ML20011E122
| ML20011E122 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/26/1990 |
| From: | Hukill H GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| C311-89-2115, GL-89-13, NUDOCS 9002080038 | |
| Download: ML20011E122 (8) | |
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Writer's Direct Dial Number:
January 26,;1990 C311-89-2115 1
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.U.S. Nuclear Regulatory Comission s
Attention: Document Control Desk 9.
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- Washington, D.C. 320555' h
. Gentlemen:)
Three Mile' Island Nuclear Station, Unit 1 (TMI-1) 1 s
Operating License No'. DPR-5
. Docket No. 50-289
. Generic-Letter 89-13 Service Water System Problems Affecting n
' Safety-Related Equipment j
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~ Attached is'GPU Nuclear's response to Generic Letter-(GL) 89-13.concerning the.
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-TMI-1 Service Water Systems. The attachment summarizes the recommended actions L
- of the GL and provides'GPU' Nuclear's response to each action.
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ATTACHMENT 1 C311-89-2115 Recommended Action 1 to GL*89-13 "For open-cycle-service water systems, implement and maintain an-ongoing program of surveillance and control techniques to significantly reduce the
' incidence of flow blockage probisms as a result of biofouling."
GpU Nuclear Response-
{The open-cycle service water systems per the criteria of GL 89-13 for TMI-1
- are
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Decay Heat River Water (DR)
Nuclear Services River Water (NR)
Reactor Building Emergency Cooling Water Systems (RR)
Screen House Ventilation Cooling Water System (SW) (Items A-D) to GL 89-13 provides a recommended program for responding to Recommended Action 1.
The following describes GPU Nuclear's program in response to the recommended actions described in Enclosure 1 to GL 89-13., Item A' GPU Nuclear currently performs an annual sampling of the TMI Intake Structures for-biological fouling organisms. Additionally, TMI-1 Technical
' Specification Table 4.1-2, " Minimum Equipment Test Frequency," requires a visual inspection of silt accumulation of,the Intake Pump House Floor each refueling period.
Furthermore, this table requires a quarterly silt _
' accumulation measurement of. the pump house floor.
Intake bays for the service water systems are inspected by scuba divers during the desilting process for silt depth.
Samples are inspected by Environmental Controls for Asiatic Clams.
'* Enclosure 1, Item B The service water systems at TMI-1 are treated periodically, as necessary to -
prevent biofouling (e.g., chlorine). The frequency and duration of this biocidsl-treatment program may'be adjusted based on ambient river conditions and experience (e.g., results of internal component inspections, effluent chlorine concentration).
In the summer of 1989 Asiatic clams were initially found-~in the TMI Intake Structure.
Biocidal treatment prior to this period was not specifically directed toward clam control. The current biofouling control practice is to chlorinate the service water system three times per day at the rate consistent with the site's NPDES permit. Biocidal treatment is.not conducted during periods of low river water temperature (e.g., mid November to mid April). Additionally, GPU Nuclear is conducting a testing I '
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- _ Enclosure 1, Item B'(Cont'd.)
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l (program on the'TMI-1 Circulation WaterLSystem to determine the effectiveness J
of an alternats biocidal-treatment.- The results of this testing program.
will be evaluated for applicability to the service water systems, subject-to Federal,. State and Local environmental regulations, f
4 Enclosure 1 Item C H
This item states " redundant and infrequently used cooling loops should be j
flushed and flow tested periodically at the maximum design flow to ensure that they are not fouled or clogged".
In response.to the above,-three (3) of the open cycle. systems (i.e., DR, RR, and SW) are' redundant. However, only the OR and RR systems are infrequently used. The ')R system is flushed and flow cested at design flow on a quarterly basis.; The RR system is flushed and flow tested at design flow 1
during each refueling outage.
Furthermore, the river water pumps are operated at least quarterly.
Operating these pumps ensures that stagnant pump suction lines are not blocked and consequently limits the cpportunity for undisturbed clam colonization and growth.
Flushing of the cooling coils is not specifically done for the'SW system.
R Normally.one ventilation cooler is in service during plant operation and the other is in standby. The standby train of the SW system is infrequently used-and is flushed periodically. Specifically, the SW system is flow tested on a quarterly basis. To demonstrate flow and provide flushing of the SW ' coils, valves will be positioned to allow cooling water flow through
.the heat exchanger as part of the quarterly flow test.
- -Enclosure 1, Item D This item states that " samples of water:and substrate should be collected annua 11y'to. determine if-Asiatic clams have populated the water source.
Water and substrate sampling is only necessary at freshwater plants that have not previously detected the presence of Asiatic Clams in their source L
water bodies.
If Asiatic Clams are detected, utilities may discontinue this sampling activity if desired, and the chlorination (or equally effective) treatment program should be modified to be in agreement with paragraph B 1
above."
