMMdoes not have a prefersnoe Ibr the.epedflo point at which the initiation
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- m. The staff does believe that the initiation point should to consciously, logicolty and consistently determined. There should not be a conmet totween procedures, as there appurs to be in this case.
In the sm -tion involved, the scenew chose to declare that physics tests were inittsted when the S5 J gave permission to begin the withdrewal of control bank A. In and ofitself this is not a problem. In granting permission though, the SRO must ensure that the control bank is capable of both physically and procedurally being withdrawn. In this case, it appears that the SRO grantad permission for control bank A to be withdrawn before necessary procedura! revisions were approved merely to meet the TS SR requirement for completing the Ni CFT within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> prior to initiation of physics tests. In such a case, a violation could be issued. We understand, however, that the Omes of Enforcement may desire to exercise enforcement disc.ition and withdrew the c#ation.
N you have any questions, please contset the Sequoyah Project Manager, Ronald W. Heman at (301) 415-2010.
Docket Nos. 50 327 and 50-328 cc: C. Hehl, Region i O. Grant, Region ill T. Gwynn, Region IV 6
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J. Johnson 2-declared. The staff does beneve that the initiation point shouki be consciously, logically and consistently determined. There should not be a conflict between procedures, as there appears to be in this case.
In the situation Irwolved, the Econses chose to declare that physica tests were initiated when the SRO pave permission to begin the withdrawal of control bank A. In and ofitself this is not a problem. In granting permission though, the SRO must ensure that the control bank is capab's of both physically and procedurally being withdrawn. In this case, it appears that the SRO granted perrnission for control bank A to be withdrown before necessary procedural revisions were approved merely to rnoet the TS SR requirernent for completing the Ni CFT within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> poor to initiation of physics tests. In such a case, a violation could be issued. We understand, however, that the Office of Enforcement may desire to exercise enforcement discretion and withdrew the citation.
5 ff you have any questions, piease contact the Sequoyah Project Manager, Ronald W. Heman at (301)415 2010.
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' Docket Nos. 50-327 and 50 328 cc C. Hehl, Region i original signed by F.Hebdon G. Grant, Region ill T. Gwynn, Region IV.
Distribut!on:
Docket File JLieberman SQN Reading MBoyle (MLB4)
BBoger MShannon, Ril JRoe TUu SRichards WBeckner DOCUMENT NAME: G:WQNt99548.TIA To receNo a copy of this document. inecote in the bou C= Copy w/o suschmenvendoeuro E= Copy with anactwwWondoeurs N = No co:y j
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MTE 100[/97 10/fi/97 10/,fD97 10tf/97 OFFICIAL RECORD COPY
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UNITED STATES y
P; NUCLEAR RESULATORY COMMISSION i
WASHINGTON, D.C. SOASHopt o*****e February 4, 1998 Mr. John K. Wood Vice President - Nuclear, Davis-Besse Centerior Service Company l
c/o Toledo Edison Company j
Davis-Besse Nuclear Power Station l
l 5501 North State Route 2 Oak Harbor, OH 43449-9760
SUBJECT:
DAVIS-BESSE NUCLEAR POWER STATION, UdIT 2 - INTER N ETATION OF SCHEDULE REQUIREMENTS FOR TECHNICAL SPECIFICATION SURVEILLANCE TESTS CONDUCTED ON A STAGGERED TEST BASIS (TAC NO. MA0163)
Dear Mr. Wood:
i This document has beer, prepared in response to your letter (enclosed) dated November 3,1997, in which you requested the Nuclear Regulatory Commission (NRC) staff to provide an interpretation of schedule requirements for Technical Specification (TS) surveillance tests conducted on a staggered test basis at the Davis-Besse Nuclear Power Station.
Backaround Davis-Besse TS 1.0, " Definitions," defines staggered test basis as,follows:
STAGGERED TEST BASIS 1.21 A STAGGERED TEST BASIS shall consist of:
a.
