ML20247C773
| ML20247C773 | |
| Person / Time | |
|---|---|
| Site: | Calvert Cliffs  |
| Issue date: | 08/31/1989 |
| From: | Creel G BALTIMORE GAS & ELECTRIC CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737 NUDOCS 8909140104 | |
| Download: ML20247C773 (6) | |
Text
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n BALTIMORE l
GAS AND.
I
~
ELECTRIC CHARLES CENTER R O. BOX 1475. BALTIMORE, MARYLAND 21203 GEORGE C. CREEL vice pareiorwr Nuctran Eutner
. (aoil aso-dese s.-
I August 31, 1989 q
U. S. Nuclear Regulatory Commission
- Washington, DC 20555 l
ATTENTION:
Document Control Desk j
SUBJECT:
Calvert Cliffs Nuclear Power Plant Unit Nos.1 & 2; Docket Nos. 50-317 & 50-318 1
Response to Request for Additional Information Regarding Reactor '
-l Vessel Level Monitorine System j
REFERENCES:
' (a) CE Owners ~ Group Letter from Mr.
R.
W.
Wells (CEOG) to i
Mr. H. L. Thompson (NRC), RWN-87-12, dated February 19, 1985,
'l
" Technical Specification - for the Reactor Vessel Level Monitoring Systems" 1
(b) Letter from Mr.
D. M. Crutchfield (NRC) to Mr.
R.
W.
Wells (CEOG), dated October 28, 1986, Generic Reactor Vessel Level I
Monitoring Systems Technical. Specification Safety Evaluation 1
- Report l
(c) Letter from Mr. J. A. Tiernan (BG&E) to NRC Document Control Desk, dated July 10, 1987, Request for Reactor Vessel Level MonitoringSystems Amendment (d) Letter from Mr. S. A. McNeil (NRC) to Mr. G. C. Creel (BG&E),
dated August 3,1989, Request for Additional Information Gentlemen:
In Reference (d), you requested we provide additional information regarding our request for a Technical Specification change (Reference c) regarding.our Reactor Vessel Level l
Monitoring System (RVLMS). Our response to your request is contained in Enclosure 1.
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i 8909140104 890831
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PDR ADOCK 05000317 P
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Document Control Desk August 31, 1989 Page 2 Should you have any further questions regarding this matter, we will be pleased to discuss them with you.
Very truly yours,
/
/
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ijd GCC/MDM/ dim Enclosure I
cc:
D. A. Brune, Esquire J. E.
Silberg, Esquire R. A.Capra, NRC S. A.McNeil,NRC W. T. Russell, NRC V. L. Pritchett, NRC T. Magette, DNR f',
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4 ENCLOSURE I REPLY TO REQUEST FOR ADDITIONAL INFORMATION; RVLMS TECHNICAL SPECIFICATION AMENDMENT Introduction In response to NUREG-0737, Post TMI Requirements, a Reactor Vessel Level Monitoring System (RVLMS) was installed on both Calvert Cliffs' Units. The RVLMS, along with existing instrumentation (e.g.,
pressurizer
- level, subcooling, Th, Tc, core exit thermocouple), is used to provide core and reactor coolant system voiding indications.
RVLM5 was not designed to be the sole means of indicating core and coolant voiding.
Our amendment request was based on the generic Technical Specification submitted by the Combustion Engineering Owners Group (CEOG) (Reference a). The CEOG submittal was approved by the NRC (Reference b).
The loss of one or both channels is discussed in the safety evaluation report. If both channels of RVLMS become inoperable, additional instrumentation, as discussed above, is available to detect void formation. The safety evaluation recognizes repairs may not be feasible under various conditions and allows continued operation until "the next refueling shutdown."
The most extensive type of RVLMS failure requires replacing a probe. To replace a probe, we must perform several major tasks. These tasks include:
1.
cooling and draining down the Reactor Coolant System 2.
disconnecting and/or removing reactor head instrumentation cable 3.
removing the missile shield 4.
opening the equipment hatch.
The reactor vessel head does not have to be removed to replace a probe.
During a refueling shutdown, these tasks are performed as part of the normal refueling process. Extensive planning and resources are needed to ensure a successful refueling shutdown.
BG&E defines the refueling shutdown as starting when the plant enters MODE 6 from MODE 5 and ending when changing from MODE 6 back to MODE 5.
All other modes preceding or following MODE 6 are considered cooldown, heatup, or power operation modes.
