ML20235L145
| ML20235L145 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 02/02/1989 |
| From: | Frizzle C Maine Yankee |
| To: | NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM) |
| References | |
| RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.2, TASK-TM CDF-89-16, GL-88-17, MN-89-10, NUDOCS 8902270385 | |
| Download: ML20235L145 (8) | |
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MaineYankee hlABLE ELECTRICITY FOR MAINE SINCE 197{
EDISON DRIVE. AUGUSTA, MAINE 04330. (207) 622 4868 g
February 2, 1989 MN-89-10 CDF-89-16 UNITED STATES NUCLEAR REGULATORY COMMISSION A
ntion:
Document Control Desk Washington, D. C.
20555
References:
(a)
License No. DPR-36 (Docket No. 50-309)
(b) USNRC Generic Letter 88-17:
Loss of Decay Heat Removal dated November 17-, 1988
Subject:
Response to Generic Letter 88-17 Gentlemen:
Please find enclosed Maine Yankee's response to the six programmed enhancements recommended in the subject Generic Letter.
Please contact us if you have any questions.
Very truly yours, MAINE YANKEE l/
ih 4
th Charles D. Frizzle President
.CDF:BJP Attachment c: Mr. Richard H. Wess-en Mr. William T. Russell Mr. Cornelius F. Holden Mr. Patrick M.
Sears Mr. Clough Toppan STATE OF MAINE Then personally appeared before me, Charles D. Frizzle, who being duly sworn did state that he is President of Maine Yankee Atomic Power Company, that he is duly authorized to execute and file the foregoing response in the name and on behalf of Maine Yankee Atomic Power Company, and that the statements therein are true to the best of his knowledge p p ef.
8902270385 890202 PDR ADOCK 05000309 P
PDC Notary Public f
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MaineYankec-MAINE YANKEE RESPONSE TO GENERIC LETTER 88-17
'SIX PROGRAMMED ENHANCEMENTS PROGRAMMED ENHANCEMENT NO. 1 - INSTRUMENTATION-Provide reliable indication of parameters that' describe the state of the RCS and the performance-of' systems normally used to cool the RCS for both normal and accident conditions. At a minimum, provide the following in the CR:
a.
two independent RCS level indications L
b.
at least two independent temperature measurements representative of the core exit whenever the RV head is located on top of the RV (He r
suggest that temperature indications be provided at all times.)
c.
the capability of continuously monitoring DHR system performance whenever a DHR system is being used for cooling the RCS i
d.
visible and -audible indications of abnormal conditions in temperature, level, and DHR system performance
' MAINE YANKEE RESPONSE a.
The Maine Yankee Primary Inventory Trend System (PITS) was installed l
to provide reactor vessel level information for the inadequate core cooling instrumentation (ICCI) system.
These systems were designed and installed in compliance with the requirements of Item II.F.2 of NUREG-0737.
The PITS system will be modified during the 1990 refueling outage to l
provide RCS level indication whenever reactor vessel (RV1 water level
(
is lower than three feet below the RV flange, thereby providing two l
independent RCS level indications in the Control Room.
b.
Procedures currently in effect require at least two independent temperature measurement instruments whenever the RCS is at reduced inventory.
It has been the practice, at Maine Yankee, to maintain at least two core exit thermocouple operational until after the cavity has been flooded for the removal of the upper guide structure, at the beginning of a refueling, and to re-establish at least two core exit thermocouple operational prior to commencement of cavity draining at l
the end of the refueling.
These practices, however, have not been required by procedures.
The applicable procedures will, by June 1,1989, be revised to require that at least two independent temperature measurements, representative of the core exit, be operable whenever there is less than 23 feet of water above the core.
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.The capability to continuously monitor the performance-of the.
Residual Heat Removal System is adequately provided for by utilizing both Main Control Board instrumentation and locally installed instrumentation.
The MCB-instrumentation includes:
Level Indications 1 Reactor Vessel Hide Range Reactor Vessel Narrow Range Two-Channel Primary Inventory Trend System Flow Indications:
Individual Loop Flow Indicators.(one:for each loon)
Total RHR Flow Indicator (1).
RHR Pump Ammeters (on front of MCB, one for each pump)
Pressure Indicators:
RHR/LPSI-Header Pressure (1)
Temperature Indicators:
RHR Heat Exchanger Inlet Temperature (1)
RHR Heat Exchanger Outlet Temperature (1)
Core Exit Thermocouple Miscellaneous Indicators:
RHR Pump Auto Trip Light Indication RHR Pump Suction Valve Position Light ~ Indicators Remote Operated System Valve Position Light Indicators Mditional locally installed system instrumentation includes:
~RHR/LPSI Header Pressure Indicator RHR Pump Suction Pressure Indicator RHR Pump Discharge Pressure Indicators Capability to Install Tygon Level Indicator Capability to Install Heise Gauge Level Indicator (Head of Water Measurement) d.
Adequate indications of abnormal conditions in temperature, level and RHR system performance is provided by visible and audible indications as outlined below. Since some alarms rely on the plant computer, applicable logs will be revised to require increased log taking frequency if the computer is out of service.
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. t PAtameter Visible
' Audible (Alarm)'
' Level Yes'
.Yes' Flow.
Yes' Yes*
Pressure Yes-
'No
. Temperature Yes Yes*
RHR Pump Trip
~Yes Yes-
' Auto Closure of Yes Yes
'RHR/RCS' System Isolation Valves Pump Amps Yes No
- Alarms rely on computer being operable and require increased log taking frequency when'the computer is out of service.
ENHANCEMENT NO. 2 - PROCEDURES:
Develop and implement procedures that cover reduced inventory operation and that provide an adequate basis for entry into a reduced inventory condition. These include:
a.
Procedures that cover normal operation of the NSSS, the containment, l
and supporting systems under conditions for which cooling would p
normally be provided by DHR systems, b.
Procedures that cover emergency, abnormal, off-normal, or the equivalent operation of the NSS5, the containment, and supporting systems-if an off-normal condition occurs while operating under conditions for which cooling would normally be provided by DHR systems.
c.
Administrative controls that support and supplement the procedures in item.; (a), (b), and all other actions identified in this communication, as appropriate.
MAINE YANKEE RESPONSE:
a.
Procedures have been developed and implemented that cover normal operations of the NSSS, containment and supporting systems under conditions for which cooling would normally be provided by the RHR system.
These procedures include:
Plant Cooldown Operations at Cold Shutdown Reactor Coolant System Fill and Vent RHR System Start-up and Operation RHR System Shutdown RHR Slipstream Purification via the Letdown Purification Train RHR Slipstream Purification via the Spent Fuel Pool Purification Train 0967L-SDE
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Mainej(ankee s
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k Degasification'of the RCS via RHR Slipstream Cavity Flooding Refueling Cavity. Purification.
Refueling Cavity Draining.
-Lowering of the Reactor Vessel Level to One Foot Balow the. Flange
.(Elevation 19')-for Head Removal p
p
. Lowering of theLReactor Vessel Level from Elevation 19 to-F Elevation 15' for Maintenance Work b.
Procedures have been developed and implemented that cover emergency, abnormal, off-normal, or' the equivalent operation of the NSSS, the containment, and supporting systems if an off-normal condition occurs while operating.under conditions for which cooling would normally be provided by the RHR system. These procedures include:
Loss of Decay Heat Removal Capability While Shutdown
' Loss of RHR During a Plant Cooldown Loss of.RHR in a Reduced Inventory Condition (RCS level Lowered to less Than 19')
' Loss of RHR During Refueling (cavity flooded)
Loss of RHR During a Plant Heat-up Loss of.RHR Heat Sink or Support Systems Loss of RCS Inventory Abnormal Loss of Pefueling Cavity Level Mitigation of Air Binding of the RHR System Refueling' Accidents Loss.of off-site Power While Shutdown c.
Administrative Controls have been established that support and supplement the procedures in items (a) and (b) above as appropriate.
These administrative controls include but are not limited to the-following:
Administrative procedures that ensure timely review and approval of the above procedures that outline guidance on such issues as:
Crew Briefings Procedure Implementation and Compliance E0P/A0P Adherence System Restoration Log Keeping Technical Specification Adherence Night Orders I
Temporary Procedures Procedure Change Requests (Normal Operating Procedures ONLY)
PROGRAMMED ENHANCEMENT NO. 3 - E0VIPMENT a.
Assure that adequate operating, operable, and/or available equipment of high reliability is provided for cooling the RCS and for avoiding a j
loss of RCS cooling.
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b.
Maintain sufficient existing equipment in an operable or available status so as to mitigate loss of_ DHR or loss of RCS: inventory should
~they occur.- This should include' at least one high pressure injection pump'and one other system. The water addition rate capable of being
- provided by each' equipment item should be at least sufficient to keep' the core covered.
c.
Provide adequate equipment for personnel communications that involve activities related to the RCS or systems necessary to maintain the RCS' in a stable and controlled condition.
MAINE YANKEE RESPONSE:
a.
Technical Specifications require that whenever there is fuel in the reactor, at least one core cooling mechanism shall be in operation and a second mechanism operable. When the plant is in the condition whereby the'only cooling mechanisms capable of providing core cooling are the RHR systems, administrative controls have been put in place to ensure the availability of these systems. OP procedure 1-7-2, Operations at Cold Shutdown, provides for a check to ensure that these operational.and availability requirements are continuously met.
b.
Current Abnormal Operating Procedures address both loss of RHR and loss of RCS inventory should they occur.
The methods provided in the procedures to restore RCS inventory range from gravity feed from the RHST to makeup with a HPSI pump depending upon plant conditions at the time.
The' procedures,.however, are not specific as to maintaining equipment available in regards to addition rate capability since analysis to determine this capability has not been done.
Procedures will be revised providing this specific guidance pending the completion of the analysis.
c.
Adequate equipment is available for personnel communications'that involve activities related to the RCS or systems necessary to maintain the RCS in a stable and controlled condition.
This equipment includes:
Installed Plant Intercom System (Femco)
Installed Sound Powered Communications System Portable Hireless Telephone System Headsets Plant Radio Communication System The various systems are available and utilized on a case specific basis under the guidelines of Operating Procedure 1-300-6, Operational Communications.
EROGRAMMED ENHANEMENT NO. 4 - ANALYSES:
Conduct aralyses to supplement existing information and develop a basis for procrdures, instrumentation insta11atics and response, and equipmert/NSSS interactions and response. lhe analyses should encompass thermodynamic and physical (configuration) states to which the hardware can be subjected and should provide sufficient depth that the basis is developed.
Emphasis should be placed upon obtaining a complete understanding of NSSS behavior under nonpower operation.
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MaineYankee
' MAINE YANKEE RESPONSE:
Maine Yankee plans to participate in the CE Owner's Group (CE0G)
. analyses pertaining to the RHR system.
He also plan to perform plant-specific analyses to address, for example, plant conditions leading to the loss of RHR and appropriate plant responses (e.g.,
vortexing,~ time to boil and core recovery, adequate vent size to preclude pressurization). Analyses will also address the rate of j
additional inventory makeup capability available from other systems i
if RHR becomes inoperable.
This work should be completed before the
.1990'refteling outage.
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1 PROGRAMMED ENHANCEMENT NO. 5 - TECHNICAL SPECIFICALLQNS1 l
N Technical Specifications (TSs) that restrict or limit the' safety benefit of the actions identified in this letter should be identified and appropriate changes should be submitted.
MAINE YANKEE RESPONSE:
J t
A review of the current Technical Specifications has not revealed any specifications that would restrict or limit the safety benefit of the planned improvements.
Results of plant-specific analyses to be performed to address the Programmed Enhancement No. 4 will be examined to ensure that any identified administrative improvements that could enhance' safety are not constrained by Technical Specifications.
PROGRAMMED ENHANCEMENT NO. 6 - RCS PERTURBATIONS:
Item (5) of the expeditious actions should be reexamined and operations refined as necessary to reasonably minimize the likelihood of loss of DHR.
MAINE YANKEE RESPONSE:
I Item (5) of the expeditious actions shall be reexamined and operations refined as necessary to reasonably minimize the likelihood of loss of DHR.
This reexamination will include the following:
Identification, based upon industry events, of activities shown to have a potential impact upon RHR system operation.
Identification of activities that could perturb RCS inventory or lead to a loss of RHR given a single malfunction.
Consideration of any temporary instrumentation and its potential use or misuse to contribute to any impact upon RHR system operation.
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-Following the completion of this reexamination, procedures that require operation at reduced inventory will be revised to prohibit those activities identified above or provide specific guidance to accommodate such activities if they are unavoidable.
In addition, i
specific guidance will be provided regarding the installation, use and maintenance of temporary instrumentation with specific instructions to avoid it altogether, if at all possible.
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