A test schedule for n systems, subsystems, trains or designated components obtained by dividing the specified test interval into n equal subintervals, j
b.
The testing of one system, subsystem, train or designated j
components at the beginning of each subinterval.
l Davis-Besse TS 4.0.2 states:
4.0.2 Each Surveillance Requirement [SRy shall be performed within the specified time interval with a maximum a lowable extension not to exceed j
l 25 percent of the specified surveillance interval.
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TS Bases 4.0.2 states, in part:
l 4.0.2 The provisions of this specification provide allowable tolerances for performing surveillance activities beyond those specified in the nominal surveillance interval....It is not intended that the allowable tolerance be used as a convenience to repeatedly schedule the performance of surveillance at the allowable tolerance limit.
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Since TS 4.0.2 cannot be used on a routine basis, a test (say, on Channel 2)
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conducted subsequent to the application of TS 4.0.2 would still have to be performed again in the next subinterval as previously scheduled (for j
Channel 2). For example, if the entire 8-day extension was utilized for the test of Channel 2, then the next test of that channel would have to be performed in 24 days, as shown by the following table:
DAr thannP.1 8
1 completed (normal schedule) 16 (2 scheduled, not completed, TS 4.0.2 invcked) 24 2 completed (including TS 4.0.2 25 percent extension) 3 completed (normal schedule) 32 4 completed (normal schedule) 40 1 completed (normal schedule) 48 2 completed (return to normal schedule) 56 3 completed (normal schedule)....
The above interpretation applies to Davis-Besse. For plants that have adopted
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the improved Standard Technical Specifications (iSTS), SR 3.0.2 (which provides for a 25 percent extension similar to Davis-Besse TS 4.0.2) specifically refers to the frequency which, due to the changed definition of staggered testing in iSTS, is the subinterval. Therefore, the above interpretation does not apply to plants that have adopted the iSTS.
Please contact Allen Hansen of my staff at 301-415-1390 if you have any questions.
Sincerely, Original signed by D. Pickett for:
Richard P. Savio, Acting Project Nrector Project Directorate III-3 Division of Reactor Projects III/IV l
Office of Nuclear Reactor Regulation
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l Docket No. 50-346
Enclosure:
As stated l
cc: See next page i
DISTRIBUTION:
Docket File PUBLIC JLieberman JZwolinski PD3-3 R/F EAdensam (EGA1)
HICB/DRCH RSavio JJohnson, RII TSB DGC GGrant, RIII MBoyle (MLB4)
ACRS SCampbell, RIII SBloom (SDB1)
CHeyl, RI TGwynn, RIV SRichards DOCUMENT NAME: G:\\DAVISBES\\DBAOI63.LTR
- See previous concurrence OFFICE PD33:LAl C PD33:PMl HICB:BC l TSB:BC e J PD33:PDl.C.
NAME EBarnhillEdr AHansen JWermiel
- WBecknef "
RSavitPV V DATE cQ/3 /9f t-/ 5 /97 1/27/98 A/t4 / '11
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OFFICIAL RECORD COPY W6?ed GuC 4 ~ f S
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J. Wood,
Reauest for Interpretation You requested an interpretation from NRC on the appropriate application of the l
25 percent maximum allowable extension (TS 4.0.2) to TS surveillance testing performed on a staggered test basis.
Interpretation As an example, consider a 4-channel system with channel functional testing required to be performed once per 32 days on a staggered test basis (32 days chosen for mathematical simplicity). Per TS 1.21:
Subinterval - 32/4 = 8 days If a functional test is not performed within the 8 days, then TS 4.0.2 allows l
up to a 25 percent extension.
In your letter, you offered two possible interpretations of the application of TS 4.0.2:
(1)
Since each channel must be tested once per 32 days, then TS 4.0.2 allows:
Extension - 0.25
- 32 - 8 days (2)
Since each subinterval requires testing each 8 days, then TS 4.0.2 allows:
Extension = 0.25
- 8 - 2 days.