The term "next scheduled refueling," as used in our amendment request, is defined as the refueling following a heatup or power operation. Our current refueling cycle is once every 24 months. In this response we have interpreted " Prior to Refueling" to mean from the time we start down in MODE I from 100% power to the time we enter MODE 6.
" Post Refueling" is the time from exiting MODE 6 to the time we first reach 100% power after refueling.
The following information is provided in response to the questions asked in your letter (Reference d): _ _ _ _ _ _ - _ - _ _ _ _
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i55 ENCLOSURE I REPLY TO REQUEST. FOR ADDITIONAL INFORMATION; RVLMS TECHNICAL SPECIFICATION AMENDMENT Ouestion No. I If both RVLMS channels were inoperable due to RVLMS failures inside the Unit's reactor vessel, would your proposed RVLMS Technical Specifications permit the Unit's return ~ to 100%. power operation, without an operable RVLMS ~ channel, following a refueling outage, if these RVLMS channel failures were identified while in:
Response
a.
MODES 1-5 prior to refueling the Unit and MODE 6:
If the failure : was discovered while in one of the above modes, we could not return to 100% power operation. As stated in our amendment request, at least one channel will be restored to operable status. During MODE 6 it is feasible to replace a probe. Repairs cannot be made to inoperable probes within the vessel, only replacement of the probe.
b.
MODE 5, 4, 3, 2, I (all post-refueling):
If the failure was discovered during one of the above modes, we could return to 100% power. Replacement of a probe is not feasible during
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these modes. The hardships were discussed in the introduction.
Sufficient redundant instrumentation used to monitor void indications is available if both channels of RVLMS became inoperable during one of these modes.
Question No. 2 If both RVLMS channels were inoperable due to failures inside containment but outside the reactor vessel, ' would your proposed RVLMS Technical Specification permit the Unit's return to 100% power operation, without an operable RVLMS channel, following a refueling outage, if these RVLMS channel failures were identified while in:
Response
a.
MODES 1-5 prior to refueling the Unit and MODE 6:
If the failure was discovered during one of the above modes, we could 1121 return to 100 % power operation. As stated in our amendment request, at least one channel will be restored to operable status, c,
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m 4 ENCLOSURE 1-
'N*
REPLY TO REQUEST FOR ADDITIONAL INFORMATION; RVLMS TECliNICAL ' SPECIFICATION AMENDMENT b.
MODE 5, 4. 3, 2, I (all post-refueling):
If the failure was discovered during one of the above modes, we could l
return to 100% power. Conditions may arise where containment entries i
are not advisable (ALARA) or spare parts are not available.
l Sufficient redundant instrumentation used to monitor void indications l
is available if both channels of RVLMS became inoperable during one of these modes.
All attempts will be made to repair at least one channel. If repairs are not feasible, the Units can be operated until the next refueling shutdown as long as alternate methods of void detection are initiated.
Ouestion No. 3 If both RVLMS channels were inoperable due to failures outside containment, would your proposcd RVLMS Technical Specification permit the Unit's return to 100% power operation, without an operable RVLMS channel, following a refueling outage, if the.Se RVLMS channel failures were identified while in:
Response
a.
MODES 1-5 prior to refueling the Unit and MODE 6:
If the failure was discovered during one of the above modes, we could noi return to 100% power operation. As stated in our amendment request, at least one channel will be restored to operable status.
b.
MODE 5, 4,
.3, 2, I (all post-refueling):
If the failure was discovered during one of the above modes, we could return to 100% power. All attempts will be made to repair at least one channel as soon as possible. If repairs are not feasible, the Units can be operated until the next refueling shutdown as long as alternate methods of void detection are initiated.
Sufficient redundant instrumentation used to monitor void indications is available if both channels of RVLMS became inoperable during one of these modes.
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lc ENCLOSURE-1
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7.,--..-
REPLY TO REQUEST-FOR ADDITIONAL INFORMATION; j
RVLMS TECHNICAL SPECIFICATION AMENDMENT Qgestion No. 4 Please describe the method you shall use to calibrate the RVLMS sensors (HJTCs) during - the Unit's mid-cycle surveillance / maintenance outage.
There was an error in our amendment request. The calibration frequency for-RVLMS should state N/A instead of 18 months. The RVLMS sensors. cannot be-calibrated. A channel check. is the only surveillance performed on RVLMS.
Conclusior.
In conclusion, we feel the words in our current submittal are consistent with the CEOG submittal and its ' N R C Safety Evaluation Report. - Under all conditions, every effort will be made to repair inoperable RVLMS channels when repairs are feasible.
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