ML19347C880
| ML19347C880 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 01/22/1981 |
| From: | Hukill H METROPOLITAN EDISON CO. |
| To: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| IEB-80-24, TLL-694, NUDOCS 8103100219 | |
| Download: ML19347C880 (4) | |
Text
'T h Metropolitan Edison Company Post Office Box 480
=
Middletown, Pennsylvania 17057 717 944 4041 Wnter's Direct Dial Number January 22, 1981 TLL 694 Office of Inspection & Enforcement e
'p Astn:
B. H. Grier, Director g
Region I 4
U. S. Nuclear Regulatory Commission g
631 Park Avenue f
King of Prussia, Pa.
19406 08-7 g%
Ab /g /
g A
Dear Sir:
2 g
O Three Mile Island Nuclear Station, Unit 1 (TMi 3
Operating License No. DPR-50 m
Dockat No. 50-289 TE Bulletin 80-24 Attached please find our response to the subject bulletin concerning damage due to water leakage inside containment.
The preparation of this response required 30 manhours.
Sincerely, H. D. Hukill Director, TMI-l HDH:DGM: hah Attachment ec:
R. W. Reid B. J. Snydcr D. Dilanni H. Silver L. Barrett 19 81031002 Metreochtan Edrson Company is a Member of the General Pubhc Utihties Systern
TLL 694 ITEM 1:
Provide a summary description of all open cooling water systems present inside. containment. Your description of the cooling water systems must include:
(a) Mode of operation during routine reactor operation and in response to a L.O.C.A.:
Response: The only open system in containment is the Reactor Building Emergency River water system.
During normal operations this system is passive, under =
100 psig pressure provided by the Nuclear Se,rvice Closed Cooling System, under L.O.C.A. conditions the system is in operation under = 60 psig provided by a regulating valve.
(b)
Source of water and typical chemical content of water:
Response:,The source of water is directly from the river.
The intake pump house automatically adds chlorine to the water.
(c) Materials used in piping and coolers:
Response.
Pipes are made of carbon steel. Coolers are made of copper.
(d)
Experience with system leakage:
Response: There hasn't been any detectable leakage other than minor packing leakage on a non routine basis.
(e) History and type of repairs to coolers and piping systems (i.e.
replacement, weld, braze, etc.):
Response
Since initial installation, no repairs have been performed on piping or coolers.
(f) Provisions for isolating portions of the system inside containment in the event of leakage including vulnerability of those isolation provisions to single failure:
Response
Each cooler can be isolated by motor operated valves.
If a poeer shortage occurs, each motor has a hand operator attached. All valves are located outside containmect.
(g) Provisions for testing isolation valves in accordance with Appendix J to 10 CFR 50:
Response: Per 10 CFR 50 Appendix J Section II B, those valves do not apply. This system is in operation during a L.O.C.A. with a minimum of 60 psig pressure on coolers.
Valves are tested as part of the ESAS system.
(h)
Instrumentation (pressure, dew point, flow, radiation detection, etc.)
and procedures in place to detect leakage:
Response: Overhead alarms which annunciate on differential flow will indicate leakage during L.O.C.A. operation.
An alarm is provided for each cooler and individual flow indicators are provided in the plant outside of contain-ment. A lenk detector failure alarm is also provided for this detection scheme.
During passive operation, a leak can be detected from any source by an additional alarm in the control room.
In order to determine which cooler is leaking, a R.B. entry must be made.
(i) Provisions to detect radioactive contamination in service _ water discharge from containment:
Response: The discharge of this system is through a plant effluent monitor RML-7.
It should be noted that system leakage is into containment.
'2.
For plants with open cooling water systems inside containment take the followink actions:
(a) Verify existence or provide redundant means of detecting and promptly alerting control room operators of a significant accumulation of water in containment (including the reactor vessel pit if present).
Response: Overhead alarms in addition to indicating lights are provided. Varying degrees of level will actuate different lights.
Level indication for R.B. sump and containment building level is being provided.
(b) Verify existence or provide positive means for control room operators to determine flow from containment su=p(s) used to collect and remove water from containment.
Response
In the control room the operator has indicating lights, alarms, and level indicators to corrolate decreasing R.B. sump level. - In addition, in that the method of removal is manual actuated gravity draining to the auxiliary building sump, the auxiliary building sump level indication in the control room can be used to verify increasing level during R.B. sump level draining.
(c) Verify or' establish at least monthly ' surveillance procedures, with appropriate operating limitations, to assure plant operators have at least two methods of-determining water level in each location where water may. accumulate. The surveillance procedures shall assure that at least one method to remove water from each such' location is available'during power operation. ' In the event either the detection or removal systems become inoperable it is recommended that continued power operation be limited to seven days and added surveillance measures be. instituted.
Response: Due to redundant-instrumentztion provided to the operator, an additional surveillance procedure is not required.
Sufficient guidance is provided in existing procedures.
..m
..... m
- m..
.m
.A -
.-.m
..m
Sivaral methods of level indication are provided for the containstnt sump (see rest onse tc 2a).
Surveillance procedures already implemented assure at least one method of water removal. Therefore, we feel there is no need to' limit power operations in the event either the detection or removal systems become inoperable. However, we will increase surveillance of the building.
(d) Review leakage decection systems and procedures and provide or verify ability to promptly detect water leakage in containment, and to isolate the leaking components or system. Periodic containment entry to inspect for leakage should be considered.
Respoase:
The leakage detection systems during a L.O.C.A. and normal operations are discussed in response lh.
Response
procedures for these alarms provide adequate guidance for the operator. The response to 2c covered containment entry.
(e) Beginning within 10 days of the date of this bulletin, whenever the reactor is operating and until the measures described in (a) through (d) above are implemented, conduct interim surveillance measures.
The measures shall include where practical (considering containment atmosphere and ALARA considerations) a periodic containment inspection or remote visual surveillance to check for water leakage.
If containment entry is impractical during operation, perform a containment inspection for water leakage at the first plant shutdown for any reason subsequent to receipt of this bulletin.
Response: -A change was made to Operations Surveillance to reflect a visual inspection.
(f)
Establish procedures to notify the NRC of any service water system leaks within containment via a special licensee event report (24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with written report in 14 days) as a degradation of a containment boundary.
Response: TMI-1 utilizes only one open system in the containment.
Our. responses show that adequate measures are being taken to ensure leaks are detected in a timely manner and ensure containment flooding is prevented.
The issuance of a prompt report will not increase leak detection or prevent containment flooding.
Therefore, clarification is requested prior.to initiation of this item.
3.
For plants with closed cooling water systems-inside containment, provide a summary of experiences with cooling water system leakage into containment.
Response:- It has been our experience that only minor leakage has occurred from our closed systems as described in the response to item id.
..