ML19345C345
| ML19345C345 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay |
| Issue date: | 11/21/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 8012040465 | |
| Download: ML19345C345 (1) | |
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NUCLEAR REGULATORY COMMISSION jf
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z November 21, 1980 9F*
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5 Docket No. 50-133 4
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Pacific Gas and Electric Company i
'77 Beale Street San Francisco, California 94106 4
4 Attention: Mr. Philip A. Crane, Jr.
Assistant General Counsel Gentlemen:
Enclosed is IE Bulletin No. 80-24 which requires action by you with
' regard to your nuclear power facility (ies) with an operating license.
-In order to assist the NRC in evaluating the value/ impact of each bulletin on. licensees, it would be helpful if you would provide us an' estimate of the manpower expended in conduct of the review and preparation of the report (s) required by the bulletin. Please estimate separately the manpower associated with corrective actions necessary following identification of problems through the bulletin.
Should you have any questions regarding this bulletin or the actions required by you. please contact this office.
j Sincerely, l.
lliT% MAN-R. H. Engelken Director
Enclosures:
1.
Recently Issued IE Bulletins cc w/ enclosures:
.J. D. Shiffer, PG&E W. Raymond, PG&E l
E. Weeks, PG&E, Humboldt Bay i
-,o-801204 6
1 SSIfiS No.: 6820 Accession ?!o.:
8008220270 IEB 80-24 Ul!ITED STATES OFFICE OF INSPECTI0ft AND EllFORCEftEfiT MASHIMGTON, D.C.
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November 21, 1980 3*
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1 IE Bulletin No. 80-24:
PREVENTION OF DAMAGE DUE TO WATER LEAKAGE INSIDE CONTAINMENT (OCTCBER 17, 1980 IllDIAN POINT 2 EVENT)
Description of Circumstances:
On October 24, 1980 IE Information Notice t'o. 80-37 described an event that occurred at the Indian Point Unit 2 (IP-2) facility.
On~0ctober 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' knowledge. 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 i
temperature.
The flooced condition resultea from the following combination of conditions:
(1) There were significant multiple service water leaks from piping and fan coolers onto the containment floor. This 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 ficat switch; (3) The significance of two containment sump level inoicating lights which indicated that the water level was continuously above the pump-down level was not. recognized by the operators; (4) There was no high water level alarm and the range of sump level indicating lights failed to indicate the overflowing sump level;-(6) The moisture level indicators for the 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 frcm other sources (Unit 1 process water, lab drain water, etc). These other water sources masked the effect of cessation of water flows frcm 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 sunp pumps.
This Bulletin is issued to enable the NRC staff to formulate requiremcnts 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 interin before the longer term generic actions are accomplished.
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IEC 80-24 flovember 21, 1980 Page 2 of 3 Actions to be Taken by Licensee _s:
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 LOCA;-(b) Source of water and typical chemical content of water; (c) Materials used in piping and coolers; (d) Experience.with system leakaga; (e) History and type of repairs to coolers and piping systems (i.e., t aplacement, weld, braze, etc.); (f) Provisions for isolating portions of the system inside containment in the event of leakage including vulner-ability of those isclation 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.
i 2.
For plants with open cooling water systems inside containment take the following actions:
f 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 frcm containment sump (s) used to collect and remove j
water from containment.
c.
Verify or establish at least monthly surveillance procedures, with appropriate operating limitations, to assure plant operators have i
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 povier operation.
In the event either the detection or removal systems become inoperable it is recommended that continued power i
operation be limited to seven days and added surveillance measures 1
be instituted.
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- 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 contaircent entry to inspect
- An Open system utilizes an indefinite volume, such as a river, so that leakage frem 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 frem 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.
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IEB 80-24 November 21, 1980 Page 3 of 3 for leakace should be censidered.
e.
Beginnino 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 imolemented, conduct interim surveillance reasures.
The measures shall include where practical (considering containrent atmoschere and ALAPA consideratiens) a periodic contair. ment inspection or remote visual surveillance to check for water leakage.
If containment entry is impractical during operation, perform a containment inspection fcr 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 degracaticn 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 unaer oath or affirmation, under the provi-sions of Section 18Ea of the Atomic Energy Act of 1954, in response to the above itens within 45 days of the date of tFis bulletin.
Include in your report wiiere applica' ole, your scheduie for completing the actions in resconse to itcas 2 (a) thrcugn (d). Ycur response should be sent to the Director of the appropriate Regional Office with a copy forwarded to the Director, MRC, Office of Inspection and Enforcement, Washington, D.C.
20555.
If you desire additicnal information regarding this matter please contact the appropriate IE Regional Office.
Approved by GAO, CICG225 (R0072); clearance expires McVember 30, 1980.
Approval was given under a blanket clearance specifically for identified generic problems.