ML19210E527
| ML19210E527 | |
| Person / Time | |
|---|---|
| Site: | Haddam Neck File:Connecticut Yankee Atomic Power Co icon.png |
| Issue date: | 10/29/1979 |
| From: | Schwencer A Office of Nuclear Reactor Regulation |
| To: | Counsil W CONNECTICUT YANKEE ATOMIC POWER CO. |
| References | |
| NUDOCS 7912050167 | |
| Download: ML19210E527 (7) | |
Text
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'4 UNITED STATES yV t,
NUCLEAR REGULATORY COMMISSION
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e WASHINGTON, D. C. 20555 h
November 5,1979 Docket No. 50-213 Mr. W. G. Counsil, Vice President Nudlear Engineering and Operations Connecticut Yankee Atomic Power Company Post Office Box 270 Hartford, Connecticut 06101
Dear Mr. Counsil:
The staff has recently completed a review of the LER s and Technical Spacification requirements related to the Control Rod Position Irdication Systems (RPI) at Westinghouse PWRs. We have determined that a wide varia-tion exists in the number of LERS received and the technical specification requirements and have, therefore, decided to clarify our requirements.
At the time of development of the Standard Technical Specifications, a systematic attempt was made to clarify potentially anbiguous specifications.
One such specification was the control rod misalignment specification for Westinghouse-designed reactors. Westinghouse has performed safety analyses for control rod misalignment up to 15 inches or 24 steps (one step equals 5/8 inch).
Since anal!;is of misalignments in excess of this amount have not been submitted, we have imposed an LC0 restricting continued operation with"a misalignment in excess of 15 inches. Because the analog control rod position indication system has an uncertainty of 7.5 inches (12 steps), when an indicated deviation of 12 steps exists, the actual misalignment may be 15 inches. This is because one of the coils, spaced at 3.75 inches, may be failed without the operator knowing about it. The Standard Technical Specifications were written to eliminate any confusion about this, and allow a deviation of up to 12 indicated steps.
Surveillance requirements, on the indication accuracy of 12 steps were also prepared to ensure that the 15 inch LC0 is met.
Thee is no difference intended in requirements issued for any Westinghouse reactor. Westinghouse has informed the NRC that all of their customers have been informed of this and that all the licensees should be following the same procedures regardless of the language of their Technical Specification.
That is, plants with Technical Specifications written in terms of 15 inch misalign-nent should be considering the 12 step instrument inaccuracy when monitoring rod position.
A related problem is that the installed analog control rod position indicating system equipment may not, in some areas, be adequate to maintain the control rod misalignment specification requirement because of drift problems in the calibration curves. This is evidenced by numerous LER's concerning rod position indication accuracy.
In these cases, the uncertainty may be more than 12 steps.
1498 216 oso /67 f
me
3 Mr. W. G. Counsil November 5, 1979 The present Westinghous'e Standard Technical Specifications (Tindicated positi W-STS) require all full length control rods to be positioned within + 12 steps of their group step counter demand position. Since numeroJs problems have developed in signal conditioning circuits for display indication of control rod position, the staff has determined that the " indicated position" requirement may be fulf1!!ed by voltage measurements obtained from the position indication mechanism (and therefore no LER nced be submitted) provided a sufficient data base has been established to ensure a correlation between voltage and position.
A copy of the current, applicable W-STS Specifications (3/4.1.3.1 and 3/4.1.3.2) are attached for your information and consideration.
It is requested that you review your present technical specifications to ensure that the control rods are required to be maintained within + 12 steps indicated and that the rod position indication system is verified to be accurate to within 12 steps.
If your review indicates that this is not the case, you should so inform the Cormiission within 30 days of your receipt of this letter together with your plans to correct the deficiencies.
Any needed corrective actions may take several forms; such as (1) revising your technical specifications to limit control rod misalignment to no more than + 12 steps indicated position, (2) seeking relief by performing analyses justi7ying (with penalties if needed) greater misalignments, or (3) proposing alternate or supplemental monitoring specifications to demonstrate compliance wii.h the + 12 step indicated alignment requirement.
If yp have any questions on this matter, please contact us.
Sincerely, M
M Dennis L. Ziemann, hief Operating Reactors Branch #2 Division of Operating Remors
Enclosure:
W-STS Specifications 3/4.1.3.1 and 3/4.1.3.2 1498 217
Mr. W. G. Counsil November 5,1979 cc w Day,/ enclosure: Berry & Howard Counselors at Law One Constitution Plaza Hartford, Connecticut 06103 Superintendent Haddam Neck Plant RFD #1 Post Office Box 127E East Hampton, Connecticut 06424 Mr. James R. Himmelwright
-Northeast Utilities Service Company P. O. Box 270 Hartford, Connecticut 06101 Russell Library 119 Broad Street Middletown, Connecticut 06457 8
1498 218
REACTIVITY CONTROL SYSTEMS 3/4.1.3 MOVABLE. CONTROL ASSEMBLIES GR,0UP HEIGHT LIMITING CONDITION FOR OPERATION 3.1.3.1 All full length (shutdown and control) rods, and all part length rods which are inserted in' the core, shall be OPERABLE and positioned within 212 steps (indicated position) of their group step counter demand position.
