ML17296B068
| ML17296B068 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 11/21/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Van Brunt E ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| References | |
| NUDOCS 8012040538 | |
| Download: ML17296B068 (8) | |
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UNITEDSTATES NUCLEAR REGULATORY COMMISStON REGION V 1990 N. CALIFORNIABOULEVARD SUITE 202. WALNUTCREEK PlAZA WALNUTCREEK, CAI.IFORNIA94596 November 21, 1980 Docket Nos 50-528, 50-529, 50-530 Arizona Public Service Company P. 0.
Box. 21666 Phoenix, Arizona 85036 Attention:
Nr. E. E.
Van Brunt, Jr.
Vice President,.
Nuclear Projects Gentlemen=
Enclosed is If Bu'l'letin No., 80-24 which is transmitted for information with regard'o your nuclear power facility.
Should you have any questions'egarding this bulletin, please contact this office.
Sincerely, R;
H. Engelken Director
Enclosures:
1.
Recently Issued IE Bulletins I
cc w/enclosures:
F.
M. Hartley, APS
l
UNITED STATES OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 November 21, 1980 SSINS Ho.:
6820 Accession No.:
8008220270 IEB 80-24 IE Bulletin No. 80-24:
PRP/ENTION OF DAMAGE DUE TO WATER LEAKAGE INSIDE CONTAINMENT (OCTOBER 17.
1980 INDIAN POINT 2 EYENT)
Descri tion of Circumstances:
On October 24, 1980 IE Information Notice No. 80-37 described an event that occurred at the Indian Point Unit 2 (IP-2) facility.
On October 17,
- 1980, upon containment entry for repair to a nuclear instrument, it was discovered that several inches of water had accumulated on the containment floor without the operators'nowledge.
This accumulation was later determined to have amounted to over 100,000 gallons which flooded the reactor-vessel pit and wetted the lower nine feet of the reactor vessel while the reactor was at. operating temperature.
The flooded condition resulted from the following combination of conditions:
(1) There were significant multiple service water leaks from piping-and fan coolers onto the containment floor..
Tnis system had a history of leakage; (2) Both containment sump pumps were inoperable, one due to blown fuses and the other due to binding of its float switch; (3) The significance of two containment sump level indicating lights which indicated that the water level was continuously above the pump-down level was not recognized by the operators;-
(4) There was no nigh water level alarm and the range of sump level indicating lights failed to indicate the overflowing sump. level; (5) The moisture level indicators for.he containment atmosphere did not indicate high moisture levels, apparently due to an error in calibration and/or ranging which made them insensitive to the moisture levels resulting from relatively small cold water leaks; (6) The hold-up tanks which ultimately receive water pumped from the containment sump also received water from other sources (Unit 1 process
- water, lab drain water, etc).
These other water sources masked the effect of cessation of water flows rem the Unit 2 sump; (7) The fan cooler condensate wier level measuring instruments were not properly calibrated; (8) There was no water level instrumentation in the reactor vessel pit and the pumps were ineffective since they discharge to the containment floor for ultimate removal by the.
containment sump pumps.
This Bulletin is issued to enable the NRC staff to formulate requirements for long term generic corrective actions which will be the subject(s) of future NRC actions.
The bulletin requires short term actions which will preclude IP-2 type events at other plants in the interim before the longer term generic actions are accomplished.
1
IEB 80-24 November 21, 1980 Page 2 of 3 Actions to be Taken b
Licensees:
1.
Provide a sugary 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 LOCA; (b) Source of water and typical chemical content of
~
water; (c) Materials used in piping and coolers; (d) Experience with system leakage; (e) History and type of repairs to coolers and piping systems (i.e., replacement, weld, braze, etc.); (f) Provisions for isolating portions of the system inside containment in the event of leakage including vulner-ability of those isolation provisions to single failure; (g) Provisions for testing isolation valves in accordance with Appendix J to 10 CFR 50 (h) Instrumentation (pressure, dew point, flow, radiation detection, etc.)
and procedures in place to detect leakage; and (i) Provisions to detect radioactive contamination in service water discharge from containment.
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 room operators of a significant accumulation of water in containment (including the reactor vessel 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.
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 recorrmended that continued power operation be limited to seven days and added surveillance measures be instituted.
- d. Review leakage detect~on 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 n
pen system uti izes an indefinite volume, such as a river, so that leakage from the system could not be detected by inventory decrease.
In 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.
IEB 80-24 November 21, 1980 Page 3 of 3 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 atmosohere 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 soecial 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.
3.
For plants, with closed cooling water systems inside. containment provide a summary of experiences. with cooling water system leakage into containment.
4.
Provide a written. report, signed under oath or affirmation, under the provi-sions of Section 182a-of the Atomic Energy Act of 1954, in response to the above i'tems within 45 days of the date of this bulletin.
Include in your report where applicable, your schedule for completing the actions in response to items 2 (a) through (d).
Your response should be sent to the Director of 'he appropriate Regional Office with a copy forwarded to the Director, NRC,. Office of Inspection and Enforcement, Mashington, O.C.
20555.
If you desire additional information regarding this matter please contact the appropriate IE Regional Office.
Approved by GAO, 8180225 (R0072); clearance expires November 30, 1980.
Approval was oiven under a blanket clearance speci ically for identified generic problems.
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