ML20082H118
| ML20082H118 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 08/18/1991 |
| From: | Broughton T GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| C311-91-2055, GL-89-13, NUDOCS 9108230090 | |
| Download: ML20082H118 (3) | |
Text
'
e
(
I ENuclear
- = o==a GPU Nuclear Corporation M6ddletown, Pennsylvania 17057 0191 717 944 7621 TELEX 842386 Writer's Direct Dial Number:
(717) 948-8005 Atr3usb 18,1991 C311-91-2055
- 9. S. Nuclear Regulatory Commission
~
Attn: Document Control Desk Washington, D.C.
20555
Dear Sir:
Subject:
Three Mile Island Nuclear Station, Unit 1 (TMI-1)
Operating License No. OPR-50 Docket No. 50-289 Generic letter 89-13 Response to Recommended Action IV GPU Nuclear letter C311-89-2115 dated January 26, 1990, responded to Generic Letter (GL) 89-13, " Service Water System Problems Affecting Safety-Related Equipment." In response to Recomr. ended Action IV of GL 89-13, the referenced GPU Nuclear letter committed to conduct a single failure analysis of the TM1 open-cycle and closed-cycle service water systems that met the-criteria of GL 89-13.. Attached are the results of this analysis.
The response to Recommended Action IV also committari tn performir.g an audit to assess the operational readiness of the - Nuclear Services Closed Coeling. Water System. This actica is ongoing. Confirmation of the completion of this action will be provided in a docketed submittal no later than 30 days af ter plant startup following the 9R outage pursuant to the recommendations of GL 89-13.
The referenced GPU Nuclear letter also stated that annual sampling of the York Haven Pond for Asiatic Clams would continue until an effective biocide treatment program was established. The intent of the_ pondwide sampling was to detect encroachment of Asiatic Clams into the TMI area and to monitor the distribution within the pond.
?
Presently, Asiatic Clams have populated the pond in sufficient nurrbers to sustain a viable crowing population and a biocide treatment has been established.
The program was implemented in November-1990 and June 1991 on the river water and fire service - systems using Betz Clam-Trol CT-1.
Data from the June 1991 treatment indicates that 100% mortality of the clams exposed to the biocide was achieved.
Although futi!re treatments may not attain.100% mortality values, the use of Clam-Trol CT-1 has been estab18 shed as an effective biocide treatment for Asiatic Clams.
9100230090 910818 PDR ADOCK 05000289 P
PDR (4 g f" A
~ ;, v v GPU Nuclear Corpoiation is a subsidiary of General Public Utihties Corporation
/
Document Control Desk e-C311-91-2055 page ?
Since the presence of Asiatic C'ams in the TM1 area has been established and an ef fective biocide treatment pro, ram instituted, GPU Nuclear is deleting the annual pondwide sampling.
Sampling of t.he TMI-1 intake bay will continue to track clam.
growth and help determine the f equency and ef fectiveness of the biocide treatment program.
GPU Nuclear believer that this program (i.e., an effective biocide treatment progrcm coupled with inspection and sampling of the intake structure) satisfies the recommended surveillance and control techniques provided in Enclosure 1 to GL 89-13.
Sincerely,
$N%
T.G.Brouditon Vice President and Director, lM1-1 RDW Attachment cc:
R. Hernan - Senior Project Manager T, Martin - Regional Administrator-F. Young - NRC Sr Resident Inspector TM!-
l.
1 n
D'ocument Control Desk Attachment
, g.
C31.1-91-2055 Page 3 Response To GL 89-13, Recommended Action IV 3
Recommended Action IV requested licensees to confirm the ability of service water systems "... to perform required safety functions in the event of failure of a single active component." Gpu Nuclear letter C311-89-2115 dated Jant.ary 26, 1990, indicated that the following service water systems were within the scope of GL 89-13:
Open-Cycle Systems Closed-Cycle Systems Decay Heat River Water (DR)
Decay Heat Closed Cool'ng Water (DHCCW)
Nuclear Services River Water (NR)
Nuclear Services Cooling Water (NSCCW)
Reactor Building Emergency Cooling Water (RR)
Screen House Ventilation Cool:ng Water (SW)
Since the submission of GPU Nuclear's response to GL 89-13, the SW system has been declassified from " Nuclear Safety Related" to "Other" (reference GPU Nuclear Safety Evaluatic,a 000820-001, rev. 0).
GL 89-13 defines a service water system as "the system or systems that transfer heat from safety-related structures, syst1ms, or components to the Ultimate Heat Sink (UHS)."
The SW system no longer performs a safety related function. Therefore, this system is not within the scope of GL 89-13 and Recommended Action IV no longer applies to this system.
A review of the design basis for the NR and NSCCW systems determined that these systems were designed to be redundant (reference FSAR Sections 9.6.1 and 9.6.21),
but not single f ailure proof (reference GAI Specifiet.icns R-?2. B-23).
inis includes the electrical portions of both safety related systems. This determination is further based on a review of the " Final Report: Three-Mile Island Unit 1 Emergency Core Cooling System (ECCS) Single Failure Analysis." This analysis, which includos the NR and NSCCW systems, states that enough redundancy exists in the ECCS such that the ECCS is' capable of performing its intended function given a single active failure. These efforts meet the intent of GL 89-13 by providing assurance that the NR and NSCCW systems will function as required.
Therefore, no further action is_ required for the NR and NSCCW systems, since it is not the intent of Recommended Action IV ot GL 89-13 to change the design basis of the system.
Single failure analyses (mechanical and electrical) were performed for the DR, RR, and DHCCW systems (reference GpU Nuclear memorandum 5360-91-052 dated April 5, 1991). Each of these analyses confirmed the ability of the respective service water system to perform required safety functions in the event of f ailure of a single active compot.ent.
In accordance with the requirements of GL 89-13, documentation of the above analaes is not required to be submitted to the NRC, but are retaineo on file for NRC review.-