ML20151L129
| ML20151L129 | |
| Person / Time | |
|---|---|
| Issue date: | 09/06/1985 |
| From: | Taylor J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | Stello V NRC OFFICE OF THE EXECUTIVE DIRECTOR FOR OPERATIONS (EDO) |
| Shared Package | |
| ML19284F128 | List: |
| References | |
| NUDOCS 8509110406 | |
| Download: ML20151L129 (7) | |
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UNITED STATES
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NUCLEAR REGULATORY COMMISSION o
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wAsWNGTON D. C. 20555 j
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MEMORANDUM FOR:
Victor Stell'o, Jr., Deputy Executive Director for Regional Operations and Generic Requirements FROM:
James M. Taylor, Director Office of Inspection and Enforcement
SUBJECT:
REQUEST FOR CRGR REVIEW OF PROPOSED IE BULLETIN 85-XX: STEAM BINDING OF AUXILIARY FEEDWATER PUMPS I
Please schedule a CRGR review of the proposed subject bulletin (Enclosure 1).
This bulletin is considered to be a Category 2 item as specified in the CRGR charter. We suggest a CRGR meeting September 25, 1985.
This bulletin was prepared because NRC review of licensee actions, in followup to Institute for Nuclear Power Operations (INPO) Signicant Operating Experience L
1 Report (50ER) 84-3 and IE Information Notice 84-06, indicated that adequate and
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lasting provisions to protect against steam binding were not instituted (Enclo-sure 2).
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The proposed bulletin requests that. action andressees develop and implement procedures for monitoring fluid conditions in the auxiliary feedwater system, for recognizing steam binding and for restoring the auxiliary feedwater system to operable status if steam binding should occur. The action addressees are those operating PWRs that do not have such procedures, as determined by a staff survey, and PWRs under construction that have not been surveyed. These actions are inter.ded to correct a potentially significant risk that could result fromt
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the unreliability of the auxiliary feedwater system with respect to the recent-ly studied phenomenon of steam binding. Any licer,ee that has followed the L_ '
recommendations of the INP0 in their 50ER 84-3 will have exceeded these requirements.
J Contacts: Mary Wegner, IE, 24511 Vern Hodge, IE, 27275 b
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Victor Stello, Jr.
- The effect of the proposed bulletin is assessed in Enclosure 3.
We estimate the total cost of this proposed bulletin to be about $100,000 to NRC and about
$800,000 for one-time effort and $300,000 per year for continuing effort to lit:ensees and applicants, with no attendant increases in occupational dose or complexity of plant or operatiori.
L James M. Taylor, Director Office of Inspection and Enforcement J
Enclosures:
1.
Proposed IE Bulletin 2.
Memo from Jordan to Taylor (July 16,1985),"SteamBindingin F
Auxiliary Feedwater Systems" I
3.
Information for CRGR Review 4.
IE IN 84-06, " Steam Binding of Auxiliary Feedwater Pumps" P
5.
INPO SER, "Backleakage Disables Auxiliary Feedwater Pump" 6.
INPO SOER, " Auxiliary Feedwater Pumps Disabled by Backleakage" 7.
AEOD Case Study Report C404, " Steam Binding of Auxiliary Feedwater Pumps" r
8.
Memo from Bernero to NRR Division Directors (June 25,1985)," Generic p-Issue No. 93" f
9.
Generic Issue 93, " Steam Binding of Auxiliary Feedwater Pumps"
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DISTRIBUTION:
DCS DEPER R/F EGCB R/F JMTaylor, IE
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DAllison, IE VHodge, IE MWegner, IE CERossi, IE EFox, IE KSeyfrit, AEOD he WLanning, AEOD HDenton, NRR GHolahan, NRR Glainas, NRR ii OParr, NRR GWermeil, NRR RWessman, NRR JPittman, NRR
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LRubenstein, NRR WMinners, NRR FMiraglia, NRR HThompson, NP3 DEisenhut, NRR BShelton, ADM SScott, ADM VHodge R/F t
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I I-OMB No.: 3150-0011 o
Expiration Date:
9/30/85 F
IEB 85-XX UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT KASHINGTON, D.C.
20555
' August, 1985 s;
IE BULLETIN 85-XX: STEAM BINDING OF AUXILIARY FEEDWATER PUMPS r
Addressees:
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For Action - Those nuclear power reactor facility licensees i.nd construction permit (CP) holders listed in Attachment 1.
For Information - All other nuclear power reactor facilities.
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Purpose:
I The purpose of this bulletin is to inform licensees and CP holders of a poten-tially serious safety problem that has occurred at certain operating facilities involving the inoperability of auxiliary feedwater (AFW) pumps as a result of steam binding. Certain PWR licensees and all PWR CP holders are requested to take further action to prevent similar events from occurring at their facili-
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ties and to document those actions taken or planned.
Description of Circumstances:
Numerous events have been reported where hot water has leaked into AFW systems and flashed to steam, disabling the AFW pumps.
Events at Robinson 2 in 1981.
ed through 1983, Crystal River 3 in 1982 and 1983, and D. C. Cook 2 in 1981 weret summarized in IE Information Notice (IN) 84-06, issued in January of 1984.
r Also in January of 1984, the Institute of Nuclear Power Operations (INPO)
It issued Significant Event Report (SER) 5-84 detailing events at Robinson 2 and L
Report (50ER)pril of 1984, INP0 issued a Significant Operating Experience Farley.
In A J.
84-3 that discussed another event at Surry 2 in 1983.
t The NRC's Office for Analysis and Evaluation of Operational Data (AE00) issued a case study report entitled " Steam Binding of Auxiliary Feedwater Pumps" in July of 1984.
This study identified 22 events since 1981; 13 of these occur-ring in 1983.
Based on operating experience, it appears that backleakage into AFW could occur in any PWR.. In a number of plants, the two motor-driven, pumps feed into a single pipe which feeds into the steam generator; therefore, a leaking valve in that pipe increases the probability of steam binding in both t
trains,of AFW. Also, multiple AFW pumps often take suction from a_ common I
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IEB 85-XX f-August 1985 Page 2 of 4
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F manifold; therefore, if one pump becomes steam bound because of leaking check valves, the steam can heat the common suction and cause other pumps to have inadequate net positive suction head (NPSH).
AFW capability is needed for normal shutdown and transient conditions as well as for accident mitigation. The AEOD case study examined the effects of steam binding on a sequence in which there was a loss of the power conversion (stsam generation) system after a transient other than loss-of-offsite power. A probabilistic risk analysis had previously shown this sequence to be a dominant contributor to the core-melt risk for a sample plant (Sequoyah). The case i
study indicated that unavailability of the AFW system as a result of steam binding contributes significantly to the risk of core melt in PWRs. Monitoring 4
AFW to detect backleakage and to correct the situation if backleakage occurs would reduce the possibility of steam binding.
Since the AE0D study was issued, a series of events involving backflow of hot water into the AFW system occurred at McGuire 2 over a period of 7 days in August of 1984, before effective corrective action was taken.
One of these L
events involved overpressurization of the suction line and damage to instru-ments.
In November of 1984, Catawba 1 experienced in backflow of hot water l
into AFW resulting in fumes from lagging insulation and blisters of paint.
In December of 1984, the NRC's Office of Nuclear Reactor Regulation (NRR), deter-mined that steam binding of AFW was a generic issue and assigned it a r
high priority (Generic Issue 93, " Steam Binding of Auxiliary Feedwater Pumps").
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To determine the need for.short-term corrective actions, the NRC's regional F
offices conducted a survey in April and May of 1985. Of the 58 operating reactors surveyed, 39 had temperature monitoring of AFW piping at least once per shift. Of the remaining 19, 17 had normally closed gate or globe valves in the pump discharge path in addition to check valves, or some unique feature,
- r E such as complete separation of trains, that made serious safety problems unlikely..The remaining 2 licensees have subsequently decided to monitor AFW' l
pipi6g temperature.
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Although some degree of action has been taken at all units, many have not formalized these actions to detect or correct steam binding into procedures.
Without these provisions, there is little assurance that effective actions will continue in the future.
For this reason, the addressees for action are re-quested to take the following actions:
Action'for Addressees Listed in Attachment 1 t,!
1.
Develop procedures for monitoring fluid conditions within the AFW system i
on a regular basis during times when the sys+.em is required to be opera-i ble. This monitoring should ensure that fluid temperature at the AFW pump
.l discharge is maintained below saturation temperature and that-NPSH re-1, quirements are satisfied at the pump inlet. Monitoring of fluid condi-tions are recommended each shift.
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IEB 85-XX H
August 1985 Page 3 of 4 V
This item is not intended to require elaborate instrumentation. A simple means of monitoring temperature, such as touching the pipe, is a satisfac-tory approach.
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2.
Develop procedures for recognizing steam binding and for' restoring the AFW system to operable status, should steam binding occur.
3.
Procedural controls should remain in effect until some hardware fix is instituted substantially reducing the likelihood of steam binding or until -
superseded by action implemented as a result of resolution of Generic Issue 93.
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' Schedule: For operating plants, develop and implement procedures within 90 days of the date of this bulletin.
For plants under construction, develop and implement procedures within 90 days after receiving an operating license or provide an appropriate response and commitment within 1 year of the date of this bulletin, whichever comes first.
Reporting Requirements: Prepare and submit a report describing the methods F -
used to accomplish these actions.
Include the date(s) that procedures and training were implemented or scheduled to be implemented. State the frequency p~
of monitoring of the temperature.
For operating plants, submit this report
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within 120 days of the date of this bulletin.
For plants under construction.
submit the report within 120 days after receiving an operating license or within 1 year of the date of this bulletin, whichever comes first.
It is not necessary to submit the proceduras for review.
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The written report, requested above, shall be submitted to the appropriate Regional Administrator under oath or affirmation under provisions of Section m
182a, Atomic Energy Act of 1954, as amended.
In addition, the original copy of Fd the co.ver letter and a copy of the attached report should be transmitted to the t
U. S. Nuclear Regulatory Commission, Document Control Desk, Washington, DC l
20555 for reproduction and distribution.
j This request for information was approved by the Office of Management and I
Budget under blanket clearance number 3150-0011.
Comment on burden and dupli-cation should be directed to the Office of Management and Budget, Reports Management, Room 3208, New Executive Office Building, Washington, D. C. 2G503.
Although no specific request or requirement is intended, the,following informa-tion would be helpful to the NRC in evaluating the cost of this bulletin:
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1.
staff time to perform requested review and testing 2.
staff time to prepare requested documentation 1
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IEB 85-XX August 1985 Page 4 of 4
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If there are any questions regarding this matter, please contact the Regional Administrator of the appropriate NRC regional office or this office.
v James M. Taylor, Dir'ector Office of Inspection and Enforcement Technical Contacts: Mary S. Wegner, IE r
(301) 492-4511 J
C. Vernon Hodge, IE (301) 492-7275 Attachments:
1.
Addressees for Action 2.
List of Recently Issued IE Bulletins t
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IEB 85-XX August
, 1985 Page 1 of 1
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ADDRESSEES FOR ACTION:
The following PWRs having a.n OL:
BYRON 1 CRYSTAL RIVER 3 l-DAVIS-BESSE DIABLO CANYON 1 GINNA INDIAN POINT 3 KEWAUNEE
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MAINE YANKEE MILLSTONE 2 NORTH ANNA 1 I
NORTH ANNA 2 i
PALISADES POINT BEACH 1 POINT BEACH 2 I
PRAIRIE ISLAND 1 E-PRAIRIE ISLAND 2 RANCHO SECO
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SAN ONOFRE 1 ST. LUCIE 1 l
ST. LUCIE 2 SUMMER TMI 1 TROJAN r
TURKEY POINT 3 TURKEY POINT 4 sd WATERFORD 3 WOLF CREEK 1 YANKEE-ROWE r.
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