ML20053E007
| ML20053E007 | |
| Person / Time | |
|---|---|
| Site: | Crane  |
| Issue date: | 05/26/1982 |
| From: | J. J. Barton GENERAL PUBLIC UTILITIES CORP. |
| To: | Haynes R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| References | |
| REF-SSINS-6820 4400-82-L-0051, 4400-82-L-51, IEB-80-24, NUDOCS 8206070522 | |
| Download: ML20053E007 (6) | |
Text
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GPU Nuclear 7]
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P.O. Box 480 Middletown, Pennsylvania 17057 717-944-7621 Writer's Direct Dial Number.
May 26, 1982 4400-82-L-0051 Office of Inspection and Enforcement Attn:
Mr. Ronald C. Haynes, Director Region I U. S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pennsylvania 194d6
Dear Sir:
Three Mile Island Nuclear Station, Unit 2 (TMI-2)
Operating License No. DPR-73 Docket No. 50-320 I & E Bulletin 80-24
Reference:
Letter; Boyce Grier (NRC) to R. C. Arnold (Met-Ed)
Dated November 21, 1980 Regarding I & E Bulletin 80-24 The following is GPUN's response to I & E Bulletin 80-24 regarding prevention of damage due to water leakage inside containment.
The requested short term actions to preclude Indian Point-2 type events are not appropriate for TMI-2 due to the current Post Accident Condition. However, the attached information (Attachment "A") provides GPUN's response to I & E Bulletin 80-24 considering the present situation at TMI-2.
Sincerely,
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f J g arton e 't g Director TMI-2 JJB:SWS:djb Attachment cc:
L. H. Barrett, Deputy Program Director - TMI Program Office Dr.
B. J. Snyder, Program Director - TMI Program Office I
b 8206070522 820526 1
1 PDR ADOCK 05000320 Q
PDR ear is a part of the General Pubhc Utilities System
a ATTACINENT A Request 1 Provide a summary description of all open* cooling water systems present Your description of the cooling water systems must inside containment.
include:
(a) Mode of operation during routine reactor operation and in response to a LOCA: (b) Source of water and typical chemical content of water: (c) Materials used in piping and coolers: (d) Experience with (e) History and type of repairs to coolers and piping system leakage:
systems (i.e., replacement, weld, braze,.etc.); (f) Provisions for isolating portions of the system inside containment in the event of leakage including vulnerability of those isolation provisions to single (g) Provisions for testing isolation valves in accordance with failure:
(h) Instrumentation (pressure, dew point, flow, Appendix 3 to 10 CFR SO:
radiation detection, etc.) and procedures in place to detect leakage; and (1) Provisions to detect radioactive contamination in service water discharge from containment.
Response 1 The only open cooling water system in Unit 2 is the Reactor Building Emergency Cooling System. This system is placed in service only during emergency (LOCA) conditions.
Normal Reactor Building cooling is accomplished through a closed system.
(a) The modes of operation during routine reactor operation and in response to a LOCA are as follows:
tbrmal Operation During normal system operation, the RB Emergency Cooling System (open system) is shutdown.
Emergency (0 pen System - LOCA)
Four of the five Reactor Building fan coil cooling units are normally The inlet valve of the opr13ted using the normal cooling water system.
idle fan coil unit is shut, and all the Reactor Building Emergency On an SFAS signal, the six inlet Cooling water booster pumps are idle.
valves to the five cooling units open and the Reactor Building normal cooling outlet valves close. Pump suction is taken from the Nuclear River water headers. Discharge is to the Nuclear River Water return headers to the river via the Mechanical Draft Cooling Tower.
An Open system utilizes an indefinite volume, such as a river, so that In leakage from the system could not be detected by inventory decrease.
addition, a direct radioactive pathway might exist to outside containment in the event of a LOCA simultaneous with a system leak inside containment. A closed system utilizes a fixed, monitored volume such that leakage from the system could be detected from inventory decrease and a second boundary exists to prevent loss of containment integrity as a result of a system leak inside containment.
ATTACWENT A (CON'T)
During a LOCA, only two Reactor Building cooling units are required.
If during a LOCA, loss of normal power and loss of a diesel occur simultaneously, only one pump will run and supply water to three fan coil units.
(b) The source of the cooling water from the Reactor Building Emergency Cooling Water System is the Susquehanna River.
Typical chemical content of this water is:
i pH - 7.9 Cond. - 128-300 p MHOS Alkalinity - 50 as CACO 3 mg/t Fe - 0.5-2.5 mg/t Suspended Solids 80 mg/t Dissolved Solids - 170-200 mg/t Na+ 11 mg/t (c) Materials l
Pipe 1/2" to 8" Carbon Steel, ASTM A106, Grade B, Type S Seamless -
Schedule 80.
10" - 24" Carbon Steel, ASTM A106, Grade B, Typ S Seamless - Extra Strong (XS)
Cooler 90-10 Cupro-Nickel (ASTM B-ll) in cooling coils Flange on Coils Steel ASTM-A-234 (d) Experience With System Leakage - March 28, 1979 and Afterwards Relief valves on Reactor Building cooling coils lifted during TMI-2 Accident when the Reactor Building Emergency Cooling System was placed in service. This leakage was eliminated by switching mode of cooling to Reactor Building Normal Cooling System.
(e) History and Type of Repairs to Coolers and Piping Systems.
Around July 5, 1979: Reactor Building Emergency Cooling Coil Back Pressure Controller would not regulate. Troubleshooting has been delayed due to building accessibility.
This is the only known repair to coolers and piping.
(f) Provisions For Isolating Portions of the System Inside Containment in the Event of Leakage Including Vulnerability of Those Isolation Provisions to Single Failure.
Double valve isolation on both the inlet and the outlet of the cooling units is available.
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ATTACHMENT A (CON'T)
(g) Provisions for Testing Isolation Valves in Accordance to Appendix J to 10CFR50.
Type B tests on the containment penetration sleeves have been conducted prior to the accident'in accordance with Surveillence Procedure 2313-R7, Step 6.21.
These tests were performed with a gas at 56.2 psig at required ~ intervals of no greater than 24 months.
The NRC has granted an exemption from Appendix J testing of containment isolation valves.
(h)
Instrumentation and Procedures in Place to Detect Leakage; tte Only Instrumentation Provided in the TMI-2 Design that Could Have Detected Leakage of the Type Associated with the IP-2 Problem is as follows:
1)
Reactor Building Cooler Pan Level Switches - the plant design includes level switches in the drip pans under the cooler units to detect leakage. One float type level switch device is located under each cooler. The drip pan then drains to the Reactor Building sump. These devices would only detect a leak in the area of the cooling coil itself.
2)
Reactor Building Sump Level Indicator - Reactor Building sump 1
level is routinely monitored in accordance with operating procedure 2104-4.47.
(i) Provisions to Detect Radioactive Contamination In Service Water Discharge from Containment.
1)
As specified previously, the only open service water system at TMI-2 is the Reactor Building Emergency Cooling System. As this system is currently tagged out of service, provisions for radioactive contamination in the discharge path are not applicable. However, the main effluent monitor does monitor the combined discharge to the river.
Request 2 For plants with open cooling water systems inside containment take the following actions:
(a) Verify existence or. provide redundant means of detecting and promptly alerting control rocm operators of a significant 4
accumulation of water in containment (including the reactor vessel j
pit if present).
(b) Verify existence or provide positive means for control room operators to determine flow from containment sump (s) used to collect and remove water from containment.
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ATTACENENT A (CON'T)
(c) Verify or establish at least monthly surveillance procedures, witn 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.
(d) Review leakage detection 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.
(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.
(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 2 The information requested in item 2 is for " Plants with open coolirg water systems inside containment". For TMI-2,~ the only open cooling water system is the Reactor Building Emergency Cooling System as identified in the response to item #1. However, since shortly after the accident at THI-2 the Reactor Building Emergency Cooling System has been placed out of service and " Red-Tagged".
Since the Reactor Building Emergency Cooling Water was designed for service during a LOCA condition, and with the present condition of TMI-2, there is no currently foreseeable circumstance under which this system would be required. Therefore, the e if.h: concerns requested to be addressed do not apply to TMI-2 in Jta pn tent condition.
In addition, monitoring of water level it' e e r stor building as it applies to the unique situation at ?ti I
a.htessed on a situation by situation basis and is also included in the ec overy Operations Technical Specifications.
ATTACHMENT A (CON'T)
Request 3 For plants with closed cooling water systems inside containment provide a summary of experience with cooling water system leakage into containment.
i Resnonse 3 t
Currently, leakage into the containment from closed cooling water i
systems is identified as approximately 0.06 GPM. The amount of leakage is determined by the makeup required for the standby pressure control system. Due to present radiological conditions inside the containment it is not practical to determine the exact location of the leak and the leakage is not a problem at this time.
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