ML20058P181
| ML20058P181 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 12/14/1993 |
| From: | Murley T Office of Nuclear Reactor Regulation |
| To: | HADLEY, E.C., WE THE PEOPLE OF THE UNITED STATES (WE THE PEOPLE |
| Shared Package | |
| ML20058P174 | List: |
| References | |
| 2.206, DD-93-20, GL-92-04, GL-92-4, NUDOCS 9312230129 | |
| Download: ML20058P181 (8) | |
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DD-93 20
, UNITED STATES OF AMERICA NUCLEAR REGULATORY COMMISSION i
0FFICE OF NUCLEAR REACTOR REGULATION-.
Thomas E. Murley, Director In the Matter of )
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BOSTON EDIS0N COMPANY ) Docket-No. 50-293
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(Pilgrim Nuclear Power ) (10 CFR 2.206) ;
Station)
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DIRECTOR'S DECISION UNDER 10 CFR 2.206 l ,
INTRODUCTION On May 26, 1993, Mr. Ernest C. Hadley (Petitioner) filed a Petition in 1
accordance with 10 CFR 2.206 with the Nuclear Regulatory Commission (NRC or- I l
Commission) on behalf of We the People, Inc., of the United States. This L 'l Petition was referred to the Director, Office of Nuclear Reactor Regulation 1 (NRR), for consideration.
The Petition requested immediate action to delay the scheduled startup of the Pilgrim Nuclear Power Station (PNPS) operated by the Boston Edison Company (licensee), or, in the alternative, to order its immediate shutdown if the
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t Pilgrim Station were permitted to start up before the Petition could be acted l
L on, pursuant to 10 CFR 2.206.
The Petitioner requested that the PNPS not be permitted to operate until the licensee completes hardware modifications designed to eliminate errors in reactor water-level measurement. The Petitioner contends that the system in place at the Pilgrim facility does not adequately measure the water level of the reactor vessel and thus constitutes an unacceptable risk to the
' health and safety of the public. The Petitioner alleges that the NRC staff p$k22gg g gj 293
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informed the M blic in February 1993 that the NRC had based its' determination i that continued operation of boiling water reactors (BWRs), such as the Pilgrim I facility, did not pose a safety threat based upon generic-studies performed by r
the Boiling Water Reactor Owners Group (BWROG). These studies showed that water level errors would be measured in inches and would be self-correcting within a short period of time. The Petitioner alleges that these assurances .
were given despite the fact that on January 21, 1993, Washington Nuclear 2 ,
(WNP-2) reported a significant event in which a water level error lasted for more than I hour.
It is further alleged that this error was significantly larger than those previously observed, i Additionally, the Petitioner alleges that it requested from the NRC information used by the Pilgrim licensee to make its operability determination >
for the water-level measurement system as required by the technical- !
specifications for the Pilgrim facility. Because the NRC failed to provide this information, the Petitioner concludes that such information either does not exist or would not withstand independent scrutiny.
Finally, the Petitioner refers to a meeting of the Advisory Committee'on Reactor Safeguards (ACRS) held on May 12, 1993, which included the BWROG. It is the Petitioner's understanding that during a closed session of that meeting, the BWROG and the NRC staff confirmed that water measurement errors cou'ld be on the order of 27 feet and that neither the BWROG nor the NRC staff any longer believes the error will correct itself with the passage of time.
I have now completed my evaluation of the Petition.
For the reasons given in the discussion below, the Petitioner's request for action is denied.
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tj BACKGROUND On May 27, 1993, promptly upon receipt of the Petition, members of my staff contacted the Petitioner by telephone to inform it that the NRC staff had considered the information presented in the Petition and that it had determined not to grant the immediate relief sought. A letter to Petitioner-dated June 22, 1993, documented that decision and informed it that the NRC would take additional action with regard to the specific issues raised in the 1-l Petition within a reasonable time.
- j. DISCUSSION 1
L In August 1992, the NRC staff issued Generic Letter (GL) 92-04 requesting that licensees submit a planned schedule for long-term corrective action that may include hardware modifications, and that licensees notify the NRC of l certain short-term actions taken to address concerns about errors in level indication related to rapid depressurization. Actions addressed in'the letter included periodic. monitoring of level instrumentation leakage and implementation of procedures and operator training. Licensees were required to respond to GL 92-04 by September 27, 1992. The NRC staff agreed to extend:
the deadline for the submission of plans for long-term actions to July 1993 :d order to allow the BWROG to complete a test program which is discussed in more detail below. The Pilgrim licensee implemented the short-term actions, which were verified by an NRC inspection.
To assist in resolution of the water level issue, on August 12, 1992, the BWROG initiated a program, which included testing, to assess the potential errors in water level instrumentation that could result from rapid depressurization events. In February and March of 1993, the NRC staff visited
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t' the Electric Power Research Institute (EPRI) test facility in Charlotte, North Carolina, where the BWROG reference leg de-gas tests were conducted, to observe the reference leg de-gas tests and to discuss the technical details of the testing program with the BWROG. The NRC staff also conducted a quality assurance inspection at Continuum Dynamics Inc. (CDI), in Princeton, New Jersey, on May 4 and 5, 1993. CDI performed the testing for the BWROG at the EPRI test facility. During the inspection, the NRC staff r,ollected raw test data from the reference leg de-gas test. These raw test data are the basis of ,
the 27-foot value that was discussed at the ACRS meeting on May 12, 1993. It ;
should be noted that the magnitude of the 27-foot error is not directly applicable to the Pilgrim plant, because the magnitude of any error is plant -
specific, but the 27-foot value is demonstrative of the significant effects of ,
this phenomenon. ,
The NRC staff has considered these data relative to the actions requested in GL 92-04 and concluded that the effectiveness of the short-term actions l implemented by the Pilgrim licensee in response to GL 92-04 is not changed by I
these test results. This is because the actions of GL 92-04 were based on the assumptions that maximum theoretical calculated errors could occur and would not be self-correcting and that significant errors would not occur until t depressurization below 450 psig; the test data did not invalidate either of the'se two assumptions.