For the Davis-Besse TSs, the staff has determined that the 25 percent extension of TS 4.0.2 addresses the overall length of the surveillance interval, while the subintervals of the staggered testing definition only deal with how the beginning of the overall intervals for different subsystems are arranged. Therefore, TS 4.0.2 should be applied to the overall interval requirement. Thus, as in the example above, Extension = 0.25
- 32 - 8 days.
You also state in your letter that:
...the intent of perfoming testing on a staggered basis is to limit the length of time that a common cause system failure could go undetected.
Though staggered testing does have a benefit with regard to reducing the risk due to common cause failures, it also provides for operational convenience.
The requirement in the Davis-Besse TSs to perfom designated testing on a staggered basis (each 8 days in the example above) does not take precedence l
over each system-specific surveillance requirement to test all channels within the specified interval (32 days in the example).
J. Wood,.
i Since TS 4.0.2 cannot be used on a routine basis, a test (say, on Channel 2) conducted subsequent to the application of TS 4.0.2 would still have to be performed again in the next subinterval as previously scheduled (for Channel 2).
For example, if the entire 8-day extension was utilized for the test of Channel 2, then the next test of that channel would have to be performed in 24 days, as shown by the following table:
l Day Channel 8
1 completed (normal schedule) l 16 (2 scheduled, not completed, TS 4.0.2 invoked) 24 2 completed (including TS 4.0.2 25 percent extension) 3 completed (normal schedule) 32 4 completed (normal schedule) 40 1 completed (normal schedule) 48 2 completed (return to normal schedule) 56 3 completed (normal schedule)....
The above interpretation applies to Davis-Besse. For plants that have adopted i
the improved Standard Technical Specifications (iSTS), SR 3.0.2 (which provides for a 25 percent extension similar to Davis-Besse TS 4.0.2) specifically refers to the frequency which, due to the changed definition of staggered testing in iSTS, is the subinterval. Therefore, the above interpretation does not apply to plants that have adopted the iSTS.
Please contact Allen Hansen of my staff at 301-415-1390 if you have any questions.
Sincerely,
%=-
V S Richard P. Savio, Acting Project Director Project Directorate III-3 Division of Reactor Projects III/IV Dffice of Nuclear Reactor Regulation Docket No. 50-346'
Enclosure:
As stated I
cc: Sea next page
y John K. Wood Davis-Besse Nuclear Power Station, Unit 1 Toledo Edison Company cc:
Mary E. O'Reilly Robert E. Owen, Chief Centerior Energy Corporation Bureau of Radiological Health 300 Madison Avenue Service Toledo, OH 43652 Ohio Department of Health P.O. Box 118 James L Freets Columbus, OH 43266-0118 Manager-Regulatory Affairs i
Toledo Edison Company James R. Williass, Chief of Staff Davis-Besse Nuclear Power Station Ohio Emergerai Management Agency 5501 North State - Route 2 2855 West Dublin Granville Road Oak Hart >or, OH 43449-9760 Columbus, OH 43235-2206 Gerald Chamoff, Esq.
Donna Owens, Dire.ctor Shaw, Pittman, Potts Ohio Department of Commerce and Trowbridge Division of Industrial Compliance 2300 N Street, NW.