APPLICABILITY:
MODES la and 2*
ACTION:
a.
With one or more full length rods inoperable due to being immovable as a result of excessive friction or mechanical interference or known to be untrippable, determine that the SHUTDOWN MARGIN require-ment of Specification 3.1.1.1 is satisfied within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
b.
With more than one full or part length rod inoperable or misaligned from the group step counter cemand position by more than i 12 steps (indicated position), be in HOT STANDBY within 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.
c.
With one full or part length rod inoperable due to ccJses other than addressed by ACTION a, above, or misaligned from its group step counter demand height by more than 2 12 steps (indicated position),
POWER OPERATION may continue provided that within one hour either:
1.
The rod is restored to OPERABLE status within the above alignment requirements, or 2.
The rod is declared inoperable and the SHUTDOWN MARGIN requirement of Specification 3.1.1.1 is satisfied.
POWER OPERATION may then continue provided that:
a)
A reevaluation of each accident analysis of Table 3.1-1 is performed within 5 days, thi~ reevaluation shall confirm that the previously analyze 6 results of these accidents remain valid for the duration r? operation under these conditions.
b)
The SHUTDOWN MARGIN requirement of Specification 3.1.1.1 is determined at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.
- See Special Test Exceptions 3.10.2 anc 3.10.3.
1498 219 t-STS 3/4 1-14 007 I gg
REACTIVITY CONTROL SYSTEMS LIMITING CONDITION FOR OPERATION (Continued) c)
Apowerdistributionmapisobtafnedfromthemovable within their limits wikhin 72 hobYs.re verified to be incore detectors and F (Z) and F a
d)
{ither the THERMAL POWER level is reduced to less than or equal to 75% of RATED THERMAL POWER within one hour and within the.next 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> the high neutron flux trip setpoint is reduced to less than or equal to 85% of RATED THERMAL POWER, or e)
The remainder of the rods in the group with the inoperable rod are aligned to within : 12 steps of the inoperable rod w'*.hin one hour while maintaining the rod sequence and
' tion limits of Figures (3.1-1) and (3.1-2); the THt fMAL POWER level shall be restricted pursuant to Speci-fication (3. l.3.6) during subsequent operation.
SURVEILLANCE REOUIREMENTS 4 l.3.1.1 The posit. ion of each full and part length rod shall be determined tto be within the group demand limit by verifying tne individual rod positions at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> except during time intervals when the Rod Position Deviation Monitor is inoperable, then veri"" the group positions at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
4.1.3.1.2 Each full length rod not fully inserted and each part length rod which is inserted in the core shall be determined to be OPERABLE by movement of at least 10 steps in any one direction at least once per 31 days.
-w-STS 3/4 1-15 M4R 15 EU7 1498 220
TABLE 3.1-1 ACC'IDENT ANALYSES REOUIRING REEVALUATION IN THE EVENT OF AN INOPERABLE FULL OR PART LENGTH R00 Ro.d Cluster Control Assembly Insertion Characteristics
. Rod Cluster Control Assembly Misalignment Loss Of Reactor Coolant From Small Ruptured Pipes Or From Cracks In larg: Pipes Which Actuates The Eme.rgency Core Cooling System Single Rod Cluster Control Assembly Withdrawal At Full Power Major Reactor Coolant System Pipe Ruptures (Loss Of Coclant Accioent)
Major Secondary System Pipe Rupture Rupture of a Co'r. -ci Rod Drive Mechanism Housing (Rod Cluster Control Asser.cly Eje: tic.')
t g-ST5 3/4 1-16 OCT I 1976 1498 221
b REACTIVITY CONTROL SYSTEMS POSITION INDICATION SYSTEMS-OPERATING LIMITING CONDITION FOR OPERATION 3.1.3.2 The shutdown, control and part length control rod position. indication system and the demand position indication system shall be OPERABLE and capable of determining the control rod positions within c 12 steps.
APPLICABILITY:
MODES 1 and 2.
ACTION:
a.
With.a maximum of one rod position indicator per bank inoperable either:
1.
Determine the position of the non-indicating rod (s) indirectly by the movable incore detectors at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and immediately after any motion of tne non-1.ndicating rod which exceeds 24 steps in one direction since the last determination of the rod's position, or 2.
Reduce THERMAL POWER TO less than 50% of RATED THERMAL POWER within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, b.
With a maximum of one demand position indicator per bank inoperable either:
1.
Verify that all rod position indicators for the affected bank are OPERABLE and that the most withdrawn rod and the least withdrawn rod of the bank are within a maximum of 12' steps of each other at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, or 2.
Reduce THERMAL POWER to less than 50% of RATED THERMAL POWER within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.
SURVEILLANCE REQUIREMENTS 4.1.3.2 Each rod position indicator shall be determined to be OPERABLE by verifying t; at the demand position indication system and the rod position indication system agree within 12 steps at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> except during time intervals when the Rod Position Deviation Monitor is inoperable, then compare the demand position indication system and the rod position indica-tion system at least once per 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.
1498 222 JUL 151979 W-ST5 3/4 1-17
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