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GPU Nuclear currently conducts an annual pondwide sampling of-the York Haven Pond to monitor the presence and distribution of Asiatic Clams near TMI.
GPU Nuclear letter 5211-83-2042 dated February 7, 1983, which responded to IE Bulletin 81-03, stated that GPU Nuclear would increase the surveillance
. frequency for Asiatic Clams to quarterly upon identification of their H
movement. ' Asiatic Clams were identified in the TMI intake structure in l-1989. However, GPU, Nuclear believes a quarterly surveillance' for Asiatic Clams-is no longer warranted since the presence of Asiatic Clams has been established. GPU Nuclear will continue to conduct the' annual sampling until L~
-such time that an effective ~ biocidal treatment program for Asiatic Clams is l
~ established per Enclosure 1, Item B to the Generic Letter.
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> > y Recommended-Action 11 to GL 89-13
'" Conduct a test program to verify the heat transfer capability of all safety
, related heat exchangers cooled by service water.".... The need for testing of closed-cycle system heat exchangers has not been considered necessary because T
~ f the assumed high quality of existing chemistry control programs."
o "A program acceptable to the NRC for heat exchanger. testing is describad in
' Program for Testing Heat Transfer Capability' (Enclosure 2).
It should be noted that Enclosure 2 is provided as guidance for an acceptable program. An equally effective program to ensure satisfaction.of the heat removal requirement of-the service water system would~also be acceptable."
GPU Nuclear Response Recommended Action II to GL 89-13 states "An example of an alternative action i
that would be acceptable to the NRC is frequent regular maintenance of a heat exchange'r'in lieu of testing for degraded performance of the heat exchanger."
The TMI-1 service water systen heat exchangers listed in Attachment 2 are inspected periodically in accordance with the TMI-1 Preventive Maintenance Program which requires that the heat exchangers be inspected for clam shells or other biofouling.
If shells or other biofouling are found, the TMI-1 Control Room and the Environmental Controls Department are immediately notified.
Additional information pertaining to the TMI-1 inspection program for
.open-cycle service water system heat exchangers is provided in Attachment 2.
The frequency of inspection of these heat exchangers is subject to change based on plant operating history and inspection results.
Recommended Action III to GL 89-13
" Ensure by establishing a routine inspection and maintenance program for open-cycle service water system piping and components that corrosion, erosion, protective coating failure, silting, and biofouling'cannot degrade the performance of the safety related systems supplied by service water."
GPU Nuclear Response
.As indicated in the responses to Recommended Actions I & II, procedures l
. currently exist for inspecting open-cycle service water systems for the presence of biofouling errosion, corrosion, coating condition and for removing 1
occumulations of silt. Additionally, GPU Nuclear conducts a Preventive i
Maintenance (PM) program for the piping and components of each open-cycle system which provide the assurance that the system will perform its safety related function. Thus, GPU Nuclear believes that our PM program satisfies the L
intent of this recommended action. Additionally, hydro tests are performed, in L-accordance with ASME Section XI, on the piping of the open-cycle service water j
. systems to verify the integrity of these-systems.
Recommended Action IV to GL 89-13 L
" Confirm that the service water systems will perform its intended function in accordance with the licensing bases for the plant.
Reconstitution of the design basis of'the system is not intended. This confirmation should include a review of the ability to perform required safety funci. ions in the event of u
L failure of a single active component."..
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1 GPU Nuclear Response An assessment of the operational readiness of the TMI-1 open-cycle service water systems was addressed in TMI Audit Report S-TMI-87-07 dated August 25, 1987. This audit was conducted by comparing configuration; physical condition; and operating, maintenance, and surveillance.proceduras; to the design basis of the plant including system walkdown. The results of tnis audit were that the current design, operation and maintenance of the open-cycle service water-systems are consistent with design basis documents. 'An audit of the Decay Heat Closed Cooling Water System (i.e., a closed-cycle system) was also performed to assess its operational readiness (Reference S-TMI-86-05). This audit report determined that the operation of the Decay Heat Closed Cooling Water System is_
j consistent with.the design basis documents.
A similar review will also be performed to confirm the design basis of the remaining closed-cycle service l
water system (i.e., the Nuclear Services Closed Cooling System). Additionally, a review will be performed to confirm the ability of the open-cycle and
' closed-cycle systems "to perform required safety functions in the event of a
-failure of a single-active component". These actions will be completed prior to plant startup following the 9R outage in accordance with the recommendations of GL 89-13
'Per the requirements of this GL, confirmation of the completion of these actions will be provided in a docketed submittal "within 30 days of_
such implementation."
Recommended Action'V to GL 89-13
" Confirm that maintenance practices, operating and emergency procedures, and training that involves the service water system are adequate to ensure that safety-related equipment cooled by the service water system will function as I
intended and that operators of this equipment will perform effectively. This L
confirmation should include recent (within the past 2 years) reviews of L
' practices, procedures, and training modules."
n Gpu Nuclear Response TMI-1 procedures are reviewed on a biennial basis which provides reasonable L
assurance that TMI-1 procedures are current and reflect plant configuration.
L GpVN personnel review maintenance, operating, surveillance, emergency f
procedures, etc., dealing with open and closed cycle service water systems via E
this biennial review process.
In addition.to the biennial review, other i
procedural changes are made as the result of vendor recommendations, plant l
modifications, License Amendnents, etc.
Furthermore, QA audits similar to L
those discussed-in the response to Recemmended Action IV, also serve to confirm
.the adequacy of procedures related to service water systems.
The TMI Training Department program for reviewing and maintaining lesson plans ensures that equipment and procedure changes are incorporated in lesson plans and that lesson plans are maintained current. Additional training is accomplished through on-the-job training, industrial experience, meetings, etc.
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. Thus GPU Nuclear believes that our current procedure and training program l
provides assurance that the safety-related equipment cooled by service water systems will perform their intended function and that operators of this equipment will perform effectively.
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-.i ATTACiflENT 2
., - e INSPECTION PROGRAM'FOR OPEN-CYCLE HEAT EXCHANGERS HEAT LAST PREVIOUS SYSTEM EXCHANGER INSPECTED INSPECTIONS COMMENTS Decay Heat DC-C-2A 11/09/84 09/14/82 The DR System provides river water for the Decay Heat River Water 08/24/82 Service Coolers. Both DC-C-2A and 2B will be (DR) inspected-as part of the_BR Outage commencing January 1990. The results of this inspection, plus DC-C-2B 02/28/84 08/06/82 the 'results of past inspections, will be used as a basist to determine the appropriate frequency for future inspections.
Nuclear NS-C-1A 04/21/88 05/23/86 The NSRW system supplies cooling water to the four (4)~
Services 09/03/84 Nuclear Services Heat Exchangers. The NSRW Heat River Water 11/02/82 Exchangers are currently inspected on a biennial basis (NR) in accordance with the TMI Preventive Maintenance NS-C-1B 03/09/89 08/24/87 Program. These heat exchangers are currently scheduled.
09/03/84 to be inspected during 1990. -The. frequency of this 07/14/82 inspection-may be revised based on the results and.
frequency of previous inspections.
NS-C-1C 11/20/87 09/16/84 05/27/82 NS-C-1D 04/08/88 09/15/84 04/12/83 08/06/82 _
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ATTACHMENT'21
, 4-INSPECTION PROGRAM FOR OPEN-CYCLE HEAT EXCHANGERS HEAT LAST FREVIOUS SYSTEM EXCHANGER INSPECTED INSPECTIONS COMMENTS-RB Emergency AH-E-1A N/A N/A The primary function of the RR System is to remove heat from the RB in the event of a LOCA, and to reduce.the Cooling River AH-E-1B' Water (RR)
AH-E-1C pressure and the driving force for RB leakage. A program-does not currently exist to inspect the RB Emergency Cooling Coils for biofouling. 'Thus, GPU Nuclear will evaluate whether the capability exists to inspect the water side of the RB Emergency Cooling Coils. This:
evaluation will be completed prior to completion of the 8R outage.
If possible, GPU Nuclear will, as a minimum, inspect one (1) cooling coil per refueling-outage,.
starting with the 9R Outage. This frequency may be adjusted after all three (3) cooling coils are inspected.
If our evaluation determines that it is not practical to inspect the RB Emergency Cooling Coils, GPU Nuclear will inform you of our alternative actions. The RR System is layed up with the NSCCW System which is treated with a corrosion inhibitor. Furthermore, inservice testing of the RR System pumps and valves is performed each refueling interval.which verifies.the operability of the RR System.
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- ATTACHMENT'2-INSPECTION PROGRAM FOR OPEN-CYCLE HEAT EXCHANGERS.
HEAT LAST PREVIOUS SYSTEM
~ EXCHANGER INSPECTED INSPECTIONS.
COMMENTS
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Screen House AH-E-27A N/A N/A.
An appropriate method of evaluating the SW cooling:
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' Ventilation AH-E-27B coils is to establish an inspection program for the Cooling Water heat exchangers. GPU Nuclear plans to inspect the -
Syster (SW) water side of the SW cooling coils on a' routine basis as.
.part of the Preventive Maintenance Program. Due to the-
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potential-for silt accumulation and the potential for Asiatic clam biofouling, these units will~ be placed on the PM Program for-inspection of one (1) cooler per year. This frequency may be. adjusted after both cooling coils have been inspected.
Inspection is possible by.
removal of the water manifolds which exposes all cooling tubes.
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