Bureau of Operations & Maintenance Washington, DC 20037 6606 Tussing Road P.O. Box 4009 Regional Administrator Reynoldsburg, OH 43068-9009 U.S. Nuclear Regulatory Commission 801 Warrenville Road Ohio Environmental Protection Agency Lisle, IL 60523-4351 DERR-Compliance Unit ATTN: Zack A. Clayton Robert B. Borsum P.O. Box 1049 Babcock & Wilcox Columbus, OH 43266-0149 Nuclear Power Generation Division 1700 Rockville Pike, Suite 525 State of Ohio Rockville, MD 20852 Public Utilities Commission 180 East Broad Street Resident inspector Columbus, OH 43266-0573 U.S. Nuclear Regulatory Commission 5503 North State Route 2 Attomey General Oak Harbor, OH 43449 Department of Attomey 30 East Broad Street l
James H. Lash, Plant Manager Columbus, OH 43216 Toledo Edison Company Davis-Besse Nuclear Power Station President, Board of County 5501 North State Route 2 Commissioner of Ottawa County Oak Harbor, OH 43449-9760 Port Clinton, OH 43252 l
i Roy P. Lessy, Jr.
Akin, Gump, Srauss, Hauer & Feld, LLP 1333 New Hampshire Ave., NW., Ste. 400 Washington, DC 20036
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- CENTERCOR ENERGY j
5501 N State Rose 2 419-249 2300 John K. Wood Ook Hamo'.OH 43449 fax 41D-3218337 Vce P'eleeru Ns. tear o.
sen.
License Number NPF-3 Serial Number 2495 Docket Number 50-346 j
November 3, 1997 United States Nuclear Regulatory Commission Document Control Desk Washington, D. C. 20555-0001
Subject:
Request for Interpretation of Schedule Requirements Regarding Technical Specification Surveillance Tests Conducted on a Staggered Test Basis Ladies and Gentlemeni The purpose of this letter is to request an NRC interpretation of schedule requirements regarding Technical Specification surveillance tests conducted on a " Staggered Test Basis" for the Davis-Besse Nuclear Power Station (DBNPS), Unit Number 1 Operating License Number NPF-3. The details of this request are provided in the Enclosure. A response is requested by June 1,1998.
Should you have any questions or require additional information, please contact Mr. James L. Freels, Manager - Regulatory Affairs, at (419) 321-8466.
Very truly yours,
.4 w-MMJlaj i.
Enclosure cc:
A. B. Beach, Regional Administrator, NRC Region III S. J. Campbell, DB-1 NRC Senior Resident Inspector A. G. Hansen, DB-1 NRC/NRR Project Manager Utility Radiological Safety Board IElmlimumnuanos, hclosure
-9711070102 471103_ADOCK05000344]fp.
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U Docket Number 50-346 License Number NPF-3 Serial Number 2495 Enclosure Page1 Request for Interpretation of Schedule Requirements Regarding Technical Specification Surveillance Tests Conducted on a Staggered Test Basis
Background:
The Davis-Besse Nuclear Power Station (DBNPS) Technical Specifications (TS) Definition 1.21 states as follows:
A STAGGERED TEST BASIS shall consist of:
a.
A test schedule for n systems, subsystems, trains or designated components obtained by dividing the specified test interval into n equal subintervals, b.
The testing of one system, subsystem, train or designated components at the beginning of each subinterval.
There are no TS Bases associated with the Definitions Section of TS, however, the ir$ tent of performing testing on a staggered basis is to limit the length of time that a common cause system failure could go undetected.
Section 4.0.2 of the DBNPS TS states as follows:
Each Surveillance Requirement shall be performed within the specified time interval with a maximum allowable extension not to exceed 25 percent of the specified surveillance intervat The associated Bases for DBNPS TS Section 4.0.2 states,in part:
The provisions of this specification provide allowable tolerances for performing surveillance activities beyond those srecified in the nominal surveillance interval. These tolerances are necessary to provide operational flexibility because of scheduling and j
performance considerations. The phraw "at least" associated with a surveillance frequency does not negate this allowable tolerance value and permits the performance of more frequent surveillance activities.
The allowable tolerance for performing surveillance activities is sufficiently restrictive to ensure that the reliability associated with the surveillance activity is not significantly degraded beyond that obtained from the nominal specified interval. It is not intended that
3 Docket Number 50-346 f
License Number NPF-3 Serial Number 2495 Enclosure Page 2 the allowable tolerance be used as a convenience to repeatedly schedule the performance of surveillance at the allowable tolerance limit.
Explanation ofIssue:
The issue of interpretation is how to apply the maximum allowable extension provisions of TS Section 4.0.2 to surveillance testing conducted on a STAGGERED TEST BASIS. To illustrate the issue, assume a typical four channel instrumentation functional unit, with channel function:J testing required to be performed at least once per 31 days on a STAGGERED TEST BASIS.
Using the above example, under TS Definition 1.21, the 31 day specified test interval is divided into four equal subintervals of 7.75 days, and one channel is tested at the beginning of each subinterval. As a practical matter, at the DBNPS, such a channel functional test would typically be scheduled once a week on the same day of the week, with each channel being tested every 4 weeks. In the event that the channel functional test schedule is disrupted, for whatever reason, and it becomes necessary for the provisions of Specification 4.0.2 to be applied, there are differing interpretations as to how this should be done.
One interpretation is that the 25% allowance must be applied to the subinterval time. frame.
Under this interpretation, if last week's channel functional test (for channel "x") was completed at arbitrary time "zero", then this week's channel functional test (for channel "y") must be completed no later than 125% of the 7.75 day subinterval, or by day 9.6875.
A differing interpretation is that the 25% allowance may be applied to the 31 day interval for the particular channel of interest, irrespective of the test completion history for the other channels.
Under this interpretation, the maximum allowable extension for any channel is 125% of 31 days, or 38.75 days from the last performance of the channel functional test for that same channel.
The first interpretation ensures that if the channel "y" test is completed at day 9.6875, that time will be within 125% of 31 days since the last performance of the channel "y" test, even if each test in the past month utilized the 25% allowance. This method also ensures a relatively uniform test spacing over the 31 day interval, regardless of whether the 25% allowance is used. However, l
this method is potentially overly conservative in the sense that if each of the three previous channels were completed on the normal 7 day schedule, and the need arose to use the maximum 9.6875 day allowance for channel "y", then channel "y" testing would be required to be completed within 30.6875 days ( 3 x 7 + 9.6875 days) of the last performance of the channel "y" test. Or,if each of the three previous channels were completed on a 7.75 day schedule, and the need arose to use the maximum 9.6875 day allowance for channel "y", then channel "y" testing would be required to be completed within 32.9375 days ( 3 x 7.75 + 9.6875 days) of the last performance of the channel "y" test. In either case, the current channel "y" test would be required to be completed well within the 38.75 day limit, were the extension applied to the 31 day interval, as would be allowed by the second interpretation. The end result is that, under the
o' Docket Number 50-346 License Number NPF-3 Serial Number 2495
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Enclosure Page 3 first interpretation, a channel may need to be declared inoperable and placed in a tripped i
condition earlier than under the second interpretation. This could place the plant in a less reliable configuration since under a typical 2 out of 4 actuation logic, a spurious signal in a second channel could cause inadvertent initiation of a protective action, for example a reactor trip or a Safety Features Actuation System actuation.
However, while the second interpretation potentially allows a greater time margin to perform a l
test, it does not ensure that testing is uniformly spaced. Under the above example, a series of l
channel functional tests for each of four channels could be conducted with three 7 day subintervals and one 17.75 day subinterval.
f Reauest for Intemretation:
l The DBNPS surveillance test program is presently being conducted under the more conservative l
scheduling approach of applying the 25% maximum allowable extension of TS Section 4.0.2 to l
the STAGGERED TEST BASIS subinterval. However, as described above, this approach may l
be overly conservative and could result in equipment being prematurely declared inoperable, i
potentially placing the plant in a less reliable condition.
l For this reason, the DBNPS requests a written response from the NRC on the appropriate l
application of the 25% maximum allowable extension of TS Section 4.0.2 to TS surveillance testing performed on a STAGGERED TEST BASIS.
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