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The NRC staff also evaluated the significance of the event that occurred' at WNP-2 on January 21, 1993.' This event demonstrated that level errors can [
occur even during slow depressurization. The NRC staff' issued NRC Information ,
Notice 93-27 on April 8,1993, to alert licensees to this event.
The NRC staff also requested the BWROG to perform a generic evaluation of level indication errors during normal reactor pressure vessel depressurization. The BWROG submitted a report on May 20, 1993, discussing the effect of level errors on automatic safety system response and operator i actions during transients and accidents initiated from reduced pressure ,.
conditions of plant cooldown. This report indicated that operator actions
-l would be necessary to mitigate a drain-down event if significant errors were ,
present in multiple level instruments.
Following its review of this report, the NRC staff issued NRC Bulletin 93-03 on May 28, 1993. This bulletin requested each BWR licensee to implement short-term compensatory actions within 15 days to address concerns related to errors during slow depressurization. These actions were intended to ensure early detection of potential errors in level indication by requesting enhanced monitoring of level indication and supplemental operator training, and also to minimize evolutions that could result in draining the reactor vessel.
'The Petitioner stated that on January 21, 1993, WNP-2 reported this event. A report was received from the licensee on January 21; however, the report did not discuss the level indication errors that occurred after the reactor scram. The NRC was informed of the significant level errors that occurred February 10, 1993, after the public meeting that was held in Plymouth, Massachusetts. A written report was received on February 17, 1993.
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The staff recognizes that Pilgrim was allowed to restart on June 2, ,
1993, before implementation of these short-term compensatory actions; however, this was considered acceptable due to the time dependency of the generation of ;
non-condensible gases. During the 15 days following issuance of NRC Bulletin 93-03, when short-term actions were requested to be completed, it was not >
likely that gases would build up to a high concentration in the reference legs; therefore, it was not likely that significant errors in the level instrumentation would result. This is because gas buildup is a relatively slow process, and following a restart after a cold shutdown, as occurred at Pilgrim, the gas concentration in the reference legs is low because the1 i
reference legs have been depressurized. The NRC staff concluded that continued operation of the PNPS was acceptable, both for the short time period prior to implementation of the short-term compensatory measures, and following implementation _ of compensatory measures as requested by Bulletin 93-03 and with the actions already completed by Boston Edison in response to GL 92-04, until a permanent hardware modification was made.
With regard to the Petitioner's allegation that the NRC failed to provide information used by PNPS to make its operability determination, the licensee's operability evaluation was, however, reviewed by the Resident Inspector and that review is documented in Inspection Report 50-293/92-23, which stated, "The NRC staff also independently reviewed the bases for BECO's operability determination, and agreed with its conclusions." The report is available at the local public document room located at Plymouth Public Library,11 North Street, Plymouth, Massachusetts 02360. ,
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4 The staff has continued to monitor the licensee's actions regarding this issue. It should be noted that the Pilgrim plant was shut down in July 1993, and the licensee installed a hardware modification to their level-instrumentation before plant restart from that outage. This modification provides a continuous backfill which prevents non-condensible ' gases from building up in the reference leg. Thus, the concern that non-condensible gases will lead to level indication errors is resolved.
CONCLUSION The institution of proceedings in accordance with section 2.206, as. requested ,
by the Petitioner, is appropriate only where substantial health and safety issues have been raised. See Consolidated Edison Co. of New York (Indian
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Point Units 1, 2, and 3), CLI-75-8, 2 NRC 173, 175 (1975), and Vashington Pubife Power Supply System (WPPSS Nuclear Project No. 2), D0-84-7,19 NRC 899, 923 (1984). PNPS has completed all the action items outlined in Bulletin 93-03 and GL 92-04. Therefore, because I feel the changes already made in ,
response to Bulletin 93-03 and GL 92-04 resolve the concerns raised, I decline to take any further action with respect to the issues in this Director's Decision. Further, this Director's Decision explains why the NRC staff did not consider that-the resumed operation of PNPS prior to installation of the continuous backfill modification raised a significant risk to the public health and safety. Accordingly, insofar as the_ Petitioner has requested action pursuant to 10 CFR 2.206 beyond that which has already been taken by the licensee, the Petition is denied.
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'As provided--in 10 CFR 2.206(c), a copy of this Director's Decision will be _-
filed with the Secretary for the Commission to review. !
.i FOR THE NUCLEAR REGULATORY COMMISSION ;
deb-- I E Thomas E. Murley, Director -
Office of Nuclear Reactor Regulation -,
Dated at Rockville, Maryland, this 14thday of December 1993